How Do Rocks Provide Building Materials

Chemistry 1 Revision Booklet Unit Chemistry 1 Syllabus
At the beginning of each sub-section, activities are stated which develop candidates. skills, knowledge and understanding of how science works. Details are then given of the substantive contexts in which these skills, knowledge and understanding should be set. It is expected that, where appropriate, teachers will adopt a practical approach, enabling candidates to develop skills in addition to procedural knowledge and understanding. Note that objective test Chemistry 1a examines Section 11.1 . 11.3 and objective test Chemistry 1b examines Sections 11.4 . 11.6. 11.1 How do rocks provide building materials? The exploitation of rocks provides essential building materials. Limestone is a naturally
occurring resource that provides a starting point for the manufacture of cement, concrete and glass. Throughout Unit Chemistry 1, candidates should know that atoms are held together in molecules and lattices by chemical bonds, but no detailed knowledge of the types of chemical bonding is required. Candidates should be able to interpret chemical equations in symbol form and should be able to balance equations in terms of numbers of atoms. Candidates should use their skills, knowledge and understanding of how science works: to consider and evaluate the environmental, social and economic effects of exploiting limestone and producing building materials from it to evaluate the developments in using limestone, cement, concrete and glass as building materials, and their advantages and disadvantages over other materials. Their skills, knowledge and understanding of how science works should be set in these substantive contexts: All substances are made of atoms. A substance that is made of only one sort of atom is called an element. There are about 100 different elements. Elements are shown in the periodic table. The groups contain elements with similar properties. Atoms of each element are represented by a chemical symbol, eg O represents an atom of oxygen, Na represents an atom of sodium. Atoms have a small central nucleus around which there are electrons. When elements react, their atoms join with other atoms to form compounds. This involves giving, taking or sharing electrons and the atoms are held together by chemical bonds. (No further knowledge of ions, ionic and covalent bonding is required in this unit.) Atoms and symbols are used to represent and explain what is happening to the substances in chemical reactions. The formula of a compound shows the number and type of atoms that are joined together to make the compound.
Chemistry - General Certificate of Secondary Education, 2007/8 examination

hij No atoms are lost or made during a chemical reaction so the mass of the products equals the mass of the reactants and we can write balanced equations showing the atoms involved. Limestone, containing the compound calcium carbonate (CaCO3), is quarried and can be used as a building material.
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Calcium carbonate can be decomposed by heating (thermal decomposition) to make calcium oxide (quicklime) and carbon dioxide. Carbonates of other metals decompose on heating in a similar way. Quicklime (calcium oxide) reacts with water to produce slaked lime (calcium hydroxide). Limestone and its products have many uses, including slaked lime, mortar, cement, concrete and glass. 11.2 How do rocks provide metals and how are metals used? Metals are very useful in our everyday lives. Ores are naturally occurring rocks that provide an economic starting point for the manufacture of metals. Iron ore is used to make iron and steel. Copper can be easily extracted but copper rich ores are becoming scarce. Aluminium and titanium are useful metals but are expensive to produce. Candidates should use their skills, knowledge and understanding of how science works: to consider and evaluate the social, economic and environmental impacts of exploiting metal ores, of using metals and of recycling metals to evaluate the benefits, drawbacks and risks of using metals as structural materials and as smart materials to explain how the properties of alloys (but not smart alloys) are related to models of their structures. Their skills, knowledge and understanding of how science works should be set in these substantive contexts: Ores contain enough metal to make it economical to extract the metal and this changes over time. Unreactive metals such as gold are found in the Earth as the metal itself but most metals are found as compounds that require chemical reactions to extract the metal. Metals that are less reactive than carbon can be extracted from their oxides by reduction with carbon, for example iron oxide is reduced in the blast furnace to make iron. (Details of the blast furnace are not required.) Iron from the blast furnace contains about 96% iron. The impurities make it brittle and so it has limited uses. Removing all of the impurities would produce pure iron. Pure iron has a regular arrangement of atoms, with layers that can slide over each other, and so is soft and easily shaped, but too soft for many uses.
General Certificate of Secondary Education, 2007/8 examination - Chemistry

hij 35 Most iron is converted into steels. Steels are alloys since they are mixtures of iron with carbon and other metals. The different sized atoms added distort the layers in the structure of the pure metal, making it more difficult for them to slide over each other, and so alloys are harder. Alloys can be designed to have properties for specific uses. Low carbon steels are easily shaped, high carbon steels are hard, and stainless steels are resistant to corrosion. Many metals in everyday use are alloys. Pure copper, gold, and aluminium are too soft for many uses and so are mixed with small amounts of similar metals to make them harder for everyday use. Smart alloys can return to their original shape after being deformed. The elements in the central block of the periodic table are known as transition metals. Like other metals they are good conductors of heat and electricity and can be bent or hammered into shape.

They are useful as structural materials and for making things that must allow heat or electricity to pass through them easily. Copper has properties that make it useful for electrical wiring and plumbing. Copper can be extracted by electrolysis of solutions containing copper compounds. (No details are required of the extraction process.) The supply of copper-rich ores is limited. New ways of extracting copper from low-grade ores are being researched to limit the environmental impact of traditional mining. Low density and resistance to corrosion make aluminium and titanium useful metals. These metals cannot be extracted from their oxides by reduction with carbon. Current methods of extraction are expensive because: − there are many stages in the processes − much energy is needed. We should recycle metals because extracting them uses limited resources and is expensive in terms of energy and effects on the environment. 11.3 How do we get fuels from crude oil? Crude oil is an ancient biomass found in rocks from which many useful materials can be produced. Crude oil can be fractionally distilled. Some of the fractions can be used as fuels. Candidates should use their skills, knowledge and understanding of how science works: to evaluate the impact on the environment of burning hydrocarbon fuels to consider and evaluate the social, economic and environmental impacts of the uses of fuels to evaluate developments in the production and uses of better fuels, for example ethanol and hydrogen.
Chemistry - General Certificate of Secondary Education, 2007/8 examination

hij Their skills, knowledge and understanding of how science works should be set in these substantive contexts: Crude oil is a mixture of a very large number of compounds. A mixture consists of two or more elements or compounds not chemically combined together. The chemical properties of each substance in the mixture are unchanged. It is possible to separate the substances in a mixture by physical methods including distillation. Most of the compounds in crude oil consist of molecules made up of hydrogen and carbon atoms only (hydrocarbons). Most of these are saturated hydrocarbons called alkanes, which have the general formula CnH2n+2 Alkane molecules can be represented in the following forms: − C2H6 − HH
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H

C

C

H

HH The many hydrocarbons in crude oil may be separated into fractions, each of which contains molecules with a similar number of carbon atoms, by evaporating the oil and allowing it to condense at a number of different temperatures. This process is fractional distillation. Some properties of hydrocarbons depend on the size of their molecules. These properties influence how hydrocarbons are used as fuels.

Most fuels contain carbon and/or hydrogen and may also contain some sulfur. The gases released into the atmosphere when a fuel burns may include carbon dioxide, water (vapour), carbon monoxide and sulfur dioxide. Particles may also be released. Sulfur dioxide causes acid rain, carbon dioxide causes global warming, and particles cause global dimming. Sulfur can be removed from fuels before they are burned, for example in vehicles. Sulfur dioxide can be removed from the waste gases after combustion, for example in power stations. 11.4 How are polymers and ethanol made from oil? Fractions from the distillation of crude oil can be cracked to make smaller molecules including unsaturated hydrocarbons such as ethane. Unsaturated hydrocarbons can be used to make polymers and ethene can be used to make ethanol. Candidates should use their skills, knowledge and understanding of how science works: to evaluate the social and economic advantages and disadvantages of using products from crude oil as fuels or as raw materials for plastic and other chemicals to evaluate the social, economic and environmental impacts of the uses, disposal and recycling of polymers
General Certificate of Secondary Education, 2007/8 examination - Chemistry

hij 37 to evaluate the advantages and disadvantages of making ethanol from renewable and nonrenewable sources. Their skills, knowledge and understanding of how science works should be set in these substantive contexts: Hydrocarbons can be broken down (cracked) to produce smaller, more useful molecules. This process involves heating the hydrocarbons to vaporise them and passing the vapours over a hot catalyst. A thermal decomposition reaction then occurs. The products of cracking include alkanes and unsaturated hydrocarbons called alkenes. Alkenes have the general formula CnH2n Unsaturated hydrocarbon molecules can be represented in the following forms: − C2H4 − Some of the products of cracking are useful as fuels. Ethene can be reacted with steam in the presence of a catalyst to produce ethanol. Alkenes can be used to make polymers such as poly(ethene) and poly(propene). In these reactions, many small molecules (monomers) join together to form very large molecules (polymers). Polymers have properties that depend on what they are made from and the conditions under which they are made. For example, slime with different viscosities can be made from poly(ethenol). Polymers have many useful applications and new uses are being developed, for example: new packaging materials, waterproof coatings for fabrics, dental polymers, wound dressings, hydrogels, smart materials, including shape memory polymers. Many polymers are not biodegradable, so they are not broken down by microorganisms and this can lead to problems with waste disposal. 11.5 How can plant oils be used? Many plants produce useful oils which can be converted into consumer products including processed foods. Vegetable oils can be hardened to make margarine. Biodiesel fuel can be produced from vegetable oils.

Candidates should use their skills, knowledge and understanding of how science works: to evaluate the effects of using vegetable oils in foods and the impacts on diet and health to evaluate the benefits, drawbacks and risks of using vegetable oils to produce fuels to evaluate the use, benefits, drawbacks and risks of ingredients and additives in foods.
Chemistry - General Certificate of Secondary Education, 2007/8 examination

hij Their skills, knowledge and understanding of how science works should be set in these substantive contexts: Some fruits, seeds and nuts are rich in oils that can be extracted.
The plant material is crushed and the oil removed by pressing or in some cases by distillation. Water and other impurities are removed. Vegetable oils are important foods and fuels as they provide a lot of energy. They also provide us with nutrients. Oils do not dissolve in water. They can be used to produce emulsions. Emulsions are thicker than oil or water and have many uses that depend on their special properties. They provide better texture, coating ability and appearance, for example in salad dressings and ice creams. Vegetable oils that are unsaturated contain double carbon carbon bonds. These can be detected by reacting with bromine or iodine. Vegetable oils that are unsaturated can be hardened by reacting them with hydrogen in the presence of a nickel catalyst at about 60 °C. The hydrogenated oils have higher melting points so they are solids at room temperature, making them useful as spreads and in cakes and pastries. Processed foods may contain additives to improve appearance, taste and shelf-life. These additives must be listed in the ingredients and some permitted additives were given E-numbers. Chemical analysis can be used to identify additives in foods. Artificial colours can be detected and identified by chromatography. 11.6 What are the changes in the Earth and its atmosphere? The Earth and its atmosphere provide everything we need. The Earth has a layered structure. Large-scale movements of the Earth.s crust can cause changes in the rocks. The Earth.s atmosphere was originally very different from what it is today. It has been much the same for the last 200 million years and provides the conditions needed for life on Earth. Recently human activities have produced further changes. Candidates should use their skills, knowledge and understanding of how science works: to
explain why the theory of crustal movement (continental drift) was not generally accepted for many years after it was proposed to explain why scientists cannot accurately predict when earthquakes and volcanic eruptions will occur to explain and evaluate theories of the changes that have occurred and are occurring in the Earth.s atmosphere to explain and evaluate the effects of human activities on the atmosphere. Their skills, knowledge and understanding of how science works should be set in these
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substantive contexts: The Earth consists of a core, mantle and crust. Scientists once thought that the features of the Earth.s surface were the result of the shrinking of the crust as the Earth cooled down following its formation.
General Certificate of Secondary Education, 2007/8 examination - Chemistry

hij

Summary questions rocks and building
This sheet is a summary of the work done in this chapter. Answer all the questions in the spaces provided. 1 Particles and chemicals. Eliminate the wrong option in the following true/false questions. a) An element contains only one type of atom. b) Silver oxide is an element. c) Calcium carbonate CaCO3 contains three elements. d) The formula of calcium carbonate contains six atoms. e) Sand and water is a mixture. f) Sand and water are hard to separate. g) Decomposition means the same as synthesis. h) CO2 contains two elements and three atoms. 2 The decomposition of metal carbonates. a) The two elements present in all carbonates are _______________ and _______________. b) Magnesium carbonate has the formula, ____________. It is a compound because it contains more than one type of _______________ bonded _______________. When it is heated, it _____________ to give magnesium ______________ and carbon _____________________ gas. This type of reaction is called _____________________ decomposition. The gas can be tested for using _________________________ which goes ______________ if the gas is present. This question is about limestone. For each alternative, cross out the wrong answer. Limestone is calcium carbonate/calcium sulfate and has the chemical formula CaCO3/CaSO4. It is a very rare/abundant chemical and has many uses. When it is heated in a limekiln/blast furnace it decomposes to give solid calcium sulfide/calcium oxide and the gas carbon dioxide. This reaction is an example of catalytic/thermal decomposition. One of the uses of limestone is as a building material. Also, when it is heated with sand/clay it gives cement and when it is heated with a mixture of sand/cement and sodium carbonate/sodium acetate it gives glass. true/false true/false true/false true/false true/false true/false true/false true/false

3

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Quicklime and slaked lime. Complete the following paragraph by filling in the gaps. Quicklime has the chemical name calcium ______________ and is formed when limestone (chemical name ____________ __________) is heated strongly. When water is added to quicklime, an ________________ reaction occurs which gives out a lot of heat energy. This reaction can be used in kits to ____________ up food or as a hand warmer. The substance formed in the reaction between quicklime and water is called ___________ ____________ and has the chemical name ___________ ______________ (chemical formula = Ca(OH)2). This chemical is used in the __________ trade where it is mixed with sand and water to form ___________ mortar. When a lot of water is added to _______________ _________________, lime water is formed and this reacts with carbon ___________ gas to give calcium _____________ and water. The calcium ____________ is a solid and turns the lime water ________, because we get back to calcium ______________ which is what we started off with. This series of reactions is called the ____________ cycle. Balancing equations. Complete the following equations by either putting in the missing numbers or the formulae for the missing substances. Remember if the number before the formula is 1 (one) then we just leave it. a) H2 (g) + Cl2 (g) → __HCl (g) b) 2Mg (s) + O2 (g) → __MgO (s) c) __H2 (g) + O2 → __H2O (l) d) CaCO3 (s) → CaO (s) + _____ (g) e) __HCl (aq) + CaCO3 (s) → CaCl2 (aq) + CO2 (g) + H2O (l) f) Fe (s) + S (s) → _____ (s)

5

Rocks and building
1 The diagram shows a molecule of ammonia, NH3. H—N—H | H Match the words A, B, C and D with spaces 1 to 4 in the sentences. A bonds .................... B C D electrons .................... elements .................... symbols ....................

Ammonia is a compound made from two .........1......... . The atoms in the molecule are represented by .........2......... . The atoms in ammonia are held together by chemical .........3.......... . Each atom has a nucleus surrounded by .........4.......... . 2 The diagram shows stages in making cement and concrete. (4)

Match statements A, B, C and D with the numbers 1 to 4 to describe what happens in this process. A B C D 3 cement mixed with sand and crushed rock ………. concrete produced ………. limestone heated in a kiln with clay ………. water added to mixture ………. (4)

(a) Slaked lime is made by reacting quicklime with: A B C D carbon dioxide oxygen sulfuric acid water (1)

(b) The chemical name for slaked lime is: A B C D calcium chloride calcium hydroxide calcium oxide calcium sulfate (1)

(c) Slaked lime can be used to make: A B C D bricks clay mortar quicklime (1)

(d) Lime water goes cloudy when reacted with carbon dioxide. Which substance is produced? A B C D 4 calcium carbonate calcium chloride calcium oxide calcium sulphate (1)

Glass is used in almost all buildings. (a) Suggest two properties of glass that make it useful in buildings. .......................................................................................................................... .......................................................................................................................... (2)

(b) Suggest and explain one disadvantage of using glass in buildings. .......................................................................................................................... .......................................................................................................................... (2) 5 One of the largest limestone quarries in the United Kingdom is near the town of Buxton. It is in the Peak District National Park, an area popular with tourists.

Suggest three social or environmental issues involved in quarrying limestone in the Peak District. ................................................................................................................................. ................................................................................................................................. ................................................................................................................................. (3) 6 Mortars used in most modern buildings are made using cement. A student tested the strength of a ready-mixed mortar. He did this by dropping a mass onto a small mortar beam from increasing heights until the beam broke in half. He tested 4 beams made from the mortar. His results were 20 cm, 50 cm, 65 cm and 15 cm. (a) What was the range of the student’s results? .......................................................................................................................... .......................................................................................................................... (2) (b) Work out the mean of his results. .......................................................................................................................... (1) (c) Comment on the precision of his results. .......................................................................................................................... (1)

(d) (i) Besides cement, what was the other solid in the ready-mixed mortar? .................................................................................................................... (1) (ii) What other solid is needed to make concrete instead of mortar? .................................................................................................................... (1)

Rocks and Building past paper questions
1. Magnesium chloride is a useful salt. The flow diagram shows how it can be made. limestone calcium hydroxide seawater

magnesium hydroxide

acid

magnesium chloride

(i)

Describe how calcium hydroxide can be made from limestone. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................
(2)

(ii)

Write a word equation for the neutralisation of magnesium hydroxide with a suitable acid to form magnesium chloride. .....................................................................................................................................
(2) (Total 4 marks)

2.

(a)

A student did some experiments to study limestone. In one experiment, a piece of limestone was heated very strongly as shown in the diagram.

Piece of limestone

Tin lid

The limestone was converted into quicklime and carbon dioxide. heat Limestone (i) quicklime + carbon dioxide

Complete the symbol equation for this reaction. heat CaCO3 ................... + CO2
(1)

(ii)

Give the chemical name for quicklime. ...........................................................................................................................
(1)

(b)

A student did another experiment to measure the mass of quicklime formed when 2 grams of limestone was strongly heated. The limestone was weighed before and after being heated, using a balance reading to the nearest gram. The results are shown in the table. Mass of limestone before heating in grams Mass of quicklime formed in grams (i) (ii) 2 1

What mass of carbon dioxide was produced? ............................................... g
(1)

Suggest ways in which the student could improve the accuracy and reliability of the measurements. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................

...........................................................................................................................
(3) (Total 6 marks)

3.

Limestone is a useful rock. (a) Limestone can be used to make several useful products. Draw rings around two useful products made from limestone. cement (b) diesel glass petrol plastic
(2)

A student did some experiments to study limestone. In one experiment, a piece of limestone was heated very strongly as shown in the diagram.

Piece of limestone

Tin lid

(i)

Suggest one safety precaution that the student should take when doing this experiment. ........................................................................................................................... ...........................................................................................................................
(1)

(ii)

When limestone is heated it forms two products; a white powder and a gas. Complete the word equation by choosing the correct product from the list. calcium carbide oxide calcium hydroxide calcium nitride calcium

calcium carbonate  heat → …………………………………..…… + carbon  dioxide (limestone)
(1)

(c)

The student did another experiment using 2.00 grams of limestone. The limestone was weighed before and after being heated. The student then repeated this experiment. A new sample of 2.00 grams of limestone was used.

The results are shown in the table. Experiment 1 Mass of limestone before heating in grams (g) Mass of limestone after heating in grams (g) Mass lost in grams (g) (i) 2.00 1.12 0.88 Experiment 2 2.00 1.10 0.90

Calculate the average mass lost for the two experiments. ................................................................................................................. .......... Average mass lost = .............................................. g
(1)

(ii)

Explain why it was important for the student to repeat this experiment. ........................................................................................................................... ...........................................................................................................................
(1)

(iii)

Suggest why the mass lost was not the same for the two experiments. ........................................................................................................................... ...........................................................................................................................
(1)

(iv)

Explain why a balance which measures to the nearest 0.1 g would not be suitable for this experiment. ........................................................................................................................... ...........................................................................................................................
(1)

(v)

Suggest what mass of carbon dioxide would be produced when 2.00 g of limestone is heated. Mass of carbon dioxide produced = ........................g
(1)

(d)

The drawing shows a limestone quarry.

(i)

Suggest two ways in which the limestone quarry may harm the environment. 1 ........................................................................................................................ ........................................................................................................................... ........................................................................................................................... 2 ........................................................................................................................ ...........................................................................................................................
(2)

(ii)

Suggest two ways in which the limestone quarry is of benefit to people. 1 ........................................................................................................................ ........................................................................................................................... 2 ........................................................................................................................ ...........................................................................................................................
(2) (Total 13 marks)

4.

Limestone is an important raw material. (a) Limestone has many uses. Choose from the list two important materials made from limestone. cement poly(ethene) diesel oil sodium hydroxide glass sulphuric acid

1. ................................................................................................................................ 2. ................................................................................................................................
(2)

(b)

The diagram shows a lime kiln. The limestone is heated by the burning coal.

Limestone and coal

Waste gases

Stream of air

Quicklime

(i)

Suggest why hot air is blown into the lime kiln. .......................................................................................................................... ..........................................................................................................................
(1)

(ii)

Give two reactions which produce carbon dioxide in the lime kiln. Reaction 1 ........................................................................................................ .......................................................................................................................... Reaction 2 ........................................................................................................ ..........................................................................................................................
(2)

(c)

(i)

Quicklime (calcium oxide) can be converted to slaked lime (calcium hydroxide) by adding water. Write a word equation to represent this reaction. ..................................... + ...................................... → ....................................
(1)

(ii)

Why do farmers sometimes add slaked lime to acidic soil? .......................................................................................................................... ..........................................................................................................................
(1) (Total 7 marks)

.

An old lime kiln made in the ground is shown.

Stones

Coal Calcium carbonate

Soil Soil

Fire

(a)

The thermal decomposition of calcium carbonate makes a white solid and carbon dioxide. (i) Name a naturally occurring form of calcium carbonate. ........................................................................................................................... ...........................................................................................................................
(1)

(ii)

What does thermal decomposition mean? ........................................................................................................................... ...........................................................................................................................
(2)

(iii)

Suggest and explain the purpose of the coal. ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................
(2)

(iv)

Write a word equation for the thermal decomposition of calcium carbonate. ................................... → ................................... + ....................................
(2)

(b)

The diagrams show what happens when drops of cold water are added to the white solid formed by heating calcium carbonate.

Water White solid
(ii) What type of chemical reaction takes place?

Cracks appear

...........................................................................................................................
(1)

(ii)

Give the chemical name of the solid formed. Give a use of this solid. Name ................................................................................................................ Use ...................................................................................................................
(2) (Total 10 marks)

Summary questions metals
Complete questions 1–5, and then do the ‘traffic lights’ self-assessment at the end. 6 Mark the following statements about crude oil and its fractions as true or false. i) j) l) Metals are found in rocks called ores. Reactive metals are often found in their native state. Carbon is often used to reduce metal oxides to the metal. true/false true/false true/false true/false true/false true/false true/false true/false true/false

k) Reduction is the gain of oxygen by a metal. m) Copper can be obtained from its ores by smelting. n) Iron is produced in a blast furnace. o) In a blast furnace, limestone is added to reduce iron oxide. p) In a blast furnace, the iron oxide is reduced by carbon. q) The commonest ore of iron is called galena. 7 Fill in the gaps in the following paragraphs.

Alloys are _____________ of metals. Steel is an alloy of _________. It is made up of this metal plus a small amount of _____________. Other _____________ can be added to steel to give it different ______________. For example chromium can be added to make ________________ steel. This type of steel is important because it does not _________. Brass is an alloy of _____________ and zinc. The ______________ is made harder by the addition of the zinc. In brass the _______________ copper atoms cannot slide across each other so easily because the larger _______ atoms get in the way. The properties of alloys and steels determine their uses. For example, ________________ steel is used for cutlery. Brass is used for ___________ instruments because it looks good and does not corrode. 8 Cross out the wrong alternatives in the following paragraph. Aluminium is a shiny grey/orange metal. It is heavy/light and a bad/good electrical conductor. Therefore it is used for underground/overhead electrical cables. Other metals can be added to aluminium to make aluminium ores/alloys. Even though aluminium is quite reactive/unreactive it does not corrode and this decreases/increases its usefulness. Aluminium should be recycled because it needs lots of electrical/kinetic energy to extract it. Also, aluminium ore or bauxite/haematite is running out. Titanium is a useful metal because it has a high conductivity/strength to weight/volume ratio. This means it is very strong and light/heavy and therefore, like aluminium, it can

be used in the fishing/aerospace industry. It also does not corrode and is used medically to make replacement hips/eyes for people. 9 Cross out the wrong alternatives in the following paragraph. There are several different ways of extracting metals. In ancient times the most reactive/unreactive metals like copper were extracted first. The method used here was either smelting/melting or oxidation/reduction. Reduction is the addition/removal of oxygen from the metal oxide. When we discovered electricity the more reactive/unreactive metals were then extracted using electrolysis/smelting. Another method that can be used is displacement of a less reactive metal by a more/less reactive one. For example, magnesium will displace copper from magnesium/copper sulfate. Phytomining is a very recent method of extraction. This involves the selective uptake/emission of a metal by plants/animals. The plant/animal is then harvested along with the metal. 10 Fill in the gaps in the following paragraph. The transition metals are found in the ____________ of the periodic table. They form _______________ compounds. Their properties are typical of metals but they are often ____________ than non-transition metals. For example, iron can be used for __________ covers because it is heavy and will stay in place. They are d____________ and therefore easy to draw into wires and m_____________ so they can be shaped easily.

Traffic light self-assessment
For each of the following topics, assess whether you: Red = Do not understand. Amber = Are not sure. Green = Understand. 1 Know the names of some metals found native and some found in metal ores. Red/amber/green 2 3 4 5 6 7 8 9 Know how to extract metals by smelting and reduction of their oxides. Red/amber/green Explain and understand the uses of steels. Explain that alloys are more useful than pure metals. Know about smart alloys and their uses. Know the properties of transition metals. Know the methods for extracting copper. copper. Red/amber/green Red/amber/green Red/amber/green Red/amber/green Red/amber/green Red/amber/green Red/amber/green

Compare the environmental impacts of the different methods of extracting Understand the uses and properties of aluminium and titanium.

Rocks and metals
1 This question is about the uses of these metals: A C aluminium gold B D copper iron

Which of these metals is used: (a) as the main metal in alloys to build aircraft? .................... (b) in alloys to make jewellery? .................... (c) to make all steels? .................... (d) to make water pipes and electrical wiring? .................... 2 Choose a metal from the list A to D to match each description. A C aluminium gold B D chromium titanium (4)

(a) A metal that is strong at high temperatures and resists corrosion. .......................................................................................................................... (b) An unreactive metal found native in the Earth. ..........................................................................................................................

(c) This metal has a low density and is extracted by electrolysis. .......................................................................................................................... (d) This metal is mixed with iron to make high alloy steels. .......................................................................................................................... (4) 3 Use words from the list A to D to complete the word equations. A C copper sodium B D iron water

(a) copper oxide + sulfuric acid → copper sulfate + ……………….. (b) copper sulfate + iron → ……………….. + iron sulfate (c) iron oxide + carbon → ……………….. + carbon dioxide (d) titanium chloride + ……………….. → titanium + sodium chloride 4 (4)

A student tested the flexibility of four different alloy rods. She suspended a mass from the end of the rods which were fixed at the other end to the edge of a bench. She measured how far each rod bent. Which words describe the ‘distance the rod bent’? A B C D a categoric, independent variable. a continuous, independent variable. a categoric, dependent variable. a continuous, dependent variable. (1)

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Name the types of substance described in each part of this question. (a) These elements are hard, tough and strong, conduct heat and electricity well and are found in the middle of the periodic table. .......................................................................................................................... (b) These rocks contain enough metal to make it worth extracting. .......................................................................................................................... (c) This is a metal that contains other elements to give it specific properties. .......................................................................................................................... (d) These materials are smart because they can return to their original shape when heated and are used by surgeons to hold broken bones while healing. .......................................................................................................................... (4)

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Iron is extracted from iron oxide by removing oxygen. (a) What name is given to a reaction in which oxygen is removed from a compound? .......................................................................................................................... (1) (b) Name an element that could be used to remove oxygen from iron oxide. .......................................................................................................................... (1) (c) Write a word equation for the reaction that would take place in (b). .......................................................................................................................... .......................................................................................................................... (2)

7

Titanium is used to make replacement hip joints. One reason why titanium can be used in this way is that it resists corrosion. (a) How is titanium protected from corrosion? .......................................................................................................................... (1) (b) Suggest two other properties of titanium that make it suitable for this use. .......................................................................................................................... .......................................................................................................................... (2)

8

Most of the world’s steel is now made in Asia.

Suggest two reasons why it costs less to make steel in Asia than in Europe. ..........................................................................................................................

.......................................................................................................................... (2) 9 New methods using bacteria, fungi and plants are being developed to extract copper. Suggest three reasons why these new methods have been developed. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... (3)

Metals past paper questions
1. A student was trying to extract the metals from lead oxide and aluminium oxide. She heated each oxide with carbon in a fume cupboard as shown below.

lumps of charcoal (carbon) mixture of powdered carbon and the metal oxide very strong heat
She was able to extract lead from lead oxide but not aluminium from aluminium oxide. (i) Explain the results of these experiments. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (ii) Complete this word equation for the reaction between lead oxide and carbon. lead oxide + carbon → .................................... + ....................................... 2. Cassiterite is an ore of the metal tin. (a) What is an ore? .................................................................................................................................... ....................................................................................................................................
(2) (Total 5 marks)

(b)

Some metals are obtained by removing oxygen from the metal oxide. What name do we give to this chemical reaction? ....................................................................................................................................
(1)

(c)

Name one metal which must be extracted from its melted ore by electrolysis rather than by using carbon. ....................................................................................................................................
(1) (Total 4 marks)

3.

The word box contains the names of some metals. aluminium (i) copper iron manganese zinc

The drawing shows the view from a window. Choose from the names of metals in the box to complete the three spaces.

(3)

(ii)

What is the name of the metal in the word box which has the chemical symbol Fe? .....................................................................................................................................
(1)

(iii)

What is the name of one metal in the word box which often has coloured

compounds? .....................................................................................................................................
(1) (Total 5 marks)

4.

One step in the manufacture of lead is the reduction of lead oxide with carbon. Lead and carbon dioxide are the products of this reaction. (a) Write a word equation for this reaction. .....................................................................................................................................
(1)

(b)

What is meant by “reduction”? .....................................................................................................................................
(1) (Total 2 marks)

5.

Alloys have many important uses. (a) State the meaning of the term alloy. ..................................................................................................................................... .....................................................................................................................................
(1)

(b)

This wedding ring is made from 18 carat gold. This is an alloy made from gold and silver.

The wedding ring has to last many years when worn every day. Suggest and explain why the ring is made from an alloy rather than pure gold. ..................................................................................................................................... .....................................................................................................................................
(2)

(c)

The metal frame of these glasses is made from a smart alloy. This alloy is made from titanium and nickel.

Give one advantage of making the frame from a smart alloy, instead of an ordinary metal. ..................................................................................................................................... .....................................................................................................................................
(1) (Total 4 marks)

6.

The table gives information about some metals. Name of the metal Aluminium Platinum Iron Gold (a) Cost of one tonne of the metal in December 2003 (£) 883 16720000 216 8236800 Percentage of the metal in the crust of the earth (%) 8.2 0.0000001 4.1 0.0000001

Use information in the table to suggest why gold and platinum are very expensive metals. ..................................................................................................................................... .....................................................................................................................................
(1)

(b)

Aluminium and iron are made by reduction of their ores. (i) Name the element that is removed from the ores when they are reduced. ...........................................................................................................................
(1)

(ii)

Use the reactivity series on the Data Sheet to suggest a metal that would reduce aluminium ore.

...........................................................................................................................
(1)

(c)

Aluminium is made by the reduction of molten aluminium ore, using a very large amount of electricity. (i) How is iron ore reduced in a blast furnace to make iron? ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................
(2)

(ii)

Suggest why aluminium is more expensive than iron. ........................................................................................................................... ...........................................................................................................................
(1) (Total 6 marks)

Summary questions Crude Oil
Complete questions 1–4 and then do the ‘traffic lights’ self-assessment at the end. 10 Mark the following statements about crude oil and its fractions as true or false. r) t) Crude oil is a mixture of different compounds. Crude oil can be split up into fractions using filtration. boiling points. v) The fractions contain hydrocarbons called alkanes. x) The general formula of the alkanes is CnH2n+2. y) The fuels from crude oil are non-renewable. z) The alkane with ten carbons has the formula C10H24. aa) The process used to separate the fractions is called fractional distillation. with the place where they leave the column. true/false 11 Given below is a simple diagram of a fractionating column. Match the fractions true/false true/false true/false true/false true/false true/false true/false true/false s) Crude oil is a pure substance. u) The fractions are easily separated because they have different

w) Hydrocarbons contain the elements hydrogen, carbon and oxygen. true/false

12 Fill in the gaps in the following paragraphs. When hydrocarbon fuels burn in air they react with ______________ gas. If there is sufficient air present then ________________ combustion takes place. __________ is formed along with carbon dioxide gas. If there is not enough air for ______________ combustion then incomplete combustion takes place. If this happens then the poisonous gas, _________________ __________________ is formed. This gas stops _____________ getting to the brain and the person can become asphyxiated. If there is very little air present then solid ______________ can form and this forms as a ____________ solid deposit. If the hydrocarbon fuel contains sulfur then the gas ________________ dioxide can form. This dissolves in water in rain clouds to form _________ rain. This can cause damage to ___________________, harm trees and affect the health of _______________. 13 Cross out the wrong alternatives in the gaps in the following paragraphs. Fossil fuels contain hydrocarbons/carbohydrates and when these burn pollutants are produced. Carbon dioxide is a greenhouse/white house gas and reduces the amount of heat/sound energy lost by radiation. This causes global cooling/warming. This could have several consequences, some of which might be harmful. For example, the ice-caps might freeze/melt and this could raise/lower water levels in the oceans and cause flooding. When diesel fuels burn they give off particulates/participles and these are tiny gas/solid particles thought to cut down light from the Moon/Sun. This in turn causes global illumination/dimming. Other pollutants formed by the burning of fossil fuels are sulfur dioxide/trioxide and oxides of nitrogen/argon. These are thought to cause asthma/blindness in humans.

Traffic light self-assessment
For each of the following topics assess whether you:

Red = Do not understand Amber = Are not sure Green = Understand 14 Crude oil is a fossil fuel. 15 Crude oil is a non-renewable source of fuel. 16 Crude oil is a mixture of hydrocarbons. 17 Crude oil is separated using fractional distillation. fractionating column. 20 Alkanes have the general formula, CnH2n+2.

Red/amber/green Red/amber/green Red/amber/green Red/amber/green Red/amber/green Red/amber/green Red/amber/green

18 The fractions with low boiling points come off near the top of the 19 Hydrocarbons are compounds of hydrogen and carbon only. Red/amber/green 21 Crude oil from different areas of the world have different thicknesses. 22 Hydrocarbons burn in air to form carbon dioxide and water. particulates which are both poisonous. nitrogen which both form acid rain. Red/amber/green Red/amber/green Red/amber/green Red/amber/green 26 Particulates are thought to cause global dimming. 27 Gasohol and biodiesel are cleaner renewable fuels. Red/amber/green Red/amber/green

23 Incomplete combustion of hydrocarbons gives carbon monoxide and 24 When fossil fuels are burned in air they give off sulfur dioxide and oxides of 25 Carbon dioxide is a greenhouse gas and is a cause of global warming.

Crude oil
1 The following compounds are found in crude oil: A B C D C3H8 C8H18 C12H26 C16H34

Which of these compounds: (a) has the highest boiling point? .................... (b) catches fire most easily? .................... (c) is collected at the top of the fractionating column when crude oil is distilled? .................... (d) is the thickest liquid? .................... 2 Crude oil is a mixture of many different hydrocarbons. (4)

Match the words A, B, C and D with spaces 1 to 4 in the sentences. A B C D alkanes .................... compounds .................... fractions .................... molecules ....................

(a) Crude oil is separated by distillation into .........1......... containing hydrocarbons with similar boiling points. (b) Hydrocarbons with the smallest .........2......... have the lowest boiling points. (c) Hydrocarbons are .........3......... of hydrogen and carbon only. (d) Crude oil contains mostly saturated hydrocarbons called .........4......... . 3 The table shows the number of carbon atoms in the molecules of four fuels obtained from crude oil. Fuel petroleum gases petrol kerosene diesel oil Number of carbon atoms in molecules 2–4 4–10 10–15 14–19 (4)

(a) The fuel with the highest boiling point is … A B C D petroleum gases petrol kerosene diesel oil (1)

(b) Petrol … A B C D has a higher boiling point than diesel oil. is a thinner liquid than diesel oil. ignites less easily than kerosene. has larger molecules than kerosene. (1)

(c) The molecule C4H10 could be in … A B C D petrol only. petrol and kerosene. petrol and petroleum gases. petroleum gases only. (1)

(d) Which one of the following is a saturated hydrocarbon that could be in diesel oil? A B C D 4 C12H26 C16H32 C17H36 C18H38O (1)

Pentane, C5H12, is a hydrocarbon fuel. It burns completely in plenty of air. (a) Name the gas in the air that pentane reacts with when it burns. .......................................................................................................................... (1) (b) Write a word equation for the combustion of pentane in plenty of air. .......................................................................................................................... .......................................................................................................................... (2) (c) Write a balanced symbol equation for this reaction. .......................................................................................................................... .......................................................................................................................... (2) (d) When the air supply is limited a poisonous gas is produced. Name this gas. .......................................................................................................................... (1) (e) Write a balanced symbol equation for the combustion of pentane in a limited supply of air. .......................................................................................................................... .......................................................................................................................... (2)

5

(a) Suggest two fuels that could be used in place of fossil fuels. Give one advantage and one disadvantage for each of the fuels you have named. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................

.......................................................................................................................... (6) 6 Oil companies promote the use of low sulfur fuels. (a) Explain why it is better to use low sulfur fuels. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... (3) (b) Suggest one other reason why oil companies advertise that their fuels are low in sulfur. .......................................................................................................................... (1) 7 Crude oil is separated by fractional distillation. In oil refineries this is done in tall towers called fractionating columns.

Give the main steps in this process and explain how the different fractions are separated in a fractionating column. ................................................................................................................................. ................................................................................................................................. ................................................................................................................................. ................................................................................................................................. (4)

Crude oil past paper questions
1. Methane CH4 contains the elements carbon and hydrogen only. A student wanted to find out which new substances are produced when methane is burned. The student set up the apparatus shown below.

suction pump

methane gas

ice + water liquid collects here

limewater turns milky

(a)

Which gas in the air reacts with methane when it burns? .....................................................................................................................................
(1)

(b)

Name the liquid collected. .....................................................................................................................................
(1)

(c)

Name the gas which turns limewater milky. .....................................................................................................................................
(1)

(d)

When methane burns an exothermic reaction takes place. What is meant by an exothermic reaction? ..................................................................................................................................... .....................................................................................................................................
(2) (Total 5 marks)

2.

The equation below shows the cracking of a hydrocarbon compound into two different compounds, A and B.
H H C H H C H H C H H C H H C H H C H H H C H H C + H H H C H H C H H C H H C H H

Compound A

Compound B

(a)

State two differences between the structures of compounds A and B. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................
(2)

(b)

Why is compound A useful in industry? ..................................................................................................................................... .....................................................................................................................................
(1) (Total 3 marks)

3.

Crude oil is a mixture of long-chain hydrocarbons. It is cracked to produce a mixture of smaller alkanes and alkenes. Among the gases formed are ethane and ethene. (a) Write the structural formula for: (i) ethane

(1)

(ii)

ethene

(1)

(iii)

Give an example of one chemical reaction which both ethane and ethene undergo. ...........................................................................................................................
(1)

(iv)

Describe how to distinguish between ethane and ethene. Include a description of the practical method you would use and what you would expect to observe. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................
(3)

(b)

Ethene may be polymerised to form a polymer. Give the name of the polymer and a use for it. Name ............................................... Use ...........................................................
(1) (Total 7 marks)

4.

Crude oil and natural gas are mixtures of hydrocarbons. They are obtained from wells drilled into rocks where they are trapped. (a) (i) What is the name of the process used to separate the different hydrocarbons in crude oil? ...........................................................................................................................
(1)

(ii)

Methane is one of the gases obtained when crude oil is separated. Give the name of another hydrocarbon gas obtained from this process. ...........................................................................................................................
(1)

(b)

A fuel used in gas cookers is natural gas. It is mainly methane, CH4. (i) Complete the word equation for the complete combustion of methane. methane + oxygen → .................................... + .............................................. (ii) What different gas is produced by the incomplete combustion of methane? .........................................................................................................................
(1) (Total 5 marks) (2)

5.

Alkanes and alkenes are obtained from crude oil. (a) (i) What method is used to separate crude oil into its components? ..........................................................................................................................
(1)

(ii)

The box contains the names of five components that can be separated from crude oil diesel fuel oil paraffin petrol propane gas

Write the list in order of increasing boiling point, starting with the lowest boiling point. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................
(1)

(b)

Draw the displayed structural formulae for propane and ethene. propane ethene

(4) (Total 6 marks)

6.

The diagram shows a reaction which takes place in an oil refinery.
H H C H H C H H C H H C H H C H H H C H H C + H H H C H H C H H C H H C H H

H

C H

Compound X

Compound Y

Compound Z

(a)

X, Y and Z are all examples of which type of compound? .....................................................................................................................................
(1)

(b)

What type of chemical reaction takes place when compound X is converted into compounds Y and Z? .....................................................................................................................................
(1)

(c)

Compounds Y and Z are both useful substances. Compound Y is unsaturated. Compound Z is saturated. (i) Suggest one use for compound Y. ...........................................................................................................................
(1)

(ii)

Suggest one use for compound Z. ...........................................................................................................................
(1) (Total 4 marks)

7.

Fractional distillation is used to separate fractions in the crude oil mixture. (a) Draw a line to join each fraction to its use as a fuel. One line has been drawn for you.

Fraction

Use as a fuel

40°C

Petrol

Buses and lorries

180°C

Paraffin

Cars

260°C Crude oil 350°C

Diesel oil Fuel oil

Heating systems Jet aircraft

Heat
(2)

(b)

(i)

Why does petrol separate from the other fractions in the crude oil mixture? .......................................................................................................................... ..........................................................................................................................
(1)

(ii)

Petrol contains the elements carbon and hydrogen only.

Which two of the substances in the diagram are formed when petrol burns? 1 ................................................................................................................... 2 ..................................................................................................................
(2) (Total 5 marks)

8.

(a)

Crude oil consists of a large number of different compounds. Most of these compounds are alkanes. (i) Explain how fractional distillation separates crude oil. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................
(2)

(ii)

What are alkanes? .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................
(2)

(iii)

Alkanes, such as methane, CH4, are used as fuels. Write a balanced chemical equation for the complete combustion of methane in oxygen. ..........................................................................................................................
(3)

(b)

Alkenes can be made by cracking large alkane molecules. (i) Explain how the cracking process is carried out. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................
(2)

(ii)

Give a chemical test which would show the difference between an alkene and an alkane. Test .................................................................................................................. Result of test .................................................................................................... ..........................................................................................................................
(2)

(c)

Alkenes, such as ethene, can be made into polymers. (i) Complete the following to show how the ethene molecules bond to form part of a polymer.
H C H H C H H C H H C H H C H H C H

(1)

(ii)

Name the polymer formed from ethene. ..........................................................................................................................
(1)

(iii)

Explain one important problem caused by the everyday use of this polymer. .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................
(2) (Total 15 marks)

Summary questions plant oils
Complete all the following questions about vegetable oils and related topics. 28 Cross out the wrong alternatives in the true/false statements below. bb) Unsaturated oils have double bonds in them. cc) Oils are removed from most plants using filtration. blue. water. ff) Solid fats tend to be solids at room temperature. gg) Emulsions are mixtures of liquids. hh) The word immiscible means the same as insoluble. ii) jj) Milk is an emulsion of fats and water. E-numbers are substances which are all harmful. true/false true/false true/false true/false true/false true/false true/false true/false true/false true/false

dd) Unsaturated oils can be detected by bromine water turning from orange to ee) Oils can be used for cooking because their boiling point is higher than that of

kk) An example of a type of E-number is an emulsifier. 29 Fill in the gaps in the following paragraph.

Oils can be extracted from plants using ___________________. Sometimes steam ________________________ is used because it does not raise the temperature too far. This does not change the oil. An example of an oil extracted using this method is ______________ oil which is used in perfumes and bath products. Vegetable oils are very important in our diets because they contain a great deal of _____________. Many vegetable oils contain C=C bonds and are therefore called __________________________ oils. When these are shaken with bromine ____________ they change it from __________ in colour to _________________. Unsaturated fats are supposed to be better for us because they do not form so much ___________________________ in our bodies. 30 Cross out the wrong alternatives in the following paragraph. Animal fats have higher levels of saturated/unsaturated fats in them than plant fats. This is because the attractive/repulsive forces between the saturated/unsaturated fat molecules are stronger/weaker than those between saturated/unsaturated molecules. People are being told to eat less saturated/unsaturated fats because saturated fats lead to higher levels of alcohol/cholesterol in the blood which can lead to heart/brain disease. Therefore the eating of meat, especially lots of white/red meat, is being discouraged. This is because of its association with heart/brain disease. 31 Cross out the wrong alternatives in the following paragraph. Vegetable oils and fats are used for cooking because they have higher/lower boiling points than water. Therefore the food can be raised to a lower/higher temperature and the food is cooked more slowly/quickly. The texture/name of the food also changes and different physical/chemical changes take place. Sometimes oils are not convenient to use as liquids/gases because we need to spread/smell them more easily. To make them into solids/gases they are reacted with oxygen/hydrogen in the presence of a catalyst in a process called hydrogenation/oxygenation. Vegetable oils can be made into butter/margarine in this way.

32 Fill in the gaps in the following paragraph. E-numbers are substances that are added to food to make it __________________ its properties. There are ______ types of food additives. ________________ make the food last longer. Antioxidants have a similar effect because they help to stop the food reacting with ________________. Emulsifiers improve the ______________ of the food. Flavourings increase the particular taste of a food. A good example is __________________ glutamate which is often added to __________________ food. Many people are worried about the use of E-numbers in food because some additives lead to _________________ in children. Colourings are added to food to make it more _______________ to look at. These substances can be separated or identified using ___________________. Emulsifiers allow ______________ liquids to mix and form one phase.

Traffic light self-assessment.
For each of the following topics assess whether you: Red = Do not understand. Amber = Are not sure. Green = Understand. 33 Oils are extracted from plants using distillation. Red/amber/green 34 We can test for double bonds in a molecule using bromine water. Red/amber/green 35 Fat is a very good source of energy. Red/amber/green 36 Margarine and other spreads can be made from vegetable oils by hydrogenation. Red/amber/green 37 Vegetable oils are useful for cooking because they have a high boiling point. Red/amber/green 38 When foods are cooked using vegetable oils, the cooked food has changed chemically. Red/amber/green 39 An emulsion is formed when immiscible liquids are allowed to mix by using an emulsifier. Red/amber/green 40 E-numbers are added to foods to improve their properties. Red/amber/green 41 There are six different types of additive. Red/amber/green

42 These six types are as follows: A B C D E F Colours. Red/amber/green Preservatives. Red/amber/green Antioxidants. Red/amber/green Emulsifiers, stabilisers and thickeners. Red/amber/green Acidity regulators. Red/amber/green Flavourings.

Red/amber/green 43 There is a lot of controversy about the use of additives in foods. Red/amber/green

Products from oil
1 This question is about polymers. Match the words A, B, C and D with the spaces 1 to 4 in the sentences. A B C D transparent .................... light sensitive .................... thermosetting .................... thermosoftening ....................

A plastic that can be remoulded is made from a ……1…… polymer. The plastic used to make a handle for a grill pan would be best made from a polymer that is ……2…… The polymers used to make food wrappings for use in a supermarket are best if they are ……3…… Some new types of sticking plaster can be removed easily because they are made from ……4……polymers. 2 Match the words A, B, C and D with the descriptions 1 to 4 in the table. A bromine ………. (4)

B C D 1 2 3 4 3

butene ………. poly(ethene) ………. propane ………. Description An alkane A polymer Used to make polymers Used to test for unsaturation (4)

Match the words A, B, C and D with the spaces 1 to 4 in the sentences about plastics. A B C D chemical bonds .................... intermolecular forces .................... monomers .................... polymers ....................

Plastics are made of many ……1…… joined together in long chains to form …… 2…… . In thermosoftening plastics the long chains are held together by ……3… … which are overcome by heating. In thermosetting plastics ……4…… form between the long chains when they are heated and the plastic sets hard. (4) 4 An alkane, C12H26, was cracked. The reaction that took place is represented by the equation: C12H26 → C6H14 + C4H8 + …… (a) The formula of the missing compound is … A C CH4 C2H6 B D C2H4 C3H8

(b) The compound C4H8 is … A C an alkane a poly(alkane) B D an alkene a poly(alkene)

(c) Addition polymers can be made from … A C C12H26 C4H8 B D C6H14 C2H6

(d) The structure of C4H8 could be …

(4) 5 Read the passage about ‘Slime’ and use the information to help you answer the questions. ‘Slime’ has some of the properties of a liquid and some of the properties of a solid. It can be poured but it bounces if dropped on the floor. ‘Slime’ is made by mixing a solution containing a polymer called PVA with borax. When the substances are mixed the borax forms cross-links between the polymer chains. Some of the cross-links are chemical bonds and some are intermolecular forces involving water molecules. Lots of water molecules are held between the polymer chains and these give ‘Slime’ its flexibility and fluidity. (a) Describe a molecule of a typical polymer. .......................................................................................................................... .......................................................................................................................... (2) (b) Suggest why ‘Slime’ has the properties of both a solid and a liquid. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... (3) (c) Suggest one method that you could use to modify the properties of ‘Slime’. .......................................................................................................................... (1) (d) A student tested different types of ‘Slime’ by measuring how far they stretched before they broke. (i) What was the independent variable in the investigation? .................................................................................................................... (1) (ii) What type of variable was the dependent variable – categoric, ordered, discrete or continuous?

.................................................................................................................... (1)

Polymers past paper questions
1. Poly(ethene) is a long-chain saturated hydrocarbon. The formula for part of the polymer chain is:

H C H
(a)

H C H

H C H

H C H

H C H

H C H

H C H

Write the structural formula of the small molecule from which poly(ethene) is made.

(2)

(b)

Saturated hydrocarbons, such as propane, are fuels. Write a balanced equation for the complete combustion of propane, C3H8. ............................ + ............................ → ............................ + .............................
(3) (Total 5 marks)

2.

The diagram shows an apparatus that can be used to carry out cracking reactions in a laboratory.

Paraffin soaked onto mineral wool Aluminium oxide or broken porcelain Delivery tube

Warm

Strong heat

B

A

Cold water

(a)

Why is aluminium oxide or broken porcelain used? ..................................................................................................................................... .....................................................................................................................................
(1)

(b)

Paraffin contains decane. The cracking of decane can be represented by the equation below. A decane molecule is split into two smaller molecules. Complete the equation by adding the formula of the other product. C10H22 (l) → .................... (l) + C2H4 (g) decane
(1)

(c)

Would you expect C2H4 molecules to collect at position A or B shown on the diagram? Position ............................ Explain your answer. ..................................................................................................................................... .....................................................................................................................................
(1)

(d)

Cracking reactions involve thermal decomposition. What is meant by thermal decomposition? ..................................................................................................................................... .....................................................................................................................................

..................................................................................................................................... .....................................................................................................................................
(2)

(e)

Explain, as fully as you can, why cracking is used in the oil industry. To gain full marks in this question you should write your ideas in good English. Put them into a sensible order and use the correct scientific words. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................
(3)

(f)

The cracking reaction produces a mixture of products. The mixture contains hydrocarbons with different boiling points. Suggest a method of separating this mixture. ..................................................................................................................................... .....................................................................................................................................
(1) (Total 9 marks)

3.

Modem window frames are often made from uPVC which contains the plastic poly(chloroethene).

WONDERFUL WINDOWS
Replace your old wooden windows with our super high quality uPVC windows!
NO PAINTING - MAINTENANCE FREE

(a)

State why plastic window frames need no painting or maintenance. ........................................................................................................................... .......... ........................................................................................................................... ..........
(1)

(b)

Poly(chloroethene) is a polymer formed by the addition polymerisation of

chloroethene. (i) Chloroethene is an unsaturated molecule. Why is this molecule said to be unsaturated? .......................................................................................................................... ..........................................................................................................................
(1)

(ii)

Complete the diagram to represent how poly(chloroethene) is formed from chloroethene.

H n C Cl

H C H
(3)

(iii)

Explain what is meant by the term polymerisation. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................
(2)

(iv)

Why is this an addition polymerisation? .......................................................................................................................... ..........................................................................................................................
(1) (Total 8 marks)

4.

Propane and ethene are both important hydrocarbons.

propane formula C3H8 H structure H

ethene

H C C H

(a)

Complete the table by adding the formula of the ethene molecule and the structure of the propane molecule.
(2)

(b)

Propane is a fuel used in camping stoves. When propane burns there is an exothermic reaction. (i) What is meant by the term “exothermic reaction”? .......................................................................................................................... ..........................................................................................................................
(2)

(ii)

Balance the chemical equation for the reaction which takes place when propane burns in a plentiful supply of air. C3H8 + _________ O2 → _________ CO2 + _________ H2O
(2)

(c)

Ethene can be changed into a plastic. The equation shown below represents the reaction in which ethene is polymerised.

H n C H
(i)

H C H

H C H

H C H n

What is the name of the plastic formed in this reaction? ..........................................................................................................................
(1)

(ii)

What type of polymerisation reaction is shown in the equation? ..........................................................................................................................
(1) (Total 8 marks)

5.

(a)

Propene and propane can be produced from crude oil. (i) A propene molecule (C3H6) can be represented by the structure shown below.

H C H

H C

H C H H

Draw a similar diagram to show the structure of a propane molecule (C3H8).

(1)

(ii)

Which molecule, propene or propane, is unsaturated? ..........................................................................................................................

Give a reason for your answer
.......................................................................................................................... ..........................................................................................................................
(1)

(b)

The equation below represents the polymerisation of propene.

H n C

H C

H C

H C

H CH 3
(i) Name the polymer produced by this reaction.

H CH 3 n

..........................................................................................................................
(1)

(ii)

Explain the meaning of the term polymerisation. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................
(2)

(iii)

Describe the problems caused by the everyday use of this polymer. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................
(3) (Total 8 marks)

Summary questions plant oils
Complete all the following questions about vegetable oils and related topics. 44 Cross out the wrong alternatives in the true/false statements below. ll) Unsaturated oils have double bonds in them. true/false true/false true/false true/false true/false true/false true/false true/false true/false true/false mm)Oils are removed from most plants using filtration. blue. water. pp) Solid fats tend to be solids at room temperature. qq) Emulsions are mixtures of liquids. rr) The word immiscible means the same as insoluble. ss) Milk is an emulsion of fats and water. tt) E-numbers are substances which are all harmful. uu) An example of a type of E-number is an emulsifier. 45 Fill in the gaps in the following paragraph. Oils can be extracted from plants using ___________________. Sometimes steam ________________________ is used because it does not raise the temperature too far. This does not change the oil. An example of an oil extracted using this method is ______________ oil which is used in perfumes and bath products. Vegetable oils are very important in our diets because they contain a great deal of _____________. Many vegetable oils contain C=C bonds and are therefore called __________________________ oils. When these are shaken with bromine ____________ they change it from __________ in colour to _________________. Unsaturated fats are supposed to be better for us because they do not form so much ___________________________ in our bodies. 46 Cross out the wrong alternatives in the following paragraph. Animal fats have higher levels of saturated/unsaturated fats in them than plant fats. This is because the attractive/repulsive forces between the saturated/unsaturated fat molecules are stronger/weaker than those between saturated/unsaturated molecules. People are being told to eat less saturated/unsaturated fats because saturated fats lead to higher levels of alcohol/cholesterol in the blood which can lead to heart/brain disease. Therefore the eating of meat, especially lots of white/red meat, is being discouraged. This is because of its association with heart/brain disease. 47 Cross out the wrong alternatives in the following paragraph. Vegetable oils and fats are used for cooking because they have higher/lower boiling points than water. Therefore the food can be raised to a lower/higher temperature and the food is cooked more slowly/quickly. The texture/name of the food also changes and different physical/chemical changes take place. Sometimes oils are not convenient to use as liquids/gases because we need to spread/smell them more easily. To make them into solids/gases they are reacted with oxygen/hydrogen in the presence of a catalyst in a process called hydrogenation/oxygenation. Vegetable oils can be made into butter/margarine in this way.

nn) Unsaturated oils can be detected by bromine water turning from orange to oo) Oils can be used for cooking because their boiling point is higher than that of

48 Fill in the gaps in the following paragraph. E-numbers are substances that are added to food to make it __________________ its properties. There are ______ types of food additives. ________________ make the food last longer. Antioxidants have a similar effect because they help to stop the food reacting with ________________. Emulsifiers improve the ______________ of the food. Flavourings increase the particular taste of a food. A good example is __________________ glutamate which is often added to __________________ food. Many people are worried about the use of E-numbers in food because some additives lead to _________________ in children. Colourings are added to food to make it more _______________ to look at. These substances can be separated or identified using ___________________. Emulsifiers allow ______________ liquids to mix and form one phase.

Traffic light self-assessment.
For each of the following topics assess whether you: Red = Do not understand. Amber = Are not sure. Green = Understand. 49 Oils are extracted from plants using distillation. Red/amber/green 50 We can test for double bonds in a molecule using bromine water. Red/amber/green 51 Fat is a very good source of energy. Red/amber/green 52 Margarine and other spreads can be made from vegetable oils by hydrogenation. Red/amber/green 53 Vegetable oils are useful for cooking because they have a high boiling point. Red/amber/green 54 When foods are cooked using vegetable oils, the cooked food has changed chemically. Red/amber/green 55 An emulsion is formed when immiscible liquids are allowed to mix by using an emulsifier. Red/amber/green 56 E-numbers are added to foods to improve their properties. Red/amber/green 57 There are six different types of additive. Red/amber/green

58 These six types are as follows: A B C D E F Colours. Red/amber/green Preservatives. Red/amber/green Antioxidants. Red/amber/green Emulsifiers, stabilisers and thickeners. Red/amber/green Acidity regulators. Red/amber/green Flavourings.

Red/amber/green 59 There is a lot of controversy about the use of additives in foods. Red/amber/green

Plant oils
1 The energy values of chips depend on their fat content. Match the energy values A, B, C and D with the numbers 1 to 4 in the table. A 687 kJ/100 g ………. B 796 kJ/100 g ………. C 1001 kJ/100 g ………. D 1174 kJ/100 g ………. Description of type of chips Fat content (g/100 g) 1 2 3 4 Fish and chip shop, fried in blended oil French fries from burger outlet Homemade fried in blended oil Oven chips, frozen, baked 12.4 15.5 6.7 4.2 (4) 2 Match the words A, B, C and D with spaces 1 to 4 in the sentences. A B C D cooking oils .................... emulsifiers .................... emulsions .................... hydrogenated oils ....................

Mayonnaise and salad dressings are ……1…… that are made by mixing oil and vinegar with other ingredients such as egg yolk. In mayonnaise the egg yolk contains ……2……that stop the oil and water separating. Vegetable oils can be converted into ……3…… by reacting with hydrogen and a catalyst. Biodiesel is a fuel that can be made from waste ……4…… . 3 (4)

The table on the next page gives some information about four different vegetable oils. Smoke point is the temperature at which the oil begins to smoke when heated. Match descriptions A, B, C and D with numbers 1 to 4 in the table. A B C D The oil that contains the most monounsaturated fat. .................... The oil that reacts with the largest volume of bromine water. .................... The oil with the highest melting point. .................... The oil with the widest range of smoke point. .................... Type of oil 2 3 Olive Sunflower oil oil 14.3 12.0 73.0 20.5

Saturated fat (%) Monounsaturated fat (%) Polyunsaturated fat (%) Melting point (°C) Smoke point (°C)

1 Corn oil 14.4 29.9

4 Rapeseed oil 6.6 59.3

51.3

08.2

63.3

29.3

–15

–12

–18

5 230–240 (4)

229–268

204–210

229–252

4

Use the table of types of chips in question 1 to help you answer these questions. (a) Why do chips contain fat? .......................................................................................................................... (1) (b) Why do French fries contain most fat? .......................................................................................................................... (1) (c) Why do oven chips contain least fat? .......................................................................................................................... .......................................................................................................................... (2) (d) Why do all chips have a golden brown colour, but boiled potatoes remain white? .......................................................................................................................... .......................................................................................................................... (2) (e) (i) How would you display the data in the table? .................................................................................................................... (1) (ii) Explain your answer to part (i).(1) .................................................................................................................... (1)

5

Virgin olive oil is extracted by mechanical methods that do not modify its properties. If the temperature during extraction does not exceed 27°C the oil can be labelled as ‘cold pressed’. Any olive oil that remains in the pressed pulp can be extracted by dissolving it in a solvent. The solvent is removed from the oil by evaporation. This type of oil is called pomace oil. (a) Why is it important that the temperature does not exceed 27°C during extraction? .......................................................................................................................... .......................................................................................................................... (2) (b) Suggest why some people prefer virgin olive oil to pomace oil.

.......................................................................................................................... .......................................................................................................................... (2) 6 Some students made a solution of the colours in a soft drink. Describe how you could use paper chromatography to show how many colours were in the solution. ................................................................................................................................. ................................................................................................................................. ................................................................................................................................. ................................................................................................................................. (4)

Summary questions Earth and Atmosphere
60 Cross out the wrong alternatives in the following statements. vv) The Earth’s centre is called the mantle. ww)The Earth’s crust consists of interlocking plates. xx) The Earth’s core is mainly made up of nickel and iron. yy) Another name for the crust is the lithosphere. plates. true/false true/false true/false true/false true/false true/false bbb)Below the crust lies the mantle. ccc)The plates are moved by atmospheric currents above the crust. ddd)Earthquakes occur when plates rub against each other. eee)Magma is molten rock. 61 Cross out the wrong alternatives in the following paragraphs. The Earth’s atmosphere has evolved over thousands/billions of years. The early atmosphere contained lots of carbon dioxide/oxygen and other gases. It also contained lots of ice/water vapour. When the Earth cooled down, this condensed/froze to liquid water and formed the oceans. Some of the earliest plants/animals on Earth were blue–green roses/algae and these carried out photosynthesis/combustion. This process produced oxygen/carbon dioxide. This gas reacted with substances such as metals to form metal sulfides/oxides. When these reactions were finished, the oxygen/carbon dioxide built up in the atmosphere. The ozone layer formed and stopped too much ultraviolet/visible light hitting the Earth. Animals were able to evolve and carry out respiration/photosynthesis. A balance was true/false true/false true/false true/false

zz) Geological phenomena mainly occurs at the boundaries of the tectonic aaa)Tectonic plates are moved by atmospheric currrents above the crust.

obtained and now the oxygen level is about one-half/one-fifth of the air in the atmosphere. 62 Fill in the gaps in the following paragraphs. In the presence of light, plants carry out ____________________. In this process ________________ ______________ gas and water react to form glucose and _______________ gas. Photosynthesis takes in energy and therefore is an ________________ic process. Animals carry out __________________ in order to produce energy. This is an _______________ic process. It uses up _______________ gas and produces ______________ _______________ gas. Carbon dioxide is also produced when fossil _______________ are burned in air. This is speeding up _______________ warming.

Traffic light self-assessment
For each of the following topics assess whether you: Red = Do not understand. Amber = Are not sure. Green = Understand. 1 The Earth has four layers. Red/amber/green 2 The Earth’s crust is not continuous. Red/amber/green 3 The Earth’s crust is made up of tectonic plates. Red/amber/green 4 Examples of geological phenomena are earthquakes but there are others. Red/amber/green 5 Many geological phenomena occur at the boundaries of the plates. Red/amber/green 6 The early atmosphere of the Earth did not contain oxygen. Red/amber/green 7 Blue–green algae produced oxygen using photosynthesis. Red/amber/green 8 Carbon dioxide levels are lowered by photosynthesis and dissolving. Red/amber/green 9 Carbon dioxide is denser than air. Red/amber/green 10 Carbon dioxide levels are rising because we are burning fossil fuels. Red/amber/green

The changing world
1 Match words A, B, C and D with the numbers 1 to 4 in the table. A B C D atmosphere .................... core .................... crust .................... mantle .................... Description Almost entirely solid, but can flow very slowly Contains mainly the elements nitrogen and oxygen Has an average thickness of about 6 km under oceans and 35 km under continents Part liquid and part solid, with a radius of about 3 500 km

1 2 3 4

(4) 2 Match words A, B, C and D with the spaces 1 to 4 in the sentences. A B C D believed .................... dismissed .................... produced .................... published ....................

In 1912 Alfred Wegener ……1…… a theory that a single land mass had split apart into continents that moved to their current positions. At the time geologists ……2…… that the continents moved up and down – not sideways. Wegener’s theory was ……3…… by geologists because he could not explain how the continents moved. In 1944 an English geologist explained that heat from radioactivity ……4…… convection currents strong enough to move continents. (4) 3 Match words A, B, C and D with spaces 1 to 4 in the sentences. A B C D ammonia .................... carbon dioxide .................... noble gases .................... oxygen ....................

The Earth’s early atmosphere consisted mainly of ……1…… with some nitrogen, water vapour, methane and ……2…… . The Earth’s atmosphere now contains 78% nitrogen, 21% ……3……, about 1% ……4……. and 0.04% carbon dioxide. 4 This question is about three of the noble gases, helium, neon and argon. (a) Why is helium used in balloons and airships rather than hydrogen? .......................................................................................................................... .......................................................................................................................... (2) (b) Explain how argon allows you to use an electric light bulb for many hours. .......................................................................................................................... .......................................................................................................................... (2) (4)

(c) Explain how neon is used for advertising. .......................................................................................................................... .......................................................................................................................... (2)

5

The graph shows the percentage of carbon dioxide in the atmosphere in recent years.

(a) (i) Could the ‘percentage’ of carbon dioxide in the atmosphere be described as a categoric, discrete or continuous variable? .................................................................................................................... (1) (ii) There is considerable variation in the percentage of carbon dioxide within each 5 year period. What do we call the line that ‘smooths out’ these variations on the graph? .................................................................................................................... (1) (b) By how much has the percentage of carbon dioxide increased from 1960 to 2005? .................................................................................................................... (1) (c) What is this increase as a percentage of the 1960 figure? .................................................................................................................... (1) (d) Suggest two reasons for this increase. .......................................................................................................................... .................................................................................................................... (2) (e) What natural processes remove carbon dioxide from the atmosphere?

.......................................................................................................................... .......................................................................................................................... .................................................................................................................... (3) (f) Why should we be concerned about the increase in carbon dioxide? .......................................................................................................................... .................................................................................................................... (2)

Earth and Atmosphere past paper questions
1. Wax is a fuel. A young child watched a candle burning and wondered where the wax had gone.

(a)

Complete the sentence below. When wax burns, energy is released as ......................................................................
(1)

(b)

Why does the wax disappear as it burns? .................................................................................................................................... ....................................................................................................................................
(1) (Total 2 marks)

2.

(a)

Air is a mixture of gases. The pie chart shows the percentages, by volume, of the main gases in dry air. Complete the chart by adding the names of these three gases.

78% 1%

(i) ..................................

(ii) ..................................

21%

(iii) ..................................

(3)

(b)

Complete each of the four spaces in the sentences by choosing the best word from the box.

condenses melts

condensing sea

evaporates trees

evaporating vapour

The air in the atmosphere above this country always contains ................................ . Most of this is the result of water ................................ from the surface of the ................................. . Some of it ................................ to form millions of tiny drops of water in clouds.
(4)

(c)

Thousands of millions of years ago the Earth’s early atmosphere was formed. Complete the following sentence. The carbon dioxide in this early atmosphere probably came from ........................... .................................................................................................................................. .
(1) (Total 8 marks)

3.

(a)

The diagram shows the Earth’s layered structure. Name parts (i) and (ii).

(2)

(b)

The bar chart shows the composition of a sample of dry air from the Earth’s atmosphere. Name the three gases shown in the bar chart.

100 (i) .................................................. 80

60 Percentage 40 (ii) .................................................. 20 (iii) .................................................. 0
(c) The Earth’s crust is a set of slow-moving plates. There are fold mountains at some places where the plates meet. Give examples of two other types of geological features or activities which usually occur at these places. 1 .................................................................................................................................. 2 ..................................................................................................................................
(2) (3)

(d)

One carbon compound is methane. Its chemical formula is CH4. (i) What is the name of the element which is combined with carbon in methane? ...........................................................................................................................
(1)

(ii)

Complete the word equation for the chemical reaction which usually takes place when methane burns. methane +..................................→ carbon dioxide + water
(1) (Total 7 marks)

4.

The bar chart shows the composition of the Earth’s atmosphere today, and as it was billions of years ago.

BILLIONS OF YEARS AGO 100 90 80 70 % 60 composition of 50 atmosphere 40 30 20 10 others Carbon dioxide Carbon dioxide

TODAY

nitrogen

oxygen

others

0

(a)

Use information from the bar chart to describe how the atmosphere today is different from the atmosphere of billions of years ago. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................
(2)

(b)

Describe the processes which have brought about the changes in the proportions of these gases in the air over billions of years. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................
(4) (Total 6 marks)

5.

(a)

Apart from water vapour, two gases account for about 99% of the present atmosphere of our planet. What are the names of these gases? .......................................................... and ........................................................
(1)

(b)

Scientists now have evidence that, over three billion years ago, our planet’s atmosphere was mostly a mixture of water vapour, carbon dioxide, methane and ammonia. Since then the mixture has gradually changed. (i) Suggest why there is now less water vapour in the atmosphere. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................
(2)

(ii)

Suggest why there is now less carbon dioxide in the atmosphere. .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................
(2)

(c)

The following information suggests that the continents of Africa and South America were once joined together but then began to move apart. Fossilised remains of a large fern-like plant called Glossopteris have been found in the rocks of the Carboniferous period in both Africa and South America. Fossilised remains of a freshwater reptile called Mesosaurus have been found in the rocks of the Permian period in both Africa and South America. No fossils of identical organisms have been found in the rocks of the Jurassic or the Cretaceous period in Africa or South America. The following table gives the names of some of the periods in our planet’s geological history. Start of the period millions of years ago 2 65 136 190 225 280 345 395 435 500 570 (i) Name of the period Quaternary Tertiary Cretaceous Jurassic Triassic Permian Carboniferous Devonian Silurian Ordovician Cambrian

Use this information to suggest when Africa and South America began to move apart. About ......................................................... million years ago.
(1)

(ii)

What conditions were necessary for Africa and South America to move apart? .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................
(3) (Total 9 marks)

6.

For 200 million years the proportions of the different gases in the atmosphere have been much the same as today. Over the past 150 years the amount of carbon dioxide in the atmosphere has increased from 0.03% to 0.04%. (a) Describe how carbon dioxide is released into the atmosphere: (i) by human and industrial activity; ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................
(2)

(ii)

from carbonate rocks by geological activity. ........................................................................................................................... ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................
(2)

(b)

Explain how the seas and oceans can decrease the amount of carbon dioxide in the atmosphere. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (3)

(c)

(i)

Give one reason why the amount of carbon dioxide in the atmosphere is increasing gradually. ........................................................................................................................... ...........................................................................................................................
(1)

(ii)

Give one effect that increasing levels of carbon dioxide in the atmosphere may have on the environment. ........................................................................................................................... ...........................................................................................................................
(1) (Total 9 marks)

7.

(a)

The air is a mixture of many gases. Some of these gases are shown in the table. Name nitrogen oxygen argon carbon dioxide (i) Which of these gases are: elements ........................................................................................................... compounds .......................................................................................................
(2)

Chemical formula N2 O2 Ar CO2

(ii)

Give one important use of nitrogen. ..........................................................................................................................
(1)

(iii)

Put a circle around the correct average percentage of carbon dioxide in the air. 0.03% 0.9% 78%
(1)

(iv)

The amount of carbon dioxide in the air varies from place to place.

The amount of carbon dioxide in the countryside is often lower than in

towns and cities. Explain why. ........................................................................................................................... ........................................................................................................................... ...........................................................................................................................
(2)

(b)

An experiment to find how much oxygen is in the air is shown.

Copper 100 75 100 100 cm 3 of air
3

25 Heat

50

The 100 cm of air was pushed from one syringe to the other over hot copper. This was repeated many times. (i) Complete the word equation to show how oxygen was removed from the air. copper + oxygen → ........................................................ (ii) The surface of the copper changed colour when it was heated in air. The colour before heating was .......................................... . The colour after heating was .......................................... .
(2) (1)

(iii)

The experiment showed that there was 21% oxygen in the air. What volume of the air was left in the syringe at the end of the experiment? Volume of the air left = ............................................................................ cm
3

75

50

25

(1) (Total 10 marks)

St Olave's and St Saviour's Grammar School

Atomic Structure past paper questions

1.

The diagram shows the structure of a lithium atom.

KEY
+ = proton

= electron
+ + +

(a)

(i) (ii)

What is represented by

.................................................................................

+ + What is represented by + ...........................................................................
(2)

(b)

What is the symbol for lithium? ................................................................................
(1) (Total 3 marks)

2.

There are millions of different substances that make up our world. All these substances are made from chemical elements. (a) What is an element? ..................................................................................................................................... .....................................................................................................................................
(1)

(b)

Many substances are compounds. What is a compound? ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .....................................................................................................................................
(2) (Total 3 marks)

3.

The diagram represents an atom. Choose words from the list to label the diagram. electron ion neutron nucleus

proton
(Total 3 marks)

Oils, Earth and atmosphere
Science A
1 Match the polymers A, B, C and D with the numbers 1 to 4 in the table. A B C D high density poly(ethene) ………. low density poly(ethene) ………. poly(chloroethene) ………. poly(propene) ………. Density (g/cm3) 0.90 0.92 0.96 1.30 Monomer C3H6 C2H4 C2H4 C2H3Cl (4 marks) 2 Alfred Wegener first suggested his theory of continental drift in 1915. He suggested that the continents had once been a single large land mass that had split apart. He showed that fossils and rocks were similar on the parts of America and Africa that fitted together. He produced a lot of evidence to support his theory but other scientists did not accept his ideas for over 50 years. (a) One of the main reasons why other scientists did not accept his ideas was … A America and Africa are too far apart.

1 2 3 4

B C D

Fossils are similar all over the Earth. He could not explain how the continents moved. He had no evidence that the continents were moving.

(b) Geologists did not like his ideas because … A B C D they could not understand his fossil evidence. they did not know enough about the rocks of Africa and America. they did not like German scientists. they would have to change all their own long established ideas.

(c) What new evidence was found in the 1960s? A B C D Land bridges had existed between the continents. The sea floor was spreading on either side of deep ocean ridges. The polar ice-caps were shown to be melting. The Earth had been shrinking since it had been formed.

(d) What new theory was developed using Wegener’s ideas? A B C D convection currents plate tectonics radioactive decay seismic activity (4 marks)

Science B
1 Read the information in the box and use it to help you to answer the questions. Smart polymers can be used to switch enzymes on and off. The polymers are described as ‘smart’ because they alter their properties when conditions such as light, temperature or acidity change. Tiny smart polymer chains are attached to enzymes next to the active sites. The chains extend or contract depending on the conditions and block or unblock the site. This switches the enzyme off or on. One application already in use is for drugs that need to remain inactive until they reach a particular place in the body. (a) What is a polymer? .......................................................................................................................... .......................................................................................................................... (2 marks)

(b) Why are the polymers in the article ‘smart’? .......................................................................................................................... .......................................................................................................................... (2 marks) (c) Suggest another application for smart polymers that is not mentioned in the article. .......................................................................................................................... (1 mark) 2 Read the information in the box and use it to help you to answer the questions. Many plant oils are drying oils, which restricts their use as fuels. Drying happens when double bonds in the molecules are oxidised and form cross-links so the oil polymerises into a plastic-like solid. The process is accelerated at high temperatures and engines quickly become gummed up. Oils with high iodine values have more double bonds. An iodine value of less than 25 is required if the oil is to be used in unmodified diesel engines. (a) What is a drying oil? .......................................................................................................................... .......................................................................................................................... (2 marks) (b) In what way are the polymers formed like thermosetting plastics? .......................................................................................................................... (1 mark) (c) Suggest why drying oils are used in oil paints. .......................................................................................................................... .......................................................................................................................... (2 marks) (d) Describe how you could find the volume of iodine solution that reacted with a plant oil. Include how you would make your results as precise as possible. .......................................................................................................................... .......................................................................................................................... ..........................................................................................................................

.......................................................................................................................... (4 marks) (e) Iodine values can be lowered by hydrogenation. (i) How could this be done? .......................................................................................................................... .......................................................................................................................... (2 marks) (ii) Give one disadvantage of hydrogenation. .......................................................................................................................... (1 mark)