Surname Centre No. Initial(s) Paper Reference 4 3 3 5 Candidate No. 2 H Signature Paper Reference(s) 4335/2H Examiner’s use only London Examinations IGCSE Team Leader’s use only Chemistry Paper 2H Higher Tier Tuesday 6 November 2007 – Morning Time: 2 hours Question Leave Number Blank 1 2 3 4 5 Materials required for examination Nil Items included with question papers Nil 6 7 8 9 Instructions to Candidates In the boxes above‚ write your centre number‚ candidate number‚ your surname
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(including your name above) it will expand as you write. Activity 1 1-1: Insert the chemical symbol in the answer blank for each of the following elements. ____ 1. oxygen ____ 2. carbon ____ 3. potassium ____ 4. iodine ____ 5. hydrogen ____ 6. nitrogen ____ 7. calcium ____ 8. sodium ____ 9. phosphorus ____ 10. magnesium ____ 11. chlorine ____ 12. iron 1-2: In the space below‚ list the chemicals above from the MOST abundant in the human body to the LEAST abundant
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Self-assessment practice tests Test 1 – Material from Chapters 2–4 | 45 minutes 1 The kinetic theory suggests different arrangements for the atoms or molecules in the three states of matter. The diagrams below show how evidence suggests the particles are arranged in the three states of matter. 1 2 3 What are the three states shown? 1 A B C D 2 gas liquid solid liquid 2 liquid gas liquid solid 3 solid solid gas gas The graph shows the heating curve for a metal that is solid at room temperature (25
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mass stars‚ begin to form from clouds of gas and dust in space. They both begin as a protostar and eventually become dense enough to cause hydrogen fusion within them; placing them both on the main-sequence. The only difference is high mass stars are able to get through this process quicker due to their increased gravity from their higher mass. Once the hydrogen is used up‚ like low mass stars‚ high mass stars start to form shells of heavier elements up to carbon. Then unlike low mass stars they are
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balance across the plant. What is Ammonia Ammonia (NH3) is a stable compound and is used as a starting material for the manufacture of many important nitrogen compounds and can also be directly used as fertilisers. It is produced by reacting hydrogen and nitrogen. It is a colourless gas with a sharp odour. The boiling point is -33.35oC and its freezing point is -77.7oC.1 Care must be taken when handling ammonia as can cause deep burns in the skin; irritation in the eyes and nose and when inhaled
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the following molecules: water‚ ammonia‚ carbon dioxide‚ fluorine‚ methane‚ ethane 2. Write the formulas and draw the two-dimensional structures in the table. 3. Chose one color candy to represent each atom of an element (e.g.‚ red jelly bean = hydrogen). Create a key that identifies each element. 4. Use the candy‚ toothpicks‚ and/or twist ties to construct a three- dimensional model of each of the aforementioned molecules. 5. Draw‚ as accurately as possible‚ each model in the table. 6. Answer
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assumed to be 1. It is best to begin with an element other than hydrogen or oxygen. These two elements often occur more than twice in an equation. 5. Check each atom or polyatomic ion to be sure that the equation is balanced. 6. Finally‚ make sure that all the coefficients are in the lowest possible ratio. Now let’s use these rules to balance the equation for the formation of water from hydrogen and oxygen. Example 3 When hydrogen and oxygen react‚ the product is water. Write a balanced
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smallest structure in this list that can be seen with an ordinary desk microscope? 1. 2. 3. 4. Cells. Cell nucleus. Atoms. Chain molecules‚ such as proteins. Atoms In our model of scale‚ remember that the BB represented an atom. Electrons Hydrogen Helium Neutrons Protons As a class‚ identify the atoms represented here and label the sub-atomic particles. Carbon OxygenPhosphorous Calcium What elements are represented here? Use the Periodic Table on the wall to identify these atoms. What
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through three features. The first is a loss of oxygen from a bond or loss of a bond to oxygen as in the case of carbon-oxygen double bond to a carbon-oxygen single bond. The second is the addition of hydrogen to a bond and thirdly‚ the replacement of a more electronegative atom with carbon or hydrogen. In redox reactions‚ the reductant (or reducing agent) loses electrons and is oxidized while the oxidant (or oxidizing agent) gains electrons and is reduced. The reducing agent transfers electrons to
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February‚ 2011 Due Date: 9th February‚ 2011 Title: Analysis of the Elements present in Organic Compounds Aims: To test the presence of Carbon‚ Hydrogen‚ Oxygen‚ Nitrogen and Sulfur in Organic Compounds Introduction: Organic Compounds can be considered as any compound containing carbon atoms covalently bonded with other atoms‚ usually hydrogen. Other atoms may include oxygen‚ nitrogen‚ sulfur…etc. They can be found in nature‚ since “organic” means present in‚ or derived from‚ plants and animals
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