How do you classify a change in a substance as physical or chemical? A physical change: * can be observed; * is reversible; * takes place when the form (state) of the substance changes without changing its chemical composition (the change does not affect the structure). A chemical change (reactions): * appears when one substance is transformed into another substance (which then becomes a new set of properties‚ thus a new substance); * can be observed (via change in color‚ smell
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Key Terms: Mineral- a naturally occurring‚ inorganic solid that has a crustal structure and a definite chemical composition Rock- a large mass of stone Organic- derived from living organisms Inorganic- not derived from living organisms Pure Substance- a form of matter that has a constant chemical composition and characteristic properties. It cannot be separated into its several components without breaking its chemical bonds. Element- a substance composed of a single kind of atom
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Module One: Grade Nine Topics Physical Change: This is a usually reversible change in which the form of matter is altered‚ but is not chemically changed to another substance. Melting an ice cube is an example of a physical change. The ice cube changes states: from a solid to a liquid (water). You can physically see this change. No new substance is formed: the matter in the liquid is the same as it was in the ice cube. It is reversible: you can freeze the liquid to turn it back to ice.
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Vocab: 2.1 Mass: Measure of amount of matter in an object Volume: Measure of space occupied by object Extensive property: property that depends on amount of matter in a sample i.e.: mass and volume Intensive property: Property that depends on the type of matter in a sample(not amount) i.e.: type of basketball (leather; inside‚ rubber; outside) Substance: Matter that has a uniform and definite composition Physical property: Quality or condition of a substance that can be observed without
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Mid-YEAR EXAMINATION REVIEW PACKAGE * Everything around us is considered matter. Everything with a mass and a volume is considered matter. * All matter is made of small invisible particles called atoms. * There are 92 different types of atoms in the universe. * Substances that are made up of one type of atom are called pure elements; therefore there are 92 pure elements in the universe. * Substances made up of more than one type of atom are called mixtures. * Mixtures
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Chemistry Atomic Structure: The Electron A myriad of trends occur on the periodic table‚ whether it is defined through the size of the atoms or the first ionization energy that may occur‚ many other trends can be found simply looking horizontally or vertically on to the table. As you look from left to right you can see that the reactivity of the elements increase‚ this is due to the number of electrons increasing on the shell. This also once you go down the table; the shells become further and
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Lesson 03.01: History of the Periodic Table •Explain how scientific observations led to the development of‚ and changes to‚ the periodic table. -Dmitri Mendeleev- first periodic table‚ organized 63 known elements according to properties‚ organized into rows and columns and wrote name‚ mass‚ and chemical properties on each -Julius Lothar Meyer- independently worked in Germany‚ similar to Mendeleev -Henry Gwyn Jeffreys Moseley- Worked with Ernest Rutherford‚ experimented with 38 metals‚ he found
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NSS Chemistry Part 15 Analytical Chemistry (Structural Questions) HKCEE and HKAL Past Paper Questions 1. HKCEE 1994 Q8b A student carried out some tests on an ionic compound X which was a white solid. The results obtained were summarized in the following flow diagram: (i) Based on the above information‚ deduce the cation and anion present in X. (ii) Describe how the flame test on X can be carried out in the laboratory. (6 marks) 1 2. HKCEE 1995 Q2 In each of the following
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1) What is the purpose of ice or cold water? To cool down the gas so that it condenses and turns into a liquid. 2) when the gas collecting tube is upside down‚ give a property of this gas. It is less dense than air. 3) Why is a pencil used in drawing the origin line in chromatography? If pen was used‚ it will dissolve giving colours and so‚ the experiment won’t be accurate. Pencil doesn’t interfere with the results. 4) When using ethanol‚ give a better apparatus arrangement‚ and why? Cover
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Brief Historical Development and Contributions of Chemistry for Modern Civilization Introduction: As defined by Oxford Dictionary‚ Chemistry is the scientific study of the structure of substances‚ how they react when combined or in contact with one another and how they behave under different conditions . In other words‚ Chemistry is the study of the materials and substances of the world in which we live. The materials‚ which make up the earth‚ sea and air‚ are called raw materials. These include
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