0620_s07_qp_2
A paper of Chemistry, 0620
Questions:
7
Year:
2007
Paper:
2
Variant:
0
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1
Use The structures of some elements and compounds are shown below. S S S S S S S S H H C H H H C H H H H C H N H H H Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb Pb Na+ Cl – Na+ Cl – Na+ Cl – Na+ Cl – Na+ Cl – Na+ Cl – Na+ Cl – Na+ Cl – Na+ Cl – Na+ Cl – A B C D E F Answer these questions using the letters A to F. Which structure is ethane? Which structure contains ions? Which structure is a gas that turns moist red litmus paper blue? Which structure is sodium chloride? Which structure is the main constituent of natural gas? Which two structures are organic compounds? Which two structures are elements? Examiner's Use Structure F is lead. What is the source of the small amount of lead present in the air? State an adverse effect of lead on health. Structure A is sulphur. Explain why burning fossil fuels containing sulphur is harmful to the environment.
1. States of matter  →  1.1. Solids, liquids and gases
3. Stoichiometry  →  3.1. Formulae
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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2
Use Clean air contains a number of different gases. State the names of the two gases which make up most of the air. A sample of air is drawn through the apparatus shown below. white copper sulphate limewater air to suction pump heated copper When the air is drawn through the apparatus, the lime water turns milky. Which gas turns lime water milky? The white copper sulphate turns blue. State the name of the substance which turns white copper sulphate blue. Oxygen is removed from the air by passing it over heated copper. Complete the equation for this reaction. 2Cu + → CuO Examiner's Use Pure air contains about 1% argon. In which Period of the Periodic Table is argon? State the name of the Group of elements to which argon belongs. Draw the electronic structure of argon. Why is argon used in lamps? An isotope of argon has a mass number of 40. Calculate the number of neutrons in this isotope of argon. A small amount of xenon is present in the air. A few compounds of xenon have been made in recent years. Calculate the relative molecular mass of xenon difluoride, XeF2. Examiner's Use The structure of another compound of xenon is shown below. Xe F F F F O Write the simplest formula for this compound of xenon. Describe the type of bonding in this compound.
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
6. Chemical reactions  →  6.4. Redox
8. The Periodic Table  →  8.1. Arrangement of elements
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3
Use Hydrogen is a fuel which can be obtained from water by electrolysis. Petrol is a fuel obtained by the fractional distillation of petroleum. Complete the equation for the burning of hydrogen. H2 + O2 → H2O Suggest why hydrogen is a renewable source of energy. When hydrogen is burnt, heat is given off. State the name of the type of reaction which gives off heat. Petrol is a mixture of alkanes. One of the alkanes in petrol is octane, C8H18. What products are formed when octane is completely burnt in air? Petrol is only one of the fractions obtained from the fractional distillation of petroleum. State the name of two other fractions obtained from the distillation of petroleum. Give a use for each of these fractions. fraction use fraction use Examiner's Use More petrol can be made by cracking less useful petroleum fractions. What do you understand by the term cracking? State two conditions needed for cracking. Alkenes can be formed by cracking. The simplest alkene is ethene. Draw a diagram to show the structure of ethene. Show all atoms and bonds.
11. Organic chemistry  →  11.3. Fuels
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4
Use Catalysts are often used in industry. What do you understand by the term catalyst? Which type of metals often act as catalysts? A student measured the volume of hydrogen gas produced when a few large pieces of zinc reacted with hydrochloric acid of concentration 2.0 mol / dm3. The hydrochloric acid was in excess. The results are given in the table. time / minutes volume of hydrogen / cm3 Plot a graph of volume of hydrogen against time on the axes below. Label the axes. Examiner's Use Copper ions catalyse the reaction between zinc and hydrochloric acid. On the axes above, sketch the line you would expect for the catalysed reaction. Label this line C. Explain why no more hydrogen is given off after 50 minutes. What would happen to the speed of the reaction if small pieces of zinc were used instead of large pieces, the concentration of hydrochloric acid was 1.0 mol / dm3? The equation for this reaction is Zn + 2HCl → ZnCl2 + H2 State the name of the salt formed in this reaction. Describe a test for hydrogen. test result
6. Chemical reactions  →  6.2. Rate of reaction
9. Metals  →  9.4. Reactivity series
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5
Use Some sunglasses are made from glass which darkens in bright sunlight. The glass contains tiny crystals of silver chloride and copper(chloride. In bright sunlight, in the presence of copper(chloride, the silver chloride breaks down to solid silver which darkens the glass. Ag++ e- → AgState the name of the particle with the symbol e-. Silver is a metal. State two physical properties which are characteristic of all metals. In bright sunlight, the copper(chloride in the sunglasses is converted to copper(chloride. What do the roman numerals (and (show in these copper compounds? Tick one box. the number of atoms of copper in the copper compounds the number of neutrons in the copper compounds whether the copper is in the solid, liquid or gaseous state the oxidation state of the copper in the copper compounds Describe a test for aqueous copper(ions. test result Give a common use of copper.
10. Chemistry of the environment  →  10.1. Water
4. Electrochemistry  →  4.1. Electrolysis
12. Experimental techniques and chemical analysis  →  12.5. Identification of ions and gases
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6
Use The halogens are a group of elements showing trends in colour, state and reaction with other halide ions. Complete the word equation for the reaction of chlorine with aqueous potassium bromide. chlorine + potassium bromide → + Explain why an aqueous solution of iodine does not react with potassium chloride. The table shows the properties of some halogens. halogen state at room temperature colour boiling point / °C density of solid / g cm-3 fluorine gas yellow 1.51 chlorine green −35 1.56 bromine liquid red-brown iodine solid 4.93 Complete the missing spaces in the table. Suggest values for the boiling point of fluorine, the density of bromine. How many electrons does an atom of fluorine have in total, in its outer shell? State a use for chlorine.
8. The Periodic Table  →  8.3. Group VII properties
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7
Use Aluminium is extracted by the electrolysis of aluminium oxide dissolved in cryolite. B D C A A A + – positive electrode electrolyte (aluminium oxide dissolved in molten cryolite) molten aluminium steel case negative electrode What information in the diagram shows that aluminium is more dense than the electrolyte? What form of carbon is used for the electrodes in this electrolysis? Which letter in the diagram, A, B, C or D, represents the anode? Suggest why electrolysis is used to extract aluminium rather than reduction using carbon. Oxygen gas is released at the anode. Where does this oxygen come from? The oxygen reacts with the carbon anode to form carbon dioxide. What is the formula of carbon dioxide? Why does the anode decrease in size during electrolysis? Examiner's Use Each electrolysis cell makes 212 kg of aluminium per day from 400 kg of aluminium oxide. Calculate how much aluminium can be made from 1 tonne (1000 kg) of aluminium oxide. Complete the following sentences about the electrolysis of aluminium oxide using words from the following list. atoms gaseous molten solid ions molecules Aluminium oxide conducts electricity when it is because it contains which are free to move.
9. Metals  →  9.6. Extraction of metals
4. Electrochemistry  →  4.1. Electrolysis
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