0620_s16_qp_33
A paper of Chemistry, 0620
Questions:
8
Year:
2016
Paper:
3
Variant:
3
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1
The structures of some substances containing carbon are shown. C C H H H H Ca2+ C2 2– C2 2– C2 2– C2 2– C2 2– C2 2– Ca2+ Ca2+ Ca2+ Ca2+ Ca2+ C C C C C C C C C C C C C CC C C C C C C C C C C C C C C C C C C C C CC C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C A B D E C C C C C H H H H H Cl Cl Cl Cl Cl C Answer the following questions about these substances. Which two substances have giant covalent structures? and Which substance decolourises aqueous bromine? Which substance is most likely to be a gas at room temperature and pressure? Which substance is a hydrocarbon? Determine the simplest formula for substance D. 1 10 Two isotopes of carbon are C and C. How do these two isotopes differ in their atomic structure? Determine the number of neutrons present in one atom of the isotope C. [Turn over 1 10
2. Atoms, elements and compounds  →  2.3. Isotopes
2. Atoms, elements and compounds  →  2.6. Giant covalent structures
3. Stoichiometry  →  3.2. Relative masses of atoms and molecules
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2
This question is about metals. The table shows some properties of the metals, R, S, T and U. melting point /°C density in g/cm3 relative heat conductivity relative electrical conductivity metal 2.7 11.8 4.3 R 7.9 4.2 1.2 S 8.9 22.3 6.2 T 7.1 12.4 4.1 U Which metal would be best to make the base of a pan for cooking food? Use the information in the table to explain your answer. Zinc chloride can be made by reacting excess zinc with hydrochloric acid. Suggest how the excess zinc can be removed from the reaction mixture. Zinc can be obtained from molten zinc chloride by electrolysis. What is meant by the term electrolysis? 1 10 Draw a labelled diagram of the apparatus that could be used to electrolyse molten zinc chloride. Give one advantage of recycling metals. [Turn over 1 10
9. Metals  →  9.2. Uses of metals
9. Metals  →  9.1. Properties of metals
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3
The table gives some information about the halogens. boiling point/°C melting point/°C colour element –35 –101 light green chlorine +59 –7 red-brown bromine +184 +114 grey-black iodine +337 +302 astatine Predict the colour of astatine. Describe the trend in the boiling points of the halogens. Deduce the state of chlorine at –50°C. Explain your answer. Complete the word equation for the reaction of bromine with aqueous potassium astatide. bromine + potassium astatide → + Suggest why bromine does not react with aqueous potassium chloride. 1 10 Compound X is used to prepare the dye methyl orange. The structure of compound X is shown. C C C C C N+ NCl – C S O O H H H H O H Complete the table and calculate the relative molecular mass of compound X. atomic mass number of atoms type of atom 6 × 12 = 72 carbon 5 × 1 = 5 hydrogen 2 × 14 = 28 nitrogen 1 × 32 = 32 sulfur oxygen chlorine relative molecular mass = Describe how you could use methyl orange to distinguish between solutions of hydrochloric acid and sodium hydroxide. [Turn over 1 10 Methyl orange and Congo red are dyes. A mixture of methyl orange and Congo red can be separated by chromatography. Draw a labelled diagram to show how the apparatus is arranged to carry out chromatography. 1 10
8. The Periodic Table  →  8.3. Group VII properties
11. Organic chemistry  →  11.4. Alkanes
11. Organic chemistry  →  11.5. Alkenes
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4
Petroleum is a mixture of hydrocarbons. What is the meaning of the term hydrocarbon? Petroleum can be separated into different fractions by fractional distillation. The diagram shows a fractionating column. The fractions are shown by letters. petroleum A B C D E F furnace Describe how fractional distillation is used to separate the petroleum into fractions. In your answer refer to • changes of state, • differences in boiling points. 1 10 The properties of the fractions are shown in the table. boiling range / °C percentage by mass of the fraction number of carbon atoms fraction less than 40 1 – 4 A 40 – 160 4 – 10 B 160 – 250 10 – 16 C 250 – 300 16 – 20 D 300 – 350 20 – 25 E more than 350 more than 25 F total = 100 Describe how the number of carbon atoms affects the boiling range. Determine the percentage by mass of fraction F in this sample of petroleum. Which one of the fractions is mainly gaseous at 25°C? Fraction F is the residue. It contains bitumen. Give one use of bitumen. Fraction C can be cracked to form alkenes. Describe one condition required for cracking. [Turn over 1 10 Complete the chemical equation for the cracking of dodecane, C12H26, to form heptane, C7H16, and one other hydrocarbon. C12H26 →C7H16 +
11. Organic chemistry  →  11.3. Fuels
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5
Iron is a transition element. Describe the physical and chemical properties of iron. Iron carbonyl, Fe(CO)5, is a covalent liquid. Suggest two physical properties of iron carbonyl. When heated above 200°C, iron carbonyl undergoes thermal decomposition. Fe(CO)5(→Fe+ 5COExplain why this reaction could have an adverse effect on health if not carried out in a fume cupboard. 1 10
9. Metals  →  9.1. Properties of metals
8. The Periodic Table  →  8.4. Transition elements
6. Chemical reactions  →  6.1. Physical and chemical changes
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6
Ethanol can be manufactured by reacting ethene with steam. C2H4+ H2O⇌C2H5OHWhat is the meaning of the symbol ⇌? State two conditions needed for this reaction. The energy level diagram for this reaction is shown. energy C2H4+ H2OC2H5OHIs this reaction exothermic or endothermic? Give a reason for your answer. [Turn over 1 10 The graph below shows how the percentage yield of ethanol changes with temperature when the pressure is kept constant. temperature / °C % yield of ethanol Describe how the percentage yield changes with temperature. Determine the percentage yield when the temperature is 350°C. Complete the structure of ethanol, C2H5OH, to show all atoms and all bonds. H H C H Give one use of ethanol. 1 10 Complete the chemical equation for the complete combustion of ethanol. C2H5OH + 3O2 → CO2 + H2O [Turn over 1 10
11. Organic chemistry  →  11.6. Alcohols
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7
A student investigated the reaction between zinc and sulfuric acid at 20°C using the apparatus shown. The zinc was in excess. zinc gas syringe sulfuric acid What should the student do to start the reaction? The graph shows the volume of hydrogen released as the reaction proceeds. time / minutes volume of hydrogen / cm3 1 10 Explain why the volume of gas stays the same after 10 minutes. How long did it take for the first 20cm3 of gas to be collected? The student repeated the experiment at 30°C. All other conditions remained the same. Draw the shape of the line on the grid on page 16 when the reaction was carried out at 30°C. The student repeated the experiment using zinc powder instead of small pieces of zinc. Describe and explain how the rate of reaction differs when zinc powder is used. Sulfuric acid is a compound. What is the meaning of the term compound? Sulfur is used to make sulfuric acid. Give one source of sulfur. Sulfur is oxidised by air to form sulfur dioxide. Give one use of sulfur dioxide. [Turn over 1 10
6. Chemical reactions  →  6.2. Rate of reaction
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8
The graph shows how increasing the pressure at constant temperature changes the volume of a fixed mass of carbon dioxide gas. volume pressure Describe how the volume of gas changes with pressure. What happens to the average distance of the molecules from each other when the pressure is decreased? Carbon dioxide can be reduced by magnesium. 2Mg+ CO2→2MgO+ CUse the information in the equation to show that carbon dioxide gets reduced. Which one of these processes does not produce carbon dioxide? Tick one box. respiration reaction of an acid with a metal oxide reaction of an acid with a carbonate thermal decomposition of limestone 1 10 Give two problems caused by increasing the amount of carbon dioxide in the atmosphere. [Turn over 1 10
1. States of matter  →  1.1. Solids, liquids and gases
10. Chemistry of the environment  →  10.3. Air quality and climate
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