9701_w12_qp_23 - revisedeck

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Carbon dioxide, CO2, makes up about 0.040 % of the Earth’s atmosphere. It is produced by animal respiration and by the combustion of fossil fuels. In animal respiration, oxygen reacts with a carbohydrate such as glucose to give water, carbon dioxide and energy. The typical daily food requirement of a human can be considered to be the equivalent of 1.20 kg of glucose, C6H12O6. You should express all of your numerical answers in this question to three signiﬁ cant ﬁ gures. Construct a balanced equation for the complete oxidation of glucose. Use your equation to calculate the amount, in moles, of CO2 produced by one person in one day from 1.20 kg of glucose. On the day on which this question was written, the World population was estimated to be 6.82 × 109. Calculate the total mass of CO2 produced by this number of people in one day. Give your answer in tonnes. [1 tonne = 1.00 ×106 g] For Examiner’s Use When fossil fuels are burned in order to give energy, carbon dioxide and water are also produced. The hydrocarbon octane, C8H18, can be used to represent the fuel burned in motor cars. A typical fuel-efﬁ cient motor car uses about 4.00 dm3 of fuel to travel 100 km. Construct a balanced equation for the complete combustion of octane. The density of octane is 0.700 g cm–3. Calculate the amount, in moles, of octane present in 4.00 dm3 of octane. Calculate the mass of CO2 produced when the fuel-efﬁ cient car is driven for a distance of 100 km. Calculate how many kilometres the same fuel-efﬁ cient car would have to travel in order to produce as much CO2 as is produced by the respiration of 6.82 × 109 people during one day. Use your answer to . Carbon dioxide is one of a number of gases that are responsible for global warming. When fossil fuels such as octane are burned in a car engine, other atmospheric pollutants are also produced. Give the formula of one atmospheric pollutant that may be produced in a car engine, other than CO2, and state how this pollutant damages the environment. pollutant damage caused

2. Atoms, molecules and stoichiometry → 2.4. Reacting masses and volumes (of solutions and gases)

14. Hydrocarbons → 14.1. Alkanes

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For Examiner’s Use Concentrated sulfuric acid may be used in a school or college laboratory to produce hydrogen chloride by reaction with solid chlorides such as sodium chloride. What will be seen when concentrated sulfuric acid is carefully added to solid sodium chloride? Write a balanced equation for this reaction. Solutions of both H2SO4 and HCl are strong acids. What is meant by the term strong acid ? If the same reaction is carried out with solid sodium iodide and concentrated sulfuric acid, hydrogen iodide is not produced. State one observation you would make when carrying out this reaction with solid sodium iodide. Explain why hydrogen iodide is not a product of this reaction. Aqueous silver nitrate and aqueous ammonia are used to test for the presence of halide ions. Aqueous silver nitrate is slowly added to aqueous sodium chloride and the resulting mixture is then shaken with an excess of aqueous ammonia. Describe what you would observe at each stage of this process. For Examiner’s Use Write balanced equations, with state symbols, for all reactions that occur in this process. The same process of adding aqueous silver nitrate followed by an excess of aqueous ammonia is repeated using aqueous sodium iodide instead of aqueous sodium chloride. State two differences that would be observed with aqueous sodium iodide.

11. Group 17 → 11.3. Some reactions of the halide ions

11. Group 17 → 11.4. The reactions of chlorine

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For Examiner’s Use Hydrogen is the most abundant element in the Universe, although on Earth only very small quantities of molecular hydrogen have been found to occur naturally. Hydrogen is manufactured on a large scale for use in the chemical industry and is also regarded as a possible fuel to replace fossil fuels in internal combustion engines. State one large scale use of hydrogen in the chemical industry. One common way of producing hydrogen on a large scale for use in the chemical industry is by the steam ‘reforming’ of methane (natural gas), in which steam and methane are passed over a catalyst at 1000–1400 K to produce carbon monoxide and hydrogen. CH4+ H2OCO+ 3H2∆H = +206 kJ mol–1 Use the information above to state and explain the effect on the equilibrium position of the following changes. increasing the pressure applied to the equilibrium decreasing the temperature of the equilibrium What will be the effect on the rate of the reaction of increasing the pressure at which it is carried out? Explain your answer. For Examiner’s Use Further hydrogen can be obtained by the ‘water-gas shift’ reaction in which the carbon monoxide produced is reacted with steam. CO+ H2OCO2+ H2Kc = 6.40 × 10–1 at 1100 K A mixture containing 0.40 mol of CO, 0.40 mol of H2O, 0.20 mol of CO2 and 0.20 mol of H2 was placed in a 1 dm3 ﬂ ask and allowed to come to equilibrium at 1100 K Give an expression for Kc for this reaction. Calculate the amount, in moles, of each substance present in the equilibrium mixture at 1100 K. CO+ H2OCO2+ H2initial moles 0.40 0.40 0.20 0.20

7. Equilibria → 7.1. Chemical equilibria: reversible reactions, dynamic equilibrium

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For Examiner’s Use Many organic compounds, including alcohols, carbonyl compounds, carboxylic acids and esters, contain oxygen. The table below lists some oxygen-containing organic compounds and some common laboratory reagents. Complete the table as fully as you can. If you think no reaction occurs, write ‘no reaction’ in the box for the structural formula. reaction organic compound reagent structural formulaof organic productA CH3CH(OH)CH3 NaBH4 B CH3COCH3 Tollens’ reagent warm C CH3CO2CH(CH3)2 KOHwarm D (CH3)3COH Cr2O7 2– / H+ heat under reﬂ ux E CH3COCH3 NaBH4 F (CH3)3COH PCl 5 G CH3CH CHCH2OH MnO4 – / H+ heat under reﬂ ux For Examiner’s Use During some of the reactions in a colour change occurs. Complete the table below for any such reactions, stating the letter of the reaction and what the colour change is. reaction colour at the beginning of the reaction colour at the end of the reaction

13. An introduction to AS Level organic chemistry → 13.1. Formulas, functional groups and the naming of organic compounds

13. An introduction to AS Level organic chemistry → 13.2. Characteristic organic reactions

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For Examiner’s Use The molecular formula C4H8O can represent a number of compounds which have different functional groups and which show different types of isomerism. Compounds H, J and K each have the molecular formula C4H8O. In each of the molecules of H, J and K, ● the carbon chain is unbranched and the molecule is not cyclic, ● no oxygen atom is attached to any carbon atom which is involved in π bonding. When compound H is reacted with sodium metal, a colourless ﬂ ammable gas is produced. Both J and K give an orange-red precipitate when reacted with 2,4-dinitrophenylhydrazine reagent but only K reacts with Fehling’s solution. Suggest possible structural formulae for H, J and K. Three structural formulae are possible for H but only one for J and one for K. H J K For Examiner’s Use In addition to being structural isomers of each other, some of the possible structures for H, J or K show cis-trans isomerism or are chiral. Draw the displayed formulae of those isomers which show cis-trans isomerism. Draw the displayed formulae of those isomers which are chiral, indicating in each case the chiral carbon atom with an asterisk (*).

13. An introduction to AS Level organic chemistry → 13.4. Isomerism: structural isomerism and stereoisomerism

13. An introduction to AS Level organic chemistry → 13.1. Formulas, functional groups and the naming of organic compounds

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