9701_s11_qp_21
A paper of Chemistry, 9701
Questions:
5
Year:
2011
Paper:
2
Variant:
1
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1
Examiner s Use Some intercontinental jet airliners use kerosene as fuel. The formula of kerosene may be taken as C14H30. To which homologous series of compounds does kerosene belong? When kerosene burns in an excess of air, carbon dioxide and water form. Balance the following equation for the complete combustion of kerosene. C14H30+ O2CO2+ H2O In this section, give your answers to one decimal place. The flight path from Beijing to Paris is approximately 8195 km. A typical intercontinental jet airliner burns 10.8 kg of kerosene for each kilometre covered. Calculate the mass, in tonnes, of C14H30 burnt on a flight from Beijing to Paris. [1 tonne = 1 000 kg] Use your equation in to calculate the mass, in tonnes, of CO2 produced during this flight. For Examiner’s Use Bicycles may be carried on commercial airliners. When carried on airliners, bicycles are placed in the luggage hold. This is a part of the aircraft which, in flight, will have different temperatures and air pressures from those at sea level. This question concerns the change in pressure in an inflated bicycle tyre from when it is at sea level to when it is in the hold of an airliner in flight. At sea level and a temperature of 20 °C an inflated bicycle tyre contains 710 cm3 of air at an internal pressure of 6 × 105 Pa. Use the general gas equation PV = nRT to calculate the amount, in moles, of air in the tyre at sea level. The same bicycle, with its tyres inflated at sea level as described in above, is placed in the luggage hold of an airliner. At a height of 10 000 m, the temperature in the luggage hold is 5 °C and the air pressure is 2.8 × 104 Pa. Assuming the volume of the tyre does not change, use your answer to to calculate the pressure inside the tyre at a height of 10 000 m.
2. Atoms, molecules and stoichiometry  →  2.4. Reacting masses and volumes (of solutions and gases)
4. States of matter  →  4.1. The gaseous state: ideal and real gases and \( pV = nRT \)
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For Examiner’s Use Crude oil contains a mixture of hydrocarbons together with other organic compounds which may contain nitrogen, oxygen or sulfur in their molecules. At an oil refinery, after the fractional distillation of crude oil, a number of other processes may be used including ‘cracking’, ‘isomerisation’, and ‘reforming’. What is meant by the term ‘cracking ’ and why is it carried out? Outline briefly how the cracking of hydrocarbons would be carried out. Construct a balanced equation for the formation of heptane, C7H16, by cracking tetradecane, C14H30. One of the sulfur-containing compounds present in crude oil is ethanethiol, C2H5SH, the sulfur-containing equivalent of ethanol. Ethanethiol is toxic and is regarded as one of the smelliest compounds in existence. The boiling point of ethanol, C2H5OH, is higher than that of C2H5SH. Suggest a reason for this difference. For Examiner’s Use When ethanethiol is burned in an excess of air, three oxides of different elements are formed. Construct a balanced equation for this reaction. Two of the oxides formed cause serious environmental damage. For each of these oxides, identify the type of pollution caused and describe one consequence of this pollution. A small amount of ethanethiol is added to liquefied gases such as butane that are widely used in portable cooking stoves. Suggest a reason for this. Sulfur-containing compounds are removed from oil products at the refinery. The sulfur is recovered and converted into SO2, which is then used in the Contact process. State the main operating details of the formation of SO3 in the Contact process.
14. Hydrocarbons  →  14.1. Alkanes
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For Examiner’s Use Calcium is the fifth most common element in the Earth’s crust. Calcium compounds occur in bones and teeth and also in many minerals. Some reactions of calcium and its compounds are shown in the reaction scheme below. UCadilute HCl H2OH2OWreaction 1 XVroast in air dilute HNO3 dilute H2SO4 ZNa2CO3YState the formula of each of the calcium compounds U to Y. U V W X Y Compound Y may be converted into compound V. Outline how this reaction would be carried out in a school or college laboratory using a small sample of Y. For Examiner’s Use Construct balanced equations for the following reactions. calcium to compound U compound V to compound W compound U to compound Y Construct a balanced equation for the effect of heat on solid compound W. Suggest the formula of an aqueous reagent, other than an acid, for reaction 1. What would be observed when each of the following reactions is carried out in a test- tube? the formation of X from Cathe formation of X from V
11. Group 17  →  11.4. The reactions of chlorine
9. The Periodic Table: chemical periodicity  →  9.2. Periodicity of chemical properties of the elements in Period 3
10. Group 2  →  10.1. Similarities and trends in the properties of the Group 2 metals, magnesium to barium, and their compounds
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For Examiner’s Use Ketones are widely used as solvents and as intermediates in the chemical industry. Ketones contain the reactive keto group, C O. Propanone, CH3COCH3, undergoes a reaction with hydrogen cyanide, HCN. What type of reaction is this? What reagents are used? Draw a diagram to show the dipole present in the propanone molecule. For Examiner’s Use Propanone reacts with 2,4-dinitrophenylhydrazine reagent. H2N NO2 NO2 N H 2,4-dinitrophenylhydrazine Construct a balanced equation for the reaction between propanone and 2,4-dinitrophenylhydrazine. A similar type of reaction occurs between propanone and hydroxylamine, NH2OH. Draw the displayed formula of the organic product of this reaction. H3C H3C C O + H H N OH
17. Carbonyl compounds  →  17.1. Aldehydes and ketones
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For Examiner’s Use The gas ethyne, C2H2, more commonly known as acetylene, is manufactured for use in the synthesis of organic compounds. It is also used, in combination with oxygen, in ‘oxy-acetylene’ torches for the cutting and welding of metals. Industrially, ethyne is made from calcium carbide, CaC2, or by cracking liquid hydrocarbons. When calcium carbide is reacted with water, ethyne and calcium hydroxide are formed. Construct a balanced equation for this reaction. Ethyne can also be obtained from ethene by using the following sequence of reactions. CH2CH2 HCCH ClCH2CH2Cl step 1 step 2 What types of reaction are step 1 and step 2? step 1 step 2 Suggest what reagent and conditions would be used in a laboratory in step 2. reagent conditions When ethyne is passed into water at 60 °C, in the presence of a little H2SO4 and Hg2+ ions, a pungent, colourless organic liquid, Q, with Mr of 44 is obtained. This is step 3. When Q is warmed with Tollens’ reagent in a test-tube, a silver mirror is formed. On acidification, the solution remaining in the test-tube is found to contain the organic compound R which has Mr of 60. This is step 4. Give the structural formulae of Q and R. HCCH step 3 Q step 4 R What type of reaction is step 3 and step 4? step 3 step 4 For Examiner’s Use The standard enthalpy change of combustion of C2H2, ΔH o–– c, is –1300 kJ mol–1 at 298 K. Values of relevant standard enthalpy changes of formation, ΔH o–– f, measured at 298 K, are given in the table. substance ΔH o–– f / kJ mol–1 CO2–394 H2O–286 Write balanced equations, with state symbols, that represent the standard enthalpy change of combustion, ΔH o–– c, of C2H2, and the standard enthalpy change of formation, ΔH o–– f, of C2H2. Use the data above and your answer to to calculate the standard enthalpy change of formation, ΔH o–– f, of C2H2. Show clearly whether the standard enthalpy change of formation of C2H2 has a positive or negative value.
14. Hydrocarbons  →  14.1. Alkanes
2. Atoms, molecules and stoichiometry  →  2.4. Reacting masses and volumes (of solutions and gases)
14. Hydrocarbons  →  14.2. Alkenes
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