Alkanes — Paper 1 · A Level Chemistry 9701

24 Light initiates the following reaction. alkane + chlorine → chloroalkane + hydrogen chloride What happens to chlorine in this photochemical reaction? A heterolytic fission to give an electrophile B homolytic fission to give an electrophile C heterolytic fission to give a free radical D homolytic fission to give a free radical

1 marks

Answer: D

This question in 9701/11 May/June 2006

25 High-energy irradiation in the stratosphere produces radicals from chlorofluoroalkanes, commonly known as CFCs. Which radical could result from this irradiation of CHFClCF2Cl? A CHFClCFCl B CHClCF2Cl C CHFCF2Cl D CFClCF2Cl

1 marks

Answer: C

This question in 9701/11 May/June 2006

4 Samples of 10 cm3 of each of the first four members of the alkane series are separately mixed with 70 cm3 of oxygen. Each is then burned and the total volume, V, of residual gas measured again at room temperature and pressure. Which graph represents the results that would be obtained? A B V / cm3 V / cm3 X 80 80 X 60 60 X 40 X 40 X X 20 X 20 X 0 0 CH4 C3H8 CH4 C3H8 C2H6 C4H10 C2H6 C4H10 C D V / cm3 V / cm3 80 80 60 60 X X X X X 40 X 40 X 20 X 20 0 0 CH4 C3H8 CH4 C3H8 C2H6 C4H10 C2H6 C4H10

1 marks

Answer: D

This question in 9701/11 Oct/Nov 2006

24 When gaseous chemicals are transported by road or by rail they are classified as follows. flammable non-flammable poisonous Which gas is non-flammable? A butane B hydrogen C oxygen D propene

1 marks

Answer: C

This question in 9701/11 Oct/Nov 2006

21 Tetramethyl-lead(IV), (CH3)4Pb, increases the rate of the reaction of methane with chlorine. CH4(g) + Cl2(g) → CH3Cl(g) + HCl(g) Why can tetramethyl-lead(IV) behave in this way? A It is a source of methyl radicals. B It releases CH3 + (g) . C It reacts with chloromethane and prevents equilibrium being established. D Metal ions catalyse the reaction.

1 marks

Answer: A

This question in 9701/11 Oct/Nov 2007

22 Which reaction occurs when ethane and chlorine are mixed in diffused sunlight? A a free-radical substitution with hydrogen given off B a free-radical substitution with hydrogen chloride given off C a free-radical substitution with no gas given off D a nucleophilic substitution with hydrogen chloride given off

1 marks

Answer: B

This question in 9701/11 Oct/Nov 2007

23 Which hydrocarbon would not be collected in the inverted tube by heating pentane, CH3(CH2)3CH3, in the apparatus shown? pentane on aluminium mineral fibre oxide hydrocarbons very strong heat water A CH4 B CH3CH3 C CH3CH2CH=CH2 D CH3(CH2)8CH3

1 marks

Answer: D

This question in 9701/11 May/June 2008

39 During the bromination of methane, the free radical CH is generated and a possible terminating • 3 step of this reaction is the formation of C2H6 by the combination of two free radicals. What could be produced in a terminating step during the bromination of propane? CH3 1 CH3CH2CH2CHCH3 CH3 CH3 2 CH3CHCHCH3 CH3 3 CH3CH2CHCH2CH3

1 marks

Answer: B

This question in 9701/11 Oct/Nov 2008

22 Trichloroethanoic acid, CCl3CO2H, is used in cosmetic surgery to perform a ‘chemical peel’ to remove dead skin. Trichloroethanoic acid can be made by reacting chlorine with ethanoic acid. What is the mechanism of this reaction? A electrophilic addition B electrophilic substitution C free radical addition D free radical substitution

1 marks

Answer: D

This question in 9701/11 May/June 2009

37 A fraction of distilled crude oil contains molecules with between 15 and 19 carbon atoms. This fraction is cracked by strong heating. Why is this done? 1 To produce alkenes. 2 To produce smaller molecules which are in higher demand. 3 To insert oxygen atoms into the hydrocarbons.

1 marks

Answer: B

This question in 9701/11 May/June 2009

22 What is the least number of carbon atoms in a non-cyclic alkane molecule that has a chiral centre? A 7 B 8 C 9 D 10

1 marks

Answer: A

This question in 9701/11 Oct/Nov 2009

26 Which equation represents a valid propagation step in the free radical reaction between ethane and chlorine? A C2H6 + Cl • → C2H5Cl + H• B C2H5Cl + Cl • → C2H4Cl • + HCl C C2H6 + H• → C 2H • + HCl 5 D C2H5 • + Cl • → C2H5Cl

1 marks

Answer: B

This question in 9701/11 Oct/Nov 2009

39 The diagram shows an experiment. silica, alumina or baked clay liquid X on mineral wool gas collected support strong gentle heat trough of heat water Which processes could be demonstrated by using the above apparatus? 1 the oxidation of ethanol (the liquid X) 2 the dehydration of ethanol (the liquid X) 3 the cracking of paraffin (the liquid X)

1 marks

Answer: C

This question in 9701/11 Oct/Nov 2009

20 When gaseous chemicals are transported by road or by rail they are classified as follows. flammable non-flammable poisonous Which commonly transported gas is non-flammable? A butane B hydrogen C oxygen D propene

1 marks

Answer: C

This question in 9701/11 May/June 2010

21 When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical substitution. In a propagation step the free radical X• is formed. CH3 CH3CH2 C CH3 + Cl → X + HCl ● ● CH3 How many different forms of X• are possible? A 1 B 2 C 3 D 4

1 marks

Answer: C

This question in 9701/11 May/June 2010

38 Which structural formulae represent 2,2-dimethylpentane? 1 (CH3)2CHCH2CH(CH3)2 2 (CH3)3CCH2CH2CH3 3 CH3CH2CH2C(CH3)3

1 marks

Answer: C

This question in 9701/11 May/June 2010

20 When gaseous chemicals are transported by road or by rail they are classified as follows. flammable non-flammable poisonous Which commonly transported gas is non-flammable? A butane B hydrogen C oxygen D propene

1 marks

Answer: C

This question in 9701/12 May/June 2010

25 When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical substitution. In a propagation step the free radical X• is formed. CH3 CH3CH2 C CH3 + Cl → X + HCl ● ● CH3 How many different forms of X• are possible? A 1 B 2 C 3 D 4

1 marks

Answer: C

This question in 9701/12 May/June 2010

39 Which structural formulae represent 2,2-dimethylpentane? 1 (CH3)2CHCH2CH(CH3)2 2 (CH3)3CCH2CH2CH3 3 CH3CH2CH2C(CH3)3

1 marks

Answer: C

This question in 9701/12 May/June 2010

20 When gaseous chemicals are transported by road or by rail they are classified as follows. flammable non-flammable poisonous Which commonly transported gas is non-flammable? A butane B hydrogen C oxygen D propene

1 marks

Answer: C

This question in 9701/13 May/June 2010

23 When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical substitution. In a propagation step the free radical X• is formed. CH3 CH3CH2 C CH3 + Cl → X + HCl ● ● CH3 How many different forms of X• are possible? A 1 B 2 C 3 D 4

1 marks

Answer: C

This question in 9701/13 May/June 2010

37 Which structural formulae represent 2,2-dimethylpentane? 1 (CH3)2CHCH2CH(CH3)2 2 (CH3)3CCH2CH2CH3 3 CH3CH2CH2C(CH3)3

1 marks

Answer: C

This question in 9701/13 May/June 2010

23 The products obtained by cracking an alkane, X, are methane, ethene and propene. The mole fraction of ethene in the products is 0.5. What is the identity of X? A C6H14 B C8H18 C C9H20 D C11H24

1 marks

Answer: B

This question in 9701/12 May/June 2011

22 In the reaction pathway below, an alkane is converted into a carboxylic acid through several stages. stage 1 stage 2 stage 3 C10H22 C2H4 C2H5OH CH3CO2H catalytic hydration Which processes occur at stage 1 and at stage 3? stage 1 stage 3 A condensation combustion B cracking dehydration C cracking oxidation D dehydration combustion

1 marks

Answer: C

This question in 9701/13 May/June 2011

22 In the general formula of which class of compound, is the ratio of hydrogen atoms to carbon atoms the highest? A alcohols B aldehydes C carboxylic acids D halogenoalkanes

1 marks

Answer: A

This question in 9701/11 Oct/Nov 2011

27 A reaction between chlorine and propane in ultraviolet light produces two isomeric monochloropropanes, C3H7Cl, as products. Which information about this reaction is correct? expected ratio of type of bond fission 1-chloropropane to in initiation step 2-chloropropane produced A heterolytic 1 : 1 B heterolytic 3 : 1 C homolytic 1 : 1 D homolytic 3 : 1

1 marks

Answer: D

This question in 9701/11 Oct/Nov 2011

13 Methyl mercaptan, CH3SH, has a foul smell and is often used to impart a smell to natural gas. What will be formed when CH3SH is burned in an excess of air? A CO H2O SO2 B CO2 H2O H2S C CO2 H2O SO2 D CO2 H2O SO3

1 marks

This question in 9701/12 Oct/Nov 2011

23 In the general formula of which class of compound, is the ratio of hydrogen atoms to carbon atoms the highest? A alcohols B aldehydes C carboxylic acids D halogenoalkanes

1 marks

Answer: A

This question in 9701/13 Oct/Nov 2011

28 A reaction between chlorine and propane in ultraviolet light produces two isomeric monochloropropanes, C3H7Cl, as products. Which information about this reaction is correct? expected ratio of type of bond fission 1-chloropropane to in initiation step 2-chloropropane produced A heterolytic 1 : 1 B heterolytic 3 : 1 C homolytic 1 : 1 D homolytic 3 : 1

1 marks

Answer: D

This question in 9701/13 Oct/Nov 2011

19 Which substance does not produce a poisonous gas, when burnt in a limited amount of air? A hydrogen B methane C propene D sulfur

1 marks

Answer: A

This question in 9701/12 May/June 2012

24 Oct-1-ene, CH3(CH2)5CH=CH2, is subjected to thermal cracking. Which combination of compounds W, X, Y and Z can be obtained? CH2=CH2 CH3CH=CH2 CH3CH2CH3 CH2=CHCH=CH2 W X Y Z A W, X, Y and Z B W, X and Y only C W, X and Z only D W and X only

1 marks

Answer: A

This question in 9701/12 May/June 2012

39 Which statements about the photochemical chlorination of ethane are correct? 1 Hydrogen gas is one of the products. 2 A propagation step in the mechanism is C2H6 + Cl • → C2H5• + HCl. 3 The initiation step is the homolytic fission of chlorine.

1 marks

Answer: C

This question in 9701/12 May/June 2012

23 The cracking of a single hydrocarbon molecule, CnH2n+2, produces two hydrocarbon molecules only. Each hydrocarbon product contains the same number of carbon atoms in one molecule. Each hydrocarbon product has non-cyclic structural isomers. What is the value of n? A 4 B 6 C 8 D 9

1 marks

Answer: C

This question in 9701/11 Oct/Nov 2012

25 One of the reactions taking place in a catalytic converter in a car exhaust system is between nitrogen oxide and octane (unburned petrol). The products of this reaction are non-toxic. Which is the correct equation for the reaction? A C8H16 + 16NO → 8CO + 8N2 + 8H2O B C8H16 + 24NO → 8CO2 + 12N2 + 8H2O C C8H18 + 17NO → 8CO + 8 2 1 N2 + 9H2O D C8H18 + 25NO → 8CO2 + 12 2 1 N2 + 9H2O

1 marks

Answer: D

This question in 9701/11 Oct/Nov 2012

37 Which reagents and conditions will convert propane into 1-chloropropane? 1 Cl 2 and sunlight 2 conc. HCl, reflux 3 PCl 5

1 marks

Answer: D

This question in 9701/11 Oct/Nov 2012

23 The cracking of a single hydrocarbon molecule, CnH2n+2, produces two hydrocarbon molecules only. Each hydrocarbon product contains the same number of carbon atoms in one molecule. Each hydrocarbon product has non-cyclic structural isomers. What is the value of n? A 4 B 6 C 8 D 9

1 marks

Answer: C

This question in 9701/12 Oct/Nov 2012

25 One of the reactions taking place in a catalytic converter in a car exhaust system is between nitrogen oxide and octane (unburned petrol). The products of this reaction are non-toxic. Which is the correct equation for the reaction? A C8H16 + 16NO → 8CO + 8N2 + 8H2O B C8H16 + 24NO → 8CO2 + 12N2 + 8H2O C C8H18 + 17NO → 8CO + 8 2 1 N2 + 9H2O D C8H18 + 25NO → 8CO2 + 12 2 1 N2 + 9H2O

1 marks

Answer: D

This question in 9701/12 Oct/Nov 2012

25 Pentane, C5H12, is reacted with chlorine in the presence of ultraviolet light. A compound R is found in the products. R has molecular formula C5H10Cl 2. Each molecule of R contains one chiral carbon atom. Which two atoms of the pentane chain could be bonded to chlorine atoms in this isomer? A 1 and 3 B 1 and 5 C 2 and 3 D 2 and 4

1 marks

Answer: A

This question in 9701/11 May/June 2013

31 Use of the Data Booklet is relevant to this question. Free-radicals play an important part in reactions involving the destruction of the ozone layer and the substitution of alkanes by chlorine. Some free-radicals contain two unpaired electrons. Such species are called diradicals. Which species are diradicals? 1 O 2 Cl 3 CH3

1 marks

Answer: D

This question in 9701/11 May/June 2013

37 Which molecules would be present in the mixture produced by the photochemical chlorination of methane? 1 hydrogen 2 hydrogen chloride 3 dichloromethane

1 marks

Answer: C

This question in 9701/11 May/June 2013

22 When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical substitution. In a propagation step a free radical X• is formed. CH3 CH3CH2 C CH3 + Cl • → X• + HCl CH3 How many different forms of X• are possible? A 1 B 2 C 3 D 4

1 marks

Answer: C

This question in 9701/12 May/June 2013

37 During the bromination of methane, the free radical CH3• is generated. A possible terminating step of this reaction is the formation of C2H6 by the combination of two free radicals. What could be produced in a terminating step during the bromination of propane? CH3 1 CH3CH2CH2CHCH3 CH3 2 CH3CHCHCH3 CH3 CH3 3 CH3CH2CHCH2CH3

1 marks

Answer: B

This question in 9701/13 May/June 2013

7 Which stage in the free radical substitution of methane by chlorine will have the lowest activation energy? A CH3• + Cl 2 → CH3Cl + Cl • B Cl • + Cl • → Cl 2 C Cl • + CH4 → CH3• + HCl D Cl 2 → Cl • + Cl •

1 marks

Answer: B

This question in 9701/11 Oct/Nov 2013

7 Which stage in the free radical substitution of methane by chlorine will have the lowest activation energy? A CH3• + Cl 2 → CH3Cl + Cl • B Cl • + Cl • → Cl 2 C Cl • + CH4 → CH3• + HCl D Cl 2 → Cl • + Cl •

1 marks

Answer: B

This question in 9701/12 Oct/Nov 2013

6 Which stage in the free radical substitution of ethane by chlorine will have the lowest activation energy? A Cl 2 → 2Cl ● B Cl ● + C2H6 → C2H5● + HCl C C2H5● + Cl 2 → C2H5Cl + Cl ● D Cl ● + C2H5● → C2H5Cl

1 marks

Answer: D

This question in 9701/13 Oct/Nov 2013

24 There are three structural isomers with the formula C5H12. Which formulae correctly represent these three structural isomers? A CH3CH2CH2CH2CH3 CH3CH2CHCH3CH3 CH3CH3CCH3CH3 B CH3CH2CH2CH2CH3 CH3CH2(CH)CH3CH3 C(CH3)4 C CH3CH2CH2CH2CH3 CH3CH(CH3)CH2CH3 CH3C(CH3)2CH3 D CH3CH2CH2CH2CH3 CH3CH(CH3)CH2CH3 CH3CH2CH(CH3)CH3

1 marks

Answer: C

This question in 9701/11 May/June 2014

27 The hydrocarbon C17H36 can be cracked. Which compound is the least likely to be produced in this reaction? A C3H8 B C4H8 C C8H16 D C16H34

1 marks

Answer: D

This question in 9701/11 May/June 2014

21 In the presence of ultraviolet light, ethane and chlorine react to give a mixture of products. Which compound could be present in the mixture of products? A CH3Cl B CH3CH2CH2Cl C CH3CH2CH2CH3 D CH3CH2CH2CH2CH3

1 marks

Answer: C

This question in 9701/13 May/June 2014

23 Which molecule could not be obtained from the cracking of a molecule of nonane, CH3(CH2)7CH3? A CH2=CHCH=CH2 B CH3CH2CH2CH2CH3 C CH3CH2CH2CH2CH2CH=CH2 D (CH3CH2CH2)3CH

1 marks

Answer: D

This question in 9701/13 May/June 2014

24 A student investigates four different fuels. Each fuel is used separately to raise the temperature of 1 dm3 of water from 20 °C to 100 °C. Each fuel undergoes complete combustion. All other conditions are the same in each experiment. Which fuel would produce the smallest amount of carbon dioxide in these experiments? energy released fuel per mole of fuel A ethanol 1367 kJ mol–1 B methane 890 kJ mol–1 C methanol 715 kJ mol–1 D propane 2220 kJ mol–1

1 marks

Answer: B

This question in 9701/13 May/June 2014

30 The free radical substitution reaction between methane and chlorine involves initiation, propagation and termination stages. Which row is correct? involved in radical produced in initiation stage a propagation stage A heterolytic fission H• B heterolytic fission CH3• C homolytic fission H• D homolytic fission CH3•

1 marks

Answer: D

This question in 9701/13 May/June 2014

40 The diagram shows an experimental set-up which can be used in several different experiments. silica, alumina or baked clay liquid X on mineral wool gas collected support strong gentle heat trough of heat water Which processes could be demonstrated by using the above apparatus? 1 oxidation of ethanol (liquid X) 2 dehydration of ethanol (liquid X) 3 cracking of paraffin (liquid X)

1 marks

Answer: C

This question in 9701/13 May/June 2014

6 Aluminium carbide, Al 4C3, reacts readily with aqueous sodium hydroxide. The two products of the reaction are NaAl O2 and a hydrocarbon. Water molecules are also involved as reactants. What is the formula of the hydrocarbon? A CH4 B C2H6 C C3H8 D C6H12

1 marks

Answer: A

This question in 9701/11 Oct/Nov 2014

29 Which equation correctly represents the balanced equation for the complete combustion of a hydrocarbon with the formula CxHy? A y )O2 → xCO2 + 2 y H2O CxHy + (x + 2 B y )O2 → xCO2 + yH2O CxHy + (x + 4 C y )O2 → xCO2 + 4 y H2O CxHy + (x + 4 D y )O2 → xCO2 + 2 y H2O CxHy + (x + 4

1 marks

Answer: D

This question in 9701/11 Oct/Nov 2014

29 Which equation correctly represents the balanced equation for the complete combustion of a hydrocarbon with the formula CxHy? A y )O2 → xCO2 + 2 y H2O CxHy + (x + 2 B y )O2 → xCO2 + yH2O CxHy + (x + 4 C y )O2 → xCO2 + 4 y H2O CxHy + (x + 4 D y )O2 → xCO2 + 2 y H2O CxHy + (x + 4

1 marks

Answer: D

This question in 9701/12 Oct/Nov 2014

37 Which statements about the photochemical chlorination of ethane are correct? 1 A propagation step in the mechanism is C2H5• + Cl 2 → C2H5Cl + Cl •. 2 Butane is present in the products. 3 The initiation step is the heterolytic fission of chlorine.

1 marks

Answer: B

This question in 9701/13 Oct/Nov 2014

22 Four students, W, X, Y and Z, made the following statements about alkanes and alkenes. W ‘Bromine reacts with alkanes by electrophilic substitution.’ X ‘Bromine reacts with alkenes by a free-radical addition mechanism.’ Y ‘Alkenes can be oxidised by acidified manganate(VII) ions.’ Z ‘Alkenes are formed from alkanes by cracking.’ Which two students are correct? A W and X B W and Z C X and Y D Y and Z

1 marks

Answer: D

This question in 9701/12 May/June 2015

23 The first propagation step in the reaction between methane and chlorine is shown. CH4 + Cl • → CH3• + HCl How many different first propagation steps are possible in the reaction between pentane and chlorine? A 2 B 3 C 4 D 5

1 marks

Answer: B

This question in 9701/11 May/June 2016

11 Which stage in the free radical substitution of ethane by chlorine has the lowest activation energy? A Cl 2 → 2Cl ● B Cl ● + C2H6 → C2H5● + HCl C C2H5● + Cl 2 → C2H5Cl + Cl ● D Cl ● + C2H5● → C2H5Cl

1 marks

Answer: D

This question in 9701/12 May/June 2016

20 Chlorofluorocarbons damage the ozone layer by undergoing reactions with a free radical mechanism. The first stage of this is initiation. Which equation is most likely to be the initiation stage when chlorofluoromethane is involved in such a reaction? A B H H H H F C H C H + F F C H F C H + Cl Cl Cl Cl C D H H H F C H F C H + H F C H C H + Cl + F Cl Cl Cl

1 marks

Answer: B

This question in 9701/12 May/June 2016

23 When heated with chlorine, the hydrocarbon 2,2-dimethylbutane undergoes free radical substitution. In a propagation step a free radical X• is formed. CH3 CH3CH2 C CH3 + Cl • → X• + HCl CH3 How many different structures of X• are possible? A 2 B 3 C 4 D 5

1 marks

Answer: B

This question in 9701/13 May/June 2016

36 Catalytic converters are used to modify exhaust emissions from motor vehicles. Which reactions occur in catalytic converters? 1 C8H18 + 12 2 1 O2 → 8CO2 + 9H2O 2 2NO + 2CO → N2 + 2CO2 3 NO + SO3 → NO2 + SO2

1 marks

Answer: B

This question in 9701/11 Oct/Nov 2016

36 Catalytic converters are used to modify exhaust emissions from motor vehicles. Which reactions occur in catalytic converters? 1 C8H18 + 12 2 1 O2 → 8CO2 + 9H2O 2 2NO + 2CO → N2 + 2CO2 3 NO + SO3 → NO2 + SO2

1 marks

Answer: B

This question in 9701/13 Oct/Nov 2016

22 Which equation represents the initiation step of the substitution reaction between methane and chlorine? A CH4 → CH3• + H• B CH4 → CH3 – + H+ C Cl 2 → 2Cl • D Cl 2 → Cl + + Cl –

1 marks

Answer: C

This question in 9701/12 May/June 2017

2 A 0.216 g sample of an aluminium compound X reacts with an excess of water to produce a single hydrocarbon gas. This gas burns completely in O2 to form H2O and CO2 only. The volume of CO2 at room temperature and pressure is 108 cm3. What is the formula of X? A Al 2C3 B Al 3C2 C Al 3C4 D Al 4C3

1 marks

Answer: D

This question in 9701/13 May/June 2017

37 Which mechanisms are represented in this sequence of reactions? CH3CH2CH3 → CH3CH2CH2Cl → CH3CH2CH2OH → CH3CHCH2 → CH3CHBrCH2Br 1 electrophilic addition 2 nucleophilic substitution 3 free radical substitution

1 marks

Answer: A

This question in 9701/13 May/June 2017

3 Which fuel would produce the largest mass of CO2 when 10 kg of the fuel undergo complete combustion? A biodiesel, C17H34O2 B ethanol, C2H6O C octane, C8H18 D propane, C3H8

1 marks

Answer: C

This question in 9701/11 May/June 2018

21 Which equation represents a valid propagation step in the chlorination of ethane? A C2H6 + Cl • → C2H5Cl + H• B C2H5Cl + Cl • → C2H4Cl • + HCl C C2H5Cl + H• → C2H5• + HCl D C2H5• + Cl • → C2H5Cl

1 marks

Answer: B

This question in 9701/12 May/June 2018

31 For complete combustion, 1 mol of an organic compound X requires 2.5 mol of O2. Which compounds could be X? 1 C2H5OH 2 C2H2 3 CH3CHO

1 marks

Answer: C

This question in 9701/12 May/June 2018

3 A sample of the hydrocarbon C6H12 is completely burned in dry oxygen and the product gases are collected as shown. product gases, H2O + CO2 + excess of O2 excess of O2 P Q anhydrous soda lime calcium chloride (to absorb CO2) (to absorb H2O) The increases in mass of the collecting vessels P and Q are MP and MQ, respectively. What is the ratio MP / MQ? A 0.41 B 0.82 C 1.2 D 2.4

1 marks

Answer: A

This question in 9701/11 Oct/Nov 2018

24 An organic molecule W contains 3 carbon atoms. It requires 4.5 molecules of oxygen for complete combustion. What could W be? A propane B propanoic acid C propanone D propan-1-ol

1 marks

Answer: D

This question in 9701/11 Oct/Nov 2018

20 There are three structural isomers with the formula C5H12. Which formulae correctly represent these three structural isomers? A CH3CH2CH2CH2CH3 CH3CH(CH3)CH2CH3 C(CH3)4 B CH3CH2CH2CH2CH3 CH3CH(CH3)CH2CH3 CH3CH2CH(CH3)CH3 C D

1 marks

Answer: A

This question in 9701/12 Oct/Nov 2018

3 A sample of the hydrocarbon C6H12 is completely burned in dry oxygen and the product gases are collected as shown. product gases, H2O + CO2 + excess of O2 excess of O2 P Q anhydrous soda lime calcium chloride (to absorb CO2) (to absorb H2O) The increases in mass of the collecting vessels P and Q are MP and MQ, respectively. What is the ratio MP / MQ? A 0.41 B 0.82 C 1.2 D 2.4

1 marks

Answer: A

This question in 9701/13 Oct/Nov 2018

22 Many reactions take place in the engine and catalytic converter of a car. Which pair of substances is produced both by the reactions in a car engine and in a catalytic converter? A carbon dioxide and unburnt hydrocarbons B carbon dioxide and water C carbon monoxide and nitrogen D carbon monoxide and unburnt hydrocarbons

1 marks

Answer: B

This question in 9701/12 Feb/March 2019

21 Alkanes are saturated hydrocarbons. Which type of reaction are alkanes most likely to undergo? A electrophilic addition B electrophilic substitution C free radical substitution D nucleophilic addition

1 marks

Answer: C

This question in 9701/11 Oct/Nov 2019

21 Alkanes are saturated hydrocarbons. Which type of reaction are alkanes most likely to undergo? A electrophilic addition B electrophilic substitution C free radical substitution D nucleophilic addition

1 marks

Answer: C

This question in 9701/13 Oct/Nov 2019

25 Structural isomerism and stereoisomerism should be considered when answering this question. How many non-cyclic isomers have the molecular formula C5H10? A 3 B 4 C 5 D 6

1 marks

Answer: D

This question in 9701/12 Feb/March 2020

40 Which statements comparing ethene and ethane are correct? 1 The bond angles in ethene are larger than the bond angles in ethane. 2 Ethene reacts much more quickly with bromine in the dark than ethane does. 3 Complete combustion of 0.01 mol of ethene or ethane produces the same volume of gas measured at room temperature and pressure.

1 marks

Answer: A

This question in 9701/12 Feb/March 2020

6 In this question you should assume air contains 21% oxygen. What is the minimum volume of air required to ensure complete combustion of 10 cm3 of butane gas, under room conditions? A 14 cm3 B 27 cm3 C 65 cm3 D 310 cm3

1 marks

Answer: D

This question in 9701/12 May/June 2020

7 When aqueous bromine is shaken with cyclohexane and allowed to stand, two layers form. The top cyclohexane layer is coloured and the bottom aqueous layer is almost colourless. What is the most likely explanation for this observation? A Bromine is reduced to bromide ions in the bottom layer. B Bromine molecules are non-polar. C Bromine reacts with water but cannot react with cyclohexane. D The product of the reaction between bromine and cyclohexane is coloured.

1 marks

Answer: B

This question in 9701/12 May/June 2020

9 The complete combustion of 2 moles of an alkane produces 400 dm3 of carbon dioxide measured at 301 K and 1 × 105 Pa. Carbon dioxide can be assumed to behave as an ideal gas under these conditions. What is the formula of the alkane? A C8H18 B C16H34 C C20H42 D C40H82

1 marks

Answer: A

This question in 9701/12 May/June 2020

19 Most modern cars are fitted with catalytic converters in the exhaust system. Which three gases are removed by a catalytic converter? A carbon monoxide, hydrocarbons, nitrogen oxides B carbon monoxide, carbon dioxide, nitrogen oxides C carbon monoxide, nitrogen oxides, sulfur dioxide D hydrocarbons, nitrogen oxides, sulfur dioxide

1 marks

Answer: A

This question in 9701/12 May/June 2020

39 On complete combustion, a sample of X produces 44 g of carbon dioxide and 27 g of water. On complete combustion, a sample of Y produces 44 g of carbon dioxide and 18 g of water. On complete combustion, a sample of Z produces 22 g of carbon dioxide and 9 g of water. Which substances could be straight chain alkanes? 1 X 2 Y 3 Z

1 marks

Answer: D

This question in 9701/13 May/June 2020

22 Which statement is correct when referring to the complete combustion of PVC? A A gas is made which contributes to global warming. B Carbon dioxide and water are the only products. C If water is used to clean the exhaust gases, the water becomes alkaline. D There is no need to treat the exhaust gases as the products are non-hazardous.

1 marks

Answer: A

This question in 9701/11 Oct/Nov 2020

38 During the bromination of methane, the free radical CH3• is generated. A possible termination step of this reaction is the formation of C2H6 by the combination of two free radicals. What could be produced in a termination step during the bromination of propane? 1 CH3CH2CH(CH3)CH2CH3 2 CH3CH(CH3)CH(CH3)2 3 CH3CH2CH2CH(CH3)2

1 marks

Answer: C

This question in 9701/11 Oct/Nov 2020

28 Which statement about the use of alkane fuels in internal combustion engines is correct? A C8H18 is used as fuel in internal combustion engines and reacts with oxygen and nitrogen from the air. B In limited oxygen, CO is produced which oxidises SO2 to SO3 in the atmosphere. C The catalytic converter removes polluting gases including NO2 and CO2. D Unburnt hydrocarbons and NO2 can react in sunlight to produce photochemical smog.

1 marks

Answer: D

This question in 9701/12 Oct/Nov 2020

38 Which free radicals can be generated during a free-radical substitution reaction between chlorine and ethane? 1 CH3• 2 CH2Cl CH2• 3 CH3CCl 2•

1 marks

Answer: C

This question in 9701/12 Oct/Nov 2020

38 During the bromination of methane, the free radical CH3• is generated. A possible termination step of this reaction is the formation of C2H6 by the combination of two free radicals. What could be produced in a termination step during the bromination of propane? 1 CH3CH2CH(CH3)CH2CH3 2 CH3CH(CH3)CH(CH3)2 3 CH3CH2CH2CH(CH3)2

1 marks

Answer: C

This question in 9701/13 Oct/Nov 2020

3 Substance Q is a hydrocarbon. When 1.00 g of Q is completely burned, 3.22 g of carbon dioxide is produced. What could be the identity of Q? A cyclohexene B cyclopentane C ethene D pentane

1 marks

Answer: A

This question in 9701/12 Feb/March 2021

6 What is the minimum mass of oxygen required to ensure the complete combustion of 12 dm3 of propane measured under room conditions? A 60 g B 80 g C 120 g D 160 g

1 marks

Answer: B

This question in 9701/11 May/June 2021

23 Methane and bromine react by free radical substitution. P and Q are involved in the reaction mechanism. P and Q: ● are both involved in propagation steps as reactants ● are both involved in termination steps as reactants. What could be P and Q? A Br and H B Br and CH3 C Br and C2H6 D CH3 and CH3Br

1 marks

Answer: B

This question in 9701/12 May/June 2021

38 One molecule of dodecane, C12H26, is cracked, producing three product molecules, X, Y and Z. X is a straight chain alkane. Y and Z are straight chain alkenes with different Mr values. Which statements about X, Y and Z are correct? 1 If Y and Z are but-1-ene and ethene respectively, X will be hexane. 2 If X is butane, then Y and Z could both show cis-trans isomerism. 3 X could be octane.

1 marks

Answer: D

This question in 9701/11 Oct/Nov 2021

21 Bromomethane, CH3Br, decomposes in the stratosphere forming methyl free radicals and bromine free radicals. Which row correctly describes this decomposition? number of electrons in type of bond fission a bromine free radical A homolytic 35 B heterolytic 35 C homolytic 36 D heterolytic 36

1 marks

Answer: A

This question in 9701/12 Oct/Nov 2021

23 Which equation represents a valid propagation step in the chlorination of ethane? A C2H5Cl + Cl •  C2H4Cl • + HCl B C2H6 + Cl •  C2H5Cl + H• C C2H5Cl + H•  C2H5• + HCl D C2H5• + Cl •  C2H5Cl

1 marks

Answer: A

This question in 9701/12 Oct/Nov 2021

38 One molecule of dodecane, C12H26, is cracked, producing three product molecules, X, Y and Z. X is a straight chain alkane. Y and Z are straight chain alkenes with different Mr values. Which statements about X, Y and Z are correct? 1 If Y and Z are but-1-ene and ethene respectively, X will be hexane. 2 If X is butane, then Y and Z could both show cis-trans isomerism. 3 X could be octane.

1 marks

Answer: D

This question in 9701/13 Oct/Nov 2021

30 Oct-1-ene, CH3(CH2)5CH=CH2, can be thermally cracked. Which of the compounds W, X, Y and Z can be obtained by thermally cracking oct-1-ene? W X Y Z CH2=CH2 CH3CH=CH2 CH3CH2CH3 CH2=CHCH=CH2 A W, X, Y and Z B W, X and Y only C W, X and Z only D W and X only

1 marks

Answer: A

This question in 9701/11 May/June 2022

4 When a small sample of hydrocarbon Q is completely combusted, it produces 3.52 g of carbon dioxide and 1.44 g of water. What could be the structure of hydrocarbon Q? A B C D H C C C C H

1 marks

Answer: B

This question in 9701/12 May/June 2022

29 The free-radical substitution reaction between methane and chlorine involves initiation, propagation and termination stages. Which row is correct? involved in radical produced in initiation stage a propagation stage A homolytic fission H• B homolytic fission CH3• C heterolytic fission H• D heterolytic fission CH3•

1 marks

Answer: B

This question in 9701/12 May/June 2022

28 Which pair includes a hydrocarbon without a chiral centre? A CH3CH2CH2CH(CH3)CH2CH3 CH3CH(CH3)CH(CH3)CH2CH3 B CH3CH2CH2CH(CH2CH3)CH3 CH3CH2CH2CH(CH3)CH2CH3 C CH3CH2CH2CH(CH3)CH2CH3 CH3CH2CH(CH3)CH(CH3)2 D CH3CH(CH2CH3)CH(CH3)CH3 CH3CH(CH3)CH2CH(CH3)2

1 marks

Answer: D

This question in 9701/12 Oct/Nov 2022

31 A mixture of ethane and an excess of chlorine is exposed to UV light. How many different products, each containing only two carbon atoms and at least one chlorine atom per molecule, can be formed? A 8 B 9 C 10 D 12

1 marks

Answer: B

This question in 9701/13 May/June 2023

3 Aluminium carbide, Al 4C3, reacts readily with aqueous sodium hydroxide. The two products of the reaction are NaAlO2 and a hydrocarbon. Water molecules are also involved as reactants. What is the formula of the hydrocarbon? A CH4 B C2H6 C C3H8 D C6H12

1 marks

Answer: A

This question in 9701/11 Oct/Nov 2023

28 The hydrocarbon C17H36 can be cracked. Which compound is the least likely to be produced in this reaction? A C3H8 B C4H8 C C8H16 D C16H34

1 marks

Answer: D

This question in 9701/11 Oct/Nov 2023

32 Which list contains a compound that is not made during the free radical substitution of methane with chlorine? A CH3Cl, CCl 4, C2H6 B Cl 2, CH2Cl 2, CCl 4 C CH3Cl, CH2Cl 2, CHCl 3 D CH3Cl, CHCl 3, C2H2Cl 2

1 marks

Answer: D

This question in 9701/12 Oct/Nov 2023

28 The hydrocarbon C17H36 can be cracked. Which compound is the least likely to be produced in this reaction? A C3H8 B C4H8 C C8H16 D C16H34

1 marks

Answer: D

This question in 9701/13 Oct/Nov 2023

28 Which reaction occurs when ethane and chlorine are mixed in diffused sunlight? A a free-radical substitution with hydrogen given off B a free-radical substitution with hydrogen chloride given off C a free-radical substitution with no gas given off D a nucleophilic substitution with hydrogen chloride given off

1 marks

Answer: B

This question in 9701/11 May/June 2024

27 The alkane CH3CH2CH(CH3)2 undergoes free radical substitution with chlorine. No C–C bonds are broken in this reaction. How many isomeric products, including positional and optical isomers, of molecular formula C5H11Cl can be formed? A 4 B 5 C 6 D 7

1 marks

Answer: C

This question in 9701/13 May/June 2024

31 The reaction of chlorine with methane is carried out in the presence of light. What is the function of the light? A to break the C–H bonds in methane B to break the chlorine molecules into atoms C to break the chlorine molecules into ions D to heat the mixture

1 marks

Answer: B

This question in 9701/11 Oct/Nov 2024

31 The reaction of chlorine with methane is carried out in the presence of light. What is the function of the light? A to break the C–H bonds in methane B to break the chlorine molecules into atoms C to break the chlorine molecules into ions D to heat the mixture

1 marks

Answer: B

This question in 9701/13 Oct/Nov 2024

37 A molecule of hexane can be cracked in a number of different ways. Three compounds are listed. 1 C3H8 2 C4H8 3 C5H12 Which compounds are found in the mixture of products from the cracking of hexane molecules? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: B

This question in 9701/12 Feb/March 2025

37 Three substances are listed. 1 butane 2 hydrogen 3 hydrogen bromide Which substances are possible products of the free-radical substitution reaction between ethane and bromine? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: C

This question in 9701/11 May/June 2025

35 Samples of the gases CH3Cl and Cl 2 are mixed together and irradiated with ultraviolet light. Which compound is produced by a termination step in the reaction? A HCl B CH2=CH2 C CH2Cl CH2Cl D H2

1 marks

Answer: C

This question in 9701/12 May/June 2025

37 Alkane S has molecular formula C4H10. S reacts with Cl 2(g) in the presence of sunlight to produce only two different monochloroalkanes, C4H9Cl. Both of these monochloroalkanes are treated with hot ethanolic KOH. They both produce the same alkene T, and no other organic products. What is produced when T is treated with hot concentrated acidified KMnO4? A CO2 and CH3CH2CO2H B CO2 and CH3COCH3 C HCO2H and CH3COCH3 D CH3CO2H only

1 marks

Answer: B

This question in 9701/12 May/June 2025

36 Two steps in the free-radical substitution reaction between methane and chlorine are shown. step 1 CH3• + Cl2 CH3Cl + Cl• step 2 CH3Cl + Cl•  CH2Cl• + HCl Which statement is correct? A Step 1 is initiation and step 2 is propagation. B Step 1 is propagation and step 2 is termination. C Step 1 is initiation and step 2 is termination. D Both steps are propagation.

1 marks

Answer: D

This question in 9701/13 May/June 2025

28 Two hydrocarbons, R–CH3 and R'–CH3, react separately with bromine in the presence of ultraviolet light. One of these hydrocarbons is unsaturated. In each case, free radical substitution reactions occur. R is CH3CHC(CH3). R' is CH3CH(CH3)CH2. Which row is correct? a propagation stage for the saturated hydrocarbon a termination stage for the unsaturated hydrocarbon A R–CH2• + Br•  R–CH2Br R'–CH2• + Br•  R'–CH2Br B R–CH2• + Br2 R–CH2Br + Br• R'–CH2• + Br2 R'–CH2Br + Br• C R'–CH3 + Br•  R'–CH2• + HBr 2R–CH2•  R–CH2CH2–R D 2R'–CH2•  R'–CH2CH2–R' R–CH3 + Br•  R–CH2• + HBr

1 marks

Answer: C

This question in 9701/11 Oct/Nov 2025

29 The fumes from the exhausts of petrol-burning cars contain the following pollutants. 1 unburnt hydrocarbons 2 nitrogen dioxide 3 carbon monoxide Which pollutants are removed by oxidation in a catalytic converter? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: C

This question in 9701/11 Oct/Nov 2025

28 Two hydrocarbons, R–CH3 and R'–CH3, react separately with bromine in the presence of ultraviolet light. One of these hydrocarbons is unsaturated. In each case, free radical substitution reactions occur. R is CH3CHC(CH3). R' is CH3CH(CH3)CH2. Which row is correct? a propagation stage for the saturated hydrocarbon a termination stage for the unsaturated hydrocarbon A R–CH2• + Br•  R–CH2Br R'–CH2• + Br•  R'–CH2Br B R–CH2• + Br2 R–CH2Br + Br• R'–CH2• + Br2 R'–CH2Br + Br• C R'–CH3 + Br•  R'–CH2• + HBr 2R–CH2•  R–CH2CH2–R D 2R'–CH2•  R'–CH2CH2–R' R–CH3 + Br•  R–CH2• + HBr

1 marks

Answer: C

This question in 9701/13 Oct/Nov 2025

29 The fumes from the exhausts of petrol-burning cars contain the following pollutants. 1 unburnt hydrocarbons 2 nitrogen dioxide 3 carbon monoxide Which pollutants are removed by oxidation in a catalytic converter? A 1, 2 and 3 B 1 and 2 only C 1 and 3 only D 2 and 3 only

1 marks

Answer: C

This question in 9701/13 Oct/Nov 2025