Chemistry Unit Two (F322) Chains, Energy and Resources

Transcription

1 hemistry Unit Two (F322) hains, Energy and Resources

2 Past Paper Self Assessment alendar - hemistry Unit 2 Date questions and SEF completed 30 Mar - 3 Apr Easter Break 6 Apr - 10 Apr Jan Apr - 17 Apr Apr - 24 Apr 31 Jun Apr - 1 May 32 3 May - 8 May 33 Jun May - 15 May 17 May - 22 May May 29 May 35 Mid Term Break Jan May - 4 Jun mchem.weebly.com

3 hemistry Unit 1 Self-Evaluation Form and Action Plan Year Question Mark (SA) Strength Target May Action plan (What I need to do to achieve target)

4 hemistry Unit 1 Self-Evaluation Form and Action Plan Year Question Mark (SA) Strength Target Jan Action plan (What I need to do to achieve target)

5 hemistry Unit 1 Self-Evaluation Form and Action Plan Year Question Mark (SA) Strength Target Jun Action plan (What I need to do to achieve target)

6 hemistry Unit 1 Self-Evaluation Form and Action Plan Year Question Mark (SA) Strength Target Jan Action plan (What I need to do to achieve target)

7 Wednesday 23 May 2012 Afternoon AS GE EMISTRY A F322 hains, Energy and Resources *F * andidates answer on the Question Paper. OR supplied materials: Data Sheet for hemistry A (inserted) Other materials required: Scientific calculator Duration: 1 hour 45 minutes * F * INSTRUTIONS TO ANDIDATES The Insert will be found in the centre of this document. Write your name, centre number and candidate number in the boxes above. Please write clearly and in capital letters. Use black ink. B pencil may be used for graphs and diagrams only. Answer all the questions. Read each question carefully. Make sure you know what you have to do before starting your answer. Write your answer to each question in the space provided. Additional paper may be used if necessary but you must clearly show your candidate number, centre number and question number(s). Do not write in the bar codes. INFORMATION FOR ANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. Where you see this icon you will be awarded marks for the quality of written communication in your answer. This means for example you should: ensure that text is legible and that spelling, punctuation and grammar are accurate so that meaning is clear; organise information clearly and coherently, using specialist vocabulary when appropriate. You may use a scientific calculator. A copy of the Data Sheet for hemistry A is provided as an insert with this question paper. You are advised to show all the steps in any calculations. The total number of marks for this paper is 100. This document consists of 20 pages. Any blank pages are indicated. OR 2012 [/500/7834] D (NF/SW) 40574/5 OR is an exempt harity Turn over

8 2 Answer all the questions. 1 rude oil is a source of many important petrochemicals. The flow chart shows some of the petrochemicals that can be made and the processes used to make them. crude oil fractional distillation bitumen liquid fuels e.g. petrol and diesel naphtha gaseous fuels e.g. methane and butane cracking ethene petrochemicals e.g. polymers and pharmaceuticals bromoethane ethanol 1,2-dibromoethane (a) Explain why crude oil can be separated into different fractions [1] (b) Many scientists believe that we should use more fuels such as biodiesel or bio-ethanol rather than petrol and diesel. Suggest one reason why these scientists take this view [1] OR 2012

9 3 (c) racking converts the alkane dodecane, 12 26, into more useful short chain alkanes and alkenes. (i) When is cracked, a variety of alkanes and alkenes are formed with different chain lengths. Explain why a variety of alkanes and alkenes are formed with different chain lengths.... [1] (ii) One molecule of is cracked to produce one molecule of propane and several molecules of an alkene, A. The mass spectrum of A contains peaks with the following m /z values: 15, 27 and 42. There are no m /z values above 42. Write the formula of the particle responsible for the peak at m /z = 27. Identify, with a reason, alkene A. Write an equation to show this cracking of to form alkene A.... [4] OR 2012 Turn over

10 (d) Ethene can be converted into petrochemicals. 4 Describe how ethene can be converted into 1,2-dibromoethane, bromoethane and ethanol. Name and describe the mechanism for the conversion of ethene into 1,2-dibromoethane using the curly arrow model. Include any relevant dipoles [9] OR 2012

11 (e) Draw and explain the shape of an ethene molecule. State the bond angle in ethene [3] (f) Addition polymers are made by the polymerisation of alkenes. E-Pent-2-ene can be made into an addition polymer. (i) Draw the structure of E-pent-2-ene. [1] (ii) Draw the structure of poly(pent-2-ene). Include two repeat units. [1] [Total: 21] OR 2012 Turn over

12 6 2 Epoxyethane, 2 4 O, is a synthetic intermediate that is used to make ethane-1,2-diol and some polymers. The structure of epoxyethane is shown below. O (a) The controlled catalysed reaction of ethene with oxygen forms epoxyethane as the only product. (i) Write the equation for this reaction. [1] (ii) When burnt in excess oxygen, ethene completely combusts. Write the equation for the complete combustion of ethene.... [1] (b) Epoxyethane reacts with water in the presence of an acid catalyst to form ethane-1,2-diol. + 2 O O The mechanism for this reaction is shown below. O O step 1 step 2 + O + O O O + step 3 step 4 OR 2012 O + O O O +

13 (i) 7 Draw dipoles on the carbon and oxygen atoms on the displayed formula of epoxyethane. (ii) The mechanism uses the curly arrow model. What does a curly arrow represent? O [1]... [1] (iii) What type of bond fission occurs in step 2? Explain your answer.... [2] (iv) ow can you tell that water is behaving as a nucleophile in step 3?... [1] (v) ow does the mechanism show that + ions act as a catalyst in this reaction? Refer to the steps in the mechanism in your answer.... [1] (vi) Epoxyethane reacts with methanol, 3 O, to form a compound with the molecular formula 3 8 O 2. Suggest the structure of this compound. OR 2012 Turn over [1]

14 (c) Ethane-1,2-diol is much less volatile than ethanol. Suggest why [2] (d) Ethane-1,2-diol reacts with an excess of ethanoic acid, 3 OO, in the presence of an acid catalyst. A compound is formed with the molecular formula 6 10 O 4. Draw the structure of this compound. (e) Ethane-1,2-diol reacts with warm acidified potassium dichromate(vi). A number of different organic products are formed. Draw the displayed formulae of two of these organic products. [2] [2] [Total: 15] OR 2012

15 3 ydrogen has many industrial uses including making margarine and ammonia. ydrogen can be made by the reaction between methane and steam. 9 4 (g) + 2 O(g) O(g) (g) Δ = +210 kj mol 1 (a) The pressure of the equilibrium mixture is increased. Explain what happens to the position of the equilibrium [2] (b) The temperature of the equilibrium mixture is increased. Explain what happens to the position of the equilibrium [2] (c) The reaction is actually carried out in the presence of a nickel catalyst at a pressure of 30 atmospheres. (i) Suggest why the manufacturer uses a pressure of 30 atmospheres.... [1] OR 2012 Turn over

16 (ii) 10 The nickel catalyst increases the rate. Use a labelled diagram of the Boltzmann distribution of molecular energies to explain why.... [3] (d) A chemical factory uses 200 tonnes of methane a day. The factory produces 68.4 tonnes of hydrogen per day by reacting methane with steam. 4 (g) + 2 O(g) O(g) (g) alculate the percentage yield of hydrogen. Give your answer to three significant figures. (1 tonne = g) percentage yield of hydrogen =... % [3] OR 2012

17 11 (e) The carbon monoxide produced in the equation below can be reacted with hydrogen to make methanol. 4 (g) + 2 O(g) O(g) (g) (i) onstruct the equation for the reaction of carbon monoxide with hydrogen to make methanol.... [1] (ii) Suggest two reasons why it is important to use the carbon monoxide to make methanol.... [2] (f) Describe how hydrogen can be used in the manufacture of margarine [2] [Total: 16] OR 2012 Turn over

18 12 4 The uses of catalysts have great economic and environmental importance. For example, catalysts are used in ammonia production and in catalytic converters. (a) Nitrogen and hydrogen react together in the production of ammonia, N 3. N 2 (g) (g) 2N 3 (g) Δ = 92 kj mol 1 The activation energy for the forward reaction, E a, is +250 kj mol 1. (i) omplete the enthalpy profile diagram for this reaction between nitrogen and hydrogen. Include the products enthalpy change of reaction, Δ activation energy for the forward reaction, E a. enthalpy N 2 (g) (g) progress of reaction [3] (ii) What is the value of the enthalpy change of formation of ammonia? answer =... kj mol 1 [1] (iii) The reaction between nitrogen and hydrogen can be catalysed. Suggest a possible value for the activation energy of the catalysed forward reaction. answer =... kj mol 1 [1] (iv) What is the value of the activation energy for the uncatalysed reverse reaction (the decomposition of ammonia into nitrogen and hydrogen)? answer =... kj mol 1 [1] OR 2012

19 (b) In a catalytic converter, nitrogen monoxide reacts with carbon monoxide. 13 (i) Write the equation for this reaction.... [1] (ii) Outline the stages that allow nitrogen monoxide and carbon monoxide to react in a catalytic converter.... [3] (c) Scientists monitor pollutant gases in the atmosphere. (i) State two modern analytical techniques that scientists can use to monitor environmental pollution.... [2] (ii) Explain why it is important to establish international cooperation to reduce pollution levels.... [1] OR 2012 Turn over

20 14 (d) In the stratosphere, nitrogen monoxide, NO, is linked with ozone depletion. omplete the equations below that describe how NO contributes to ozone depletion. step 1 NO + O step 2 NO NO +... overall O 2 [3] (e) ess law can be used to calculate enthalpy changes of reaction. The equation for the reaction that gives the enthalpy change of formation, Δ f, of N 2 O(g) is as follows. N 2 (g) + ½O 2 (g) N 2 O(g) (i) It is not possible to measure the enthalpy change of formation of N 2 O(g) directly. Suggest why it is not possible.... [1] (ii) The data below can be used to calculate the enthalpy change of formation, Δ f, of N 2 O(g). reaction enthalpy change of reaction / kj mol 1 (s) + N 2 O(g) O(g) + N 2 (g) 193 (s) + ½O 2 (g) O(g) 111 alculate Δ f for N 2 O(g). Δ f =... kj mol 1 [2] [Total: 19] OR 2012

21 5 Methane and ethane are important fuels. 15 (a) Methane could be manufactured by the reaction between carbon dioxide and hydrogen. O 2 (g) (g) 4 (g) O(g) Using the table of bond enthalpies, calculate the enthalpy change of reaction for this manufacture of methane. bond average bond enthalpy / kj mol =O +805 O +464 enthalpy change of reaction =... kj mol 1 [3] OR 2012 Turn over

22 16 (b) Methane is a greenhouse gas. Scientists are concerned that the concentration of methane in the atmosphere is slowly increasing. (i) Explain how atmospheric methane molecules can contribute to global warming.... [2] (ii) One way that scientists hope to minimise global warming is by developing arbon apture and Storage, S, techniques. Describe two of these S techniques.... [2] OR 2012

23 17 (c) Ethane reacts with bromine in the presence of ultraviolet radiation to form many organic products. (i) Two of these products are bromoethane and hydrogen bromide. Describe the mechanism of the reaction between ethane and bromine that forms bromoethane and hydrogen bromide. Include in your answer the type of bond fission that occurs equations for each step of the reaction the name of each step of the reaction. Your answer needs to be clear and well organised using the correct terminology.... [7] (ii) Give two reasons why there are many organic products of the reaction between bromine and ethane.... [2] [Total: 16] OR 2012 Turn over

24 6 A student carries out an investigation on some halogenoalkanes. 18 (a) She decided to hydrolyse 1-bromopentane and 1-chloropentane using aqueous sodium hydroxide. State and explain the difference in the rates of hydrolysis of 1-bromopentane and 1-chloropentane [2] (b) A student wants to determine the structure of an unknown iodoalkane B. She knows that the molecular formula of B is 4 9 I. The student heats B with aqueous sodium hydroxide. A reaction mixture forms containing the organic compound and I (aq). (i) Draw all of the possible structural isomers for B. (ii) What is the molecular formula for compound?... [1] [4] (iii) The student purifies compound and splits it into two portions. She heats one portion of with concentrated sulfuric acid. The product of this reaction is methylpropene. To the other portion of, she adds acidified potassium dichromate(vi) and heats the mixture under reflux. The product of this reaction is compound D. The infrared spectrum for compound D is shown at the top of page 19. OR 2012

25 transmittance (%) wavenumber / cm Use this evidence to suggest structures for B, and D. In your answer you should make clear how your explanations are linked to the evidence. OR 2012 Turn over

26 20... [6] [Total: 13] END OF QUESTION PAPER opyright Information OR is committed to seeking permission to reproduce all third-party content that it uses in its assessment materials. OR has attempted to identify and contact all copyright holders whose work is used in this paper. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced in the OR opyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download from our public website ( after the live examination series. If OR has unwittingly failed to correctly acknowledge or clear any third-party content in this assessment material, OR will be happy to correct its mistake at the earliest possible opportunity. For queries or further information please contact the opyright Team, First Floor, 9 ills Road, ambridge B2 1GE. OR is part of the ambridge Assessment Group; ambridge Assessment is the brand name of University of ambridge Local Examinations Syndicate (ULES), which is itself a department of the University of ambridge. OR 2012

27 Thursday 19 January 2012 Afternoon AS GE EMISTRY A F322 hains, Energy and Resources *F * andidates answer on the Question Paper. OR supplied materials: Data Sheet for hemistry A (inserted) Other materials required: Scientific calculator Duration: 1 hour 45 minutes * F * INSTRUTIONS TO ANDIDATES The Insert will be found in the centre of this document. Write your name, centre number and candidate number in the boxes above. Please write clearly and in capital letters. Use black ink. B pencil may be used for graphs and diagrams only. Answer all the questions. Read each question carefully. Make sure you know what you have to do before starting your answer. Write your answer to each question in the space provided. If additional space is required, you should use the lined pages at the end of this booklet. The question number(s) must be clearly shown. Do not write in the bar codes. INFORMATION FOR ANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. Where you see this icon you will be awarded marks for the quality of written communication in your answer. This means for example you should: ensure that text is legible and that spelling, punctuation and grammar are accurate so that meaning is clear; organise information clearly and coherently, using specialist vocabulary when appropriate. You may use a scientific calculator. A copy of the Data Sheet for hemistry A is provided as an insert with this question paper. You are advised to show all the steps in any calculations. The total number of marks for this paper is 100. This document consists of 24 pages. Any blank pages are indicated. OR 2012 [/500/7834] D (LEO/SW) 40572/6 OR is an exempt harity Turn over

28 2 Answer all the questions. 1 rude oil is a source of many hydrocarbons. The skeletal formulae of some of these hydrocarbons are shown below. A B D E F G I (a) Explain why compound A is both saturated and a hydrocarbon [2] (b) What is the empirical formula for compound A?... [1] (c) Give the letters, A, B,, D, E, F, G, or I, of two hydrocarbons that are structural isomers of each other.... and... [1] OR 2012

29 3 (d) The petroleum industry processes straight chain alkanes into cyclic hydrocarbons such as A, B and E. (i) Explain why the petroleum industry processes straight chain alkanes into cyclic hydrocarbons.... [1] (ii) ydrocarbon can be processed into the cyclic hydrocarbon B. onstruct an equation for this reaction. [1] (e) Explain why hydrocarbon D has a higher boiling point than hydrocarbon [2] (f) ydrocarbons G and are stereoisomers of each other. Explain what is meant by the term stereoisomerism [2] (g) onstruct the equation for the complete combustion of hydrocarbon.... [2] OR 2012 Turn over

30 4 (h) A hydrocarbon molecule, 16 34, is cracked to form an octane molecule and two molecules of but-2-ene. onstruct the equation for this reaction.... [1] (i) ompound I is 3-methylheptane. It does not contain a functional group. I (i) What is meant by the term functional group?... [1] (ii) ompound I reacts with chlorine in the presence of ultraviolet radiation to give several structural isomers of 8 17 l. ow many structural isomers could be formed in this reaction?... [1] (iii) The mechanism of the reaction involves radicals. What is meant by the term radical?... [1] [Total: 16] OR 2012

31 2 Ethanoic acid, 3 OO, is used to make esters. Some information about two of the processes used to make ethanoic acid is given below. 5 Process 1 This is a one-step process that involves the reaction of methanol with carbon monoxide. 3 O + O 3 OO The conditions used are 180 and 30 atmospheres pressure. A rhodium/iodine catalyst is used. The percentage yield for this process is 99%. Process 2 This involves the oxidation of naphtha, a fraction obtained from crude oil. Liquid naphtha is oxidised using air at a temperature of 180 and 50 atmospheres pressure. No catalyst is needed. A large variety of other products are also formed in this oxidation. (a) Suggest three advantages of making ethanoic acid using Process 1 rather than Process [3] OR 2012 Turn over

32 6 (b) The other products formed in Process 2 are carboxylic acids, aldehydes and ketones. A research chemist investigates some of these other products of Process 2. (i) The research chemist isolates product, J. The infrared spectrum of J is shown below. 100 transmittance (%) wavenumber / cm The chemist also finds that g of a pure sample of J contains mol of J. Suggest, with reasons, one possible structure for J. In your answer you should link the evidence with your explanation.... [5] OR 2012

33 7 (ii) The chemist isolates another product, the carboxylic acid, K. K has the molecular formula 4 8 O 2. Suggest a possible structure and name for K. structure name... [2] (c) Ethanoic acid is used in the manufacture of the ester, propyl ethanoate. Describe how ethanoic acid is converted into propyl ethanoate. Include an equation in your answer [4] [Total: 14] OR 2012 Turn over

34 3 Enthalpy changes can be determined directly or indirectly. (a) A student investigates the reaction between magnesium and dilute hydrochloric acid. 8 Mg(s) + 2l(aq) Mgl 2 (aq) + 2 (g) The student determines the enthalpy change for this reaction. In her experiment, she reacts g of magnesium with 50.0 cm 3 of 2.00 mol dm 3 l(aq). The l(aq) is in excess. The temperature of the solution changes from 19.2 to (i) alculate the energy released, in kj, during this reaction. The specific heat capacity of the solution = 4.18 J g 1 K 1. The density of the solution is 1.00 g cm 3. energy =...kj [2] (ii) alculate the amount, in moles, of magnesium used by the student. amount =... mol [1] (iii) alculate the enthalpy change of reaction. Give your answer to three significant figures. enthalpy change of reaction =...kj mol 1 [3] OR 2012

35 9 (b) The student wants to determine the enthalpy change of formation of calcium carbonate, ao 3 (s). a(s) + (s) + 1½O 2 (g) ao 3 (s) (i) What is meant by the term standard enthalpy change of formation? You should state the standard conditions in your answer.... [3] (ii) Using the following data and enthalpy cycle, fill in the boxes on the enthalpy cycle with the correct enthalpy change values calculate the enthalpy change of formation, Δ f, of ao 3 (s). reaction enthalpy change, Δ / kj mol 1 (s) + O 2 (g) O 2 (g) (g) + ½O 2 (g) 2 O(l) 285 ao 3 (s) + 2l(aq) al 2 (aq) + 2 O(l) + O 2 (g) 54 a(s) + 2l(aq) al 2 (aq) + 2 (g) 168 a(s) + 2l(aq) + (s) + 1½O 2 (g) f ao 3 (s) + 2l(aq)... al 2 (aq) + 2 (g) + (s) + 1½O 2 (g) al 2 (aq) + 2 O(I) + (s) + O 2 (g) al 2 (aq) + 2 O(I) + O 2 (g)... Δ f =... kj mol 1 [3] OR 2012 [Total: 12] Turn over

36 10 4 ydrogen and chlorine are reacted together to form hydrogen chloride. 2 (g) + l 2 (g) 2l(g) Δ = 184 kj mol 1 (a) alculate the bond enthalpy for the l bond using the information in the table below. bond bond enthalpy / kj mol l l +243 bond enthalpy =... kj mol 1 [2] (b) The reaction is repeated at a higher pressure. Describe and explain what happens to the rate of the reaction between 2 (g) and l 2 (g) [2] OR 2012

37 (c) The reaction is repeated again. This time the temperature is decreased. 11 Describe and explain, by drawing appropriately labelled Boltzmann distributions, what happens to the rate of reaction between 2 (g) and l 2 (g) [5] (d) The mechanism of the reaction between 2 (g) and l 2 (g) involves initiation, propagation and termination. (i) The initiation step is the homolytic fission of the covalent bond in a chlorine molecule. Write an equation to show this homolytic fission.... [1] (ii) omplete the following equations which show the propagation steps. l l [2] (iii) Suggest equations for two termination steps.... [2] [Total: 14] OR 2012 Turn over

38 5 Sulfuric acid is made from sulfur, oxygen and water in a three-stage process. This can be represented by the following overall equation. 12 2S(s) + 3O 2 (g) O(l) 2 2 SO 4 (l) (a) Explain why the overall process to make sulfuric acid has an atom economy of 100% [1] (b) A factory uses 51.4 tonnes of sulfur to manufacture 147 tonnes of 2 SO 4. What is the percentage yield of 2 SO 4? Give your answer to two significant figures. (1 tonne = g) percentage yield =... % [3] OR 2012

39 13 (c) One of the reactions involved in making sulfuric acid converts sulfur dioxide, SO 2, into sulfur trioxide, SO 3. 2SO 2 (g) + O 2 (g) 2SO 3 (g) Δ = 197 kj mol 1 This reaction can be carried out at 450 and 3 atmospheres pressure in the presence of a V 2 O 5 catalyst. Under these conditions the position of equilibrium is almost completely on the right-hand side. (i) A research chemist investigates this reaction. e uses a temperature of 450 and 3 atmospheres pressure. The research chemist does not use the catalyst. Predict the changes, if any, on each of the following. position of equilibrium... rate of backward reaction... [2] (ii) The temperature of the reaction mixture is increased to 600. State and explain what will happen to the position of equilibrium.... [1] (iii) The pressure of the reaction mixture is decreased to 2 atmospheres. State and explain what will happen to the position of equilibrium.... [1] OR 2012 Turn over

40 14 (d) oncentrated 2 SO 4 is used as an acid catalyst in the elimination of water from alcohols. There are several alcohols that are structural isomers with the formula 5 11 O. When these alcohols are heated with 2 SO 4 they form alkenes O O (i) Pentan-1-ol is a structural isomer of 5 11 O that is a primary alcohol. Draw the structure of another structural isomer of 5 11 O that is a primary alcohol. [1] (ii) Pentan-2-ol is a structural isomer of 5 11 O that is a secondary alcohol. Pentan-2-ol is heated with 2 SO 4. Three alkenes are formed, L, M and N. L and M are stereoisomers. N is a structural isomer of the stereoisomers L and M. Draw the structures for alkenes L, M and N. alkene L alkene M alkene N [3] OR 2012

41 (iii) 15 One structural isomer of 5 11 O is an alcohol that cannot be oxidised by heating with acidified potassium dichromate(vi). Draw the structure of this alcohol. [1] [Total: 13] OR 2012 Turn over

42 6 Mass spectrometry is used in analysis. 16 (a) ompound O contains carbon, hydrogen and oxygen. The mass spectrum of compound O is shown below relative abundance (%) m / z (i) Identify the m/z value that corresponds to the molecular ion.... [1] (ii) Write the formula of the ion that gives rise to the peak at m / z = [1] (iii) Suggest the molecular formula for O.... [1] OR 2012

43 17 (b) A scientist analyses a sample of Moon rock. She uses mass spectrometry to find out which metal the sample contains. The mass spectrum of the sample shows m/z peaks as shown in the table. m/z value percentage abundance (%) Positive ions, X +, of the metal were responsible for the two m/z peaks. Identify the metal X by calculating its relative atomic mass to one decimal place. relative atomic mass of X =... metal X =... [3] [Total: 6] OR 2012 Turn over

44 18 7 hlorofluorocarbons, Fs, were once used as propellants in aerosols. Fs contribute to ozone depletion in the upper atmosphere. (a) A F has the formula F 2 l 2. State the three-dimensional shape of a F 2 l 2 molecule and the F l bond angle. shape... bond angle... [2] (b) Two reasons that F 2 l 2 was used as an aerosol propellant are that it has low reactivity and will not hydrolyse in water. (i) State one other reason why F 2 l 2 was developed for use as an aerosol.... [1] (ii) Suggest why F 2 l 2 does not hydrolyse in water.... [1] (c) Explain, with the aid of equations, how the presence of Fs in the upper atmosphere leads to ozone depletion [3] (d) Why are scientists concerned about ozone depletion? [1] OR 2012

45 19 (e) International agreements have reduced the use of Fs. owever the concentration of atmospheric Fs has hardly changed. Suggest two reasons why [2] [Total: 10] OR 2012 Turn over

46 8 yclopentene is a cyclic alkene. 20 (a) The flowchart shows some reactions involving cyclopentene and cyclopentanol. omplete the partial structures in the boxes to show compounds P, Q and R, the main organic products of the reactions. O K 2 r 2 O 7 (aq) / 2 SO 4 (aq) reflux cyclopentanol compound P cyclopentene Br 2 2 with Ni catalyst compound Q compound R [3] (b) What would be the colour change in the reaction between cyclopentene and bromine?... to... [1] OR 2012

47 21 (c) yclopentene can be polymerised to give poly(cyclopentene). Draw a section of poly(cyclopentene) to show two repeat units. [1] (d) yclopentene reacts with l by electrophilic addition. Use the curly arrow model to complete the mechanism for this reaction. In your answer include any relevant dipoles, the intermediate and the product l intermediate product [5] TURN OVER FOR QUESTION 8(e) OR 2012 Turn over

48 (e) hlorocyclopentane can be hydrolysed by heating with aqueous sodium hydroxide l + NaO O + Nal Use the curly arrow model to complete the mechanism for this hydrolysis reaction. Include in your answer, relevant dipoles, the name of the mechanism and the type of bond fission. In your answer you should use the correct technical terms, spelled correctly l 2 2 O +... O products name of mechanism... type of bond fission... [5] [Total: 15] END OF QUESTION PAPER OR 2012

49 23 ADDITIONAL PAGE If additional space is required, you should use the lined pages below. The question number(s) must be clearly shown OR 2012

50 24 ADDITIONAL PAGE opyright Information OR is committed to seeking permission to reproduce all third-party content that it uses in its assessment materials. OR has attempted to identify and contact all copyright holders whose work is used in this paper. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced in the OR opyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download from our public website ( after the live examination series. If OR has unwittingly failed to correctly acknowledge or clear any third-party content in this assessment material, OR will be happy to correct its mistake at the earliest possible opportunity. For queries or further information please contact the opyright Team, First Floor, 9 ills Road, ambridge B2 1GE. OR is part of the ambridge Assessment Group; ambridge Assessment is the brand name of University of ambridge Local Examinations Syndicate (ULES), which is itself a department of the University of ambridge. OR 2012

51 ADVANED SUBSIDIARY GE EMISTRY A hains, Energy and Resources F322 *OE/23212* andidates answer on the question paper. OR Supplied Materials: Data Sheet for hemistry A (inserted) Other Materials Required: Scientific calculator Thursday 20 January 2011 Afternoon Duration: 1 hour 45 minutes * F * INSTRUTIONS TO ANDIDATES The insert will be found in the centre of this document. Write your name, centre number and candidate number in the boxes above. Please write clearly and in capital letters. Use black ink. Pencil may be used for graphs and diagrams only. Read each question carefully. Make sure you know what you have to do before starting your answer. Write your answer to each question in the space provided. If additional space is required, you should use the lined pages at the end of this booklet. The question number(s) must be clearly shown. Answer all the questions. Do not write in the bar codes. INFORMATION FOR ANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. Where you see this icon you will be awarded marks for the quality of written communication in your answer. This means for example you should: ensure that text is legible and that spelling, punctuation and grammar are accurate so that meaning is clear; organise information clearly and coherently, using specialist vocabulary when appropriate. You may use a scientific calculator. A copy of the Data Sheet for hemistry A is provided as an insert with this question paper. You are advised to show all the steps in any calculations. The total number of marks for this paper is 100. This document consists of 24 pages. Any blank pages are indicated. OR 2011 [/500/7834] D (SJF5669/SW) 23212/4 OR is an exempt harity Turn over

52 2 BLANK PAGE PLEASE DO NOT WRITE ON TIS PAGE OR 2011

53 3 Answer all the questions. 1 rude oil is a source of alkanes. (a) Fractional distillation is used to separate useful hydrocarbons found in crude oil. Explain, in terms of intermolecular forces, how fractional distillation works [2] (b) The petroleum industry processes straight-chained alkanes into cycloalkanes such as cyclopentane and cyclohexane cyclopentane cyclohexane (i) Deduce the general formula of a cycloalkane.... [1] (ii) onstruct the equation to show the formation of cyclohexane from hexane. [1] (iii) Suggest why the petroleum industry processes hexane into cyclohexane. OR [1] Turn over

54 4 (c) The flowchart below shows some of the organic compounds that could be made starting from cyclohexane. l 2 / UV l chlorocyclohexane KO(aq) / warm compound A K 2 r 2 O 7 (aq) 3 PO 4 / heat 2 SO 4 (aq) O cyclohexanol cyclohexene Br Br 2 compound B Br Br (i) Explain why cyclohexene is described as unsaturated and as a hydrocarbon.... [2] (ii) The reaction between chlorine and cyclohexane is an example of radical substitution. State one problem of using this reaction to prepare a sample of chlorocyclohexane.... [1] OR 2011

55 (iii) 5 The formation of cyclohexanol from chlorocyclohexane involves the reaction of a nucleophile, the hydroxide ion. Suggest what feature of the hydroxide ion makes it able to act as a nucleophile.... [1] (iv) Using the flowchart, draw the structures of compound A and compound B. compound A compound B [2] (v) Describe, using the curly arrow model, the mechanism for the reaction between Br 2 and cyclohexene. Show relevant dipoles and charges. 2 2 Br 2 2 Br [4] [Total: 15] OR 2011 Turn over

56 2 Butyl ethanoate is an ester used as a flavouring. This ester can be synthesised from butan-1-ol by two different processes. Process 1 is a one-step process that involves a reversible reaction O + 3 OO 3 OO O The percentage yield for process 1 is 67.1%. The atom economy for process 1 is 86.6%. Process 2 is a two-step process. 3 OO + SOl 2 3 Ol + SO 2 + l O + 3 Ol 3 OO l The overall percentage yield for process 2 is 93.3%. The overall atom economy for process 2 is 45.8%. (a) Draw the skeletal formula for the ester butyl ethanoate. [1] (b) Show that the atom economy for process 1 is 86.6%. [2] OR 2011

57 (c) A research chemist investigates process 1. She finds that 6.25 g of butan-1-ol forms 6.57 g of butyl ethanoate. 7 (i) Suggest the conditions needed for this reaction.... [2] (ii) Show that the percentage yield of process 1 is 67.1%. (d) Explain why process 2 has a high percentage yield but a low atom economy [2] (e) Suggest two reasons why butyl ethanoate is manufactured by process 1 rather than by process [2] [2] [Total: 11] OR 2011 Turn over

58 3 Enthalpy changes of reaction can be determined by experiment or by using bond enthalpies. (a) What is meant by the term enthalpy change of reaction? [2] (b) Solid ammonium thiocyanate, N 4 SN, reacts with solid barium hydroxide, Ba(O) 2, as shown in the equation below. 2N 4 SN(s) + Ba(O) 2 (s) Ba(SN) 2 (s) O(l) + 2N 3 (g) A research chemist carries out an experiment to determine the enthalpy change of this reaction. thermometer boiling tube 50.0g of water mixture of ammonium thiocyanate and barium hydroxide insulated beaker In the experiment, g of N 4 SN is reacted with a slight excess of Ba(O) 2. The reaction absorbs energy, cooling the 50.0 g of water from 21.9 to (i) alculate the energy absorbed, in kj, during this reaction. The specific heat capacity of water = 4.2 J g 1 K 1. energy =...kj [2] OR 2011

59 (ii) 9 alculate the amount, in moles, of N 4 SN used by the research chemist. amount =... mol [1] (iii) alculate the enthalpy change of reaction. Include the sign in your answer. Give your answer to two significant figures. Δ r =...kj mol 1 [3] PART (c) ONTINUES ON PAGE 10 OR 2011 Turn over

60 10 (c) Standard enthalpy changes of reaction can also be determined using average bond enthalpies. (i) What is meant by the term average bond enthalpy?... [2] Table 3.1 below shows some average bond enthalpies. bond average bond enthalpy / kj mol = +611 Table 3.1 (ii) Explain the bonding in a = double bond. Use the orbital overlap model.... [2] (iii) Suggest why the average bond enthalpy of a = bond is not twice the bond enthalpy of a bond.... [1] OR 2011

61 (iv) 11 Propane can be cracked to make ethene. + Using the average bond enthalpies in Table 3.1, calculate the enthalpy change of this reaction. Δ r =...kj mol 1 [2] (v) The actual value for the enthalpy change of this reaction is +81 kj mol 1. Suggest a reason why the actual value for the enthalpy change of this reaction is different from the calculated value.... [1] [Total: 16] OR 2011 Turn over

62 4 atalysts speed up the rate of a reaction without being consumed by the overall reaction. (a) hlorine radicals in the stratosphere act as a catalyst for ozone depletion. 12 (i) Research chemists have proposed possible reaction mechanisms for ozone depletion. The equations below represent part of such a mechanism. omplete the equations. l + O 3 + lo + + O 2 [2] (ii) Write an equation for the overall reaction in (i).... [1] (b) One of the catalysed reactions that takes place in a catalytic converter is shown below. 2O(g) + 2NO(g) N 2 (g) + 2O 2 (g) The catalyst used is platinum/rhodium attached to a ceramic surface. Outline the stages that take place in a catalytic converter to allow O to react with NO [4] OR 2011

63 13 (c) Explain, using an enthalpy profile diagram and a Boltzmann distribution, how the presence of a catalyst increases the rate of reaction. In your answer you should organise your answer and use the correct technical terms [7] OR 2011 Turn over

64 14 (d) Explain why many industrial manufacturing processes use catalysts. Include in your answer ideas about sustainability, economics and pollution control [4] [Total: 18] OR 2011

65 15 5 This question is about halogenated hydrocarbons. (a) alogenoalkanes undergo nucleophilic substitution reactions with ammonia to form amines. Amines contain the N 2 functional group. For example, 1-bromopropane reacts with ammonia to form propylamine, N Br + 2N N 2 + N 4 Br (i) Iodoethane is reacted with ammonia. Write an equation for this reaction.... [2] (ii) The first step in the mechanism of the reaction between Br and N 3 is shown below. It is incomplete Br 3 2 N omplete the mechanism. Include relevant dipoles, lone pairs, curly arrows and the missing product. [3] OR 2011 Turn over

66 (b) A student investigates the rate of hydrolysis of six halogenoalkanes. 16 The student mixes 5 cm 3 of ethanol with five drops of halogenoalkane. This mixture is warmed to 50 in a water bath. The student adds 5 cm 3 of aqueous silver nitrate, also heated to 50, to the halogenoalkane. The time taken for a precipitate to form is recorded in a results table. The student repeats the whole experiment at 60 instead of 50. time taken for a precipitate to form / s halogenoalkane at 50 at l Br I Br ( 3 ) 2 2 Br ( 3 ) 3 Br OR 2011 Describe and explain the factors that affect the rate of hydrolysis of halogenoalkanes. Include ideas about the halogen in the halogenoalkanes the groups attached to the carbon of the carbon halogen bond (the type of halogenoalkane) the temperature of the hydrolysis. In your answer you should link the evidence with your explanation

67 [7] (c) Poly(tetrafluoroethene), PTFE, and poly(chloroethene), PV, are halogenated plastics. (i) Write an equation, using displayed formulae, for the reaction to form PTFE from its monomer. [3] (ii) The combustion of waste polymers can be used for energy production. What problem is caused by disposing of PTFE and PV in this way?... [1] [Total: 16] OR 2011 Turn over

68 6 Mass spectrometry and infrared spectroscopy are used in analysis. 18 (a) The mass spectrum of compound Z is shown below relative abundance (%) m / z ompound Z has the molecular formula 3 6 O x. (i) Using the mass spectrum, deduce the value of x in 3 6 O x. Explain your answer.... [2] (ii) Suggest a possible structure for Z. (iii) Suggest the formula of an ion that gives rise to the peak at m/z = 29 in this spectrum.... [1] (b) A space probe has detected the presence of the element iron on the surface of the planet Mars. Outline how a mass spectrum would show the presence of iron [1] OR [1]

69 (c) The space probe also detected different isotopes of sulfur on Mars. 19 (i) Outline how the mass spectrum would show how many different isotopes of sulfur were present on Mars.... [1] (ii) The relative atomic mass of the sulfur found by the space probe was different from the relative atomic mass of sulfur on Earth. Suggest why.... [1] (d) An environmental chemist used infrared spectroscopy to monitor air pollution outside a petrol station. The infrared spectrum below was obtained from one of these pollutants transmittance (%) wavenumber / cm What evidence is there in the spectrum that the pollutant may be a hydrocarbon rather than an alcohol or a carbonyl compound? [1] OR 2011 Turn over

70 20 (e) The infrared spectrum of a drug is shown below transmittance (%) wavenumber / cm 1 Suggest, with reasons, possible functional group(s) present in the drug [2] [Total: 10] OR 2011

71 21 7 Biofuels such as bioethanol and biodiesel are increasingly being used as an alternative to fossil fuels to provide energy. (a) Describe, with the aid of an equation, how bioethanol is manufactured by fermentation [3] (b) Biodiesel is obtained from plant oils. The manufacture involves several stages, all of which have a high energy requirement. Biodiesel is often described as being carbon-neutral because: plants convert atmospheric carbon dioxide into carbon compounds on burning biodiesel this carbon dioxide is returned to the atmosphere. (i) onstruct an equation to show the complete combustion of biodiesel. Assume that the molecular formula of the biodiesel is O [2] (ii) Suggest why biodiesel is not completely carbon-neutral. OR [1] (c) Many scientists suggest that society should use more biofuels rather than fossil fuels to provide energy. Other scientists are worried that biofuels will need large areas of land to grow suitable crops. Suggest disadvantages or advantages, other than being carbon-neutral, of using more biofuels [3] Turn over

72 22 (d) Unsaturated compounds in plant oils can also be used to make margarine. Describe how [2] (e) Part of the structure of an unsaturated compound in plant oils is shown below: 2 2 = 2 2 (i) Draw the displayed formula of the Z isomer of this part of the structure. [1] (ii) Explain why this part of the structure can have an E and a Z isomer.... [2] [Total: 14] END OF QUESTION PAPER OR 2011

73 23 ADDITIONAL PAGE If additional space is required, you should use the lined pages below. The question number(s) must be clearly shown OR 2011

74 24 ADDITIONAL PAGE opyright Information OR is committed to seeking permission to reproduce all third-party content that it uses in its assessment materials. OR has attempted to identify and contact all copyright holders whose work is used in this paper. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced in the OR opyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download from our public website ( after the live examination series. If OR has unwittingly failed to correctly acknowledge or clear any third-party content in this assessment material, OR will be happy to correct its mistake at the earliest possible opportunity. For queries or further information please contact the opyright Team, First Floor, 9 ills Road, ambridge B2 1GE. OR is part of the ambridge Assessment Group; ambridge Assessment is the brand name of University of ambridge Local Examinations Syndicate (ULES), which is itself a department of the University of ambridge. OR 2011

75 ADVANED SUBSIDIARY GE EMISTRY A hains, Energy and Resources F322 *F * andidates answer on the question paper. OR Supplied Materials: Data Sheet for hemistry A (inserted) Other Materials Required: Scientific calculator Friday 27 May 2011 Afternoon Duration: 1 hour 45 minutes * F * INSTRUTIONS TO ANDIDATES The insert will be found in the centre of this document. Write your name, centre number and candidate number in the boxes above. Please write clearly and in capital letters. Use black ink. Pencil may be used for graphs and diagrams only. Read each question carefully. Make sure you know what you have to do before starting your answer. Write your answer to each question in the space provided. If additional space is required, you should use the lined pages at the end of this booklet. The question number(s) must be clearly shown. Answer all the questions. Do not write in the bar codes. INFORMATION FOR ANDIDATES The number of marks is given in brackets [ ] at the end of each question or part question. Where you see this icon you will be awarded marks for the quality of written communication in your answer. This means for example you should: ensure that text is legible and that spelling, punctuation and grammar are accurate so that meaning is clear; organise information clearly and coherently, using specialist vocabulary when appropriate. You may use a scientific calculator. A copy of the Data Sheet for hemistry A is provided as an insert with this question paper. You are advised to show all the steps in any calculations. The total number of marks for this paper is 100. This document consists of 24 pages. Any blank pages are indicated. OR 2011 [/500/7834] D (SJF5670/SW) 23208/6 OR is an exempt harity Turn over

76 2 Answer all the questions. 1 Many organisms use the aerobic respiration of glucose, 6 12 O 6, to release useful energy. (a) The overall equation for aerobic respiration is the same as for the complete combustion of 6 12 O 6. (i) Write the equation for the aerobic respiration of 6 12 O [1] (ii) Explain, in terms of bond breaking and bond forming, why this reaction is exothermic.... [2] (b) The table shows some enthalpy changes of combustion, Δ c. substance Δ c / kj mol 1 (s) (g) O 6 (s) 2801 (i) What is meant by the term enthalpy change of combustion, Δ c?... [2] OR 2011

77 (ii) 3 The enthalpy change of formation, Δ f, of glucose, 6 12 O 6, cannot be determined directly. The equation for this enthalpy change is shown below. 6(s) (g) + 3O 2 (g) 6 12 O 6 (s) Suggest why the enthalpy change of formation of 6 12 O 6 cannot be determined directly.... [1] (iii) Use the Δ c values in the table to calculate the enthalpy change of formation of 6 12 O 6. Δ f =... kj mol 1 [3] [Total: 9] OR 2011 Turn over

78 2 The alcohols are an example of an homologous series. The table shows the boiling points for the first four members of straight-chain alcohols. 4 alcohol structural formula boiling point / methanol 3 O 65 ethanol 3 2 O 78 propan-1-ol O 97 butan-1-ol O 118 (a) (i) What is the general formula of a member of the alcohol homologous series?... [1] (ii) Deduce the molecular formula of the alcohol that has 13 carbon atoms per molecule.... [1] (b) Alcohols contain the hydroxyl functional group. What is meant by the term functional group? [2] (c) (i) At room temperature and pressure, the first four members of the alcohol homologous series are liquids whereas the first four members of the alkanes homologous series are gases. Explain this difference.... [3] OR 2011

79 (ii) 5 Methylpropan-1-ol and butan-1-ol are structural isomers. Methylpropan-1-ol has a lower boiling point than butan-1-ol. Suggest why.... [2] (d) Alcohols, such as methanol, can be used as fuels. (i) Write equations for the complete and incomplete combustion of methanol. complete:... incomplete:... [2] (ii) Suggest what conditions might lead to incomplete combustion of methanol.... [1] (iii) In addition to its use as a fuel, methanol can be used as a solvent and as a petrol additive to improve combustion. State another large-scale use of methanol.... [1] (e) Butan-1-ol can be oxidised by heating under reflux with excess acidified potassium dichromate(vi). Write an equation for the reaction that takes place. Use [O] to represent the oxidising agent.... [2] OR 2011 Turn over

80 (f) Butan-1-ol is one of the structural isomers of 4 10 O. 6 (i) Write the name and draw the structure of the structural isomer of 4 10 O that is a tertiary alcohol. name: structure: [2] (ii) Draw the structure of the structural isomer of 4 10 O that can be oxidised to form butanone. [1] [Total: 18] OR 2011

81 7 3 Nitrogen monoxide is an atmospheric pollutant, formed inside car engines by the reaction between nitrogen and oxygen. This reaction is endothermic. N 2 (g) + O 2 (g) 2NO(g) Δ = +66 kj mol 1 (a) (i) Explain the meaning of the term endothermic.... [1] (ii) What is the value for the enthalpy change of formation of nitrogen monoxide? answer =... kj mol 1 [1] (b) (i) omplete the enthalpy profile diagram for the reaction between nitrogen and oxygen. On your diagram add the product label the activation energy as E a label the enthalpy change as Δ. enthalpy N 2 (g) + O 2 (g) reaction pathway [3] (ii) Explain the meaning of the term activation energy.... [1] OR 2011 Turn over

82 8 (c) A research chemist investigates the reaction between nitrogen and oxygen. She mixes nitrogen and oxygen gases in a sealed container. She then heats the container at a constant temperature for one day until the gases reach a dynamic equilibrium. (i) Explain, in terms of the rate of the forward reaction and the rate of the backward reaction, how the mixture of N 2 (g) and O 2 (g) reaches a dynamic equilibrium containing N 2 (g), O 2 (g) and NO(g).... [2] (ii) The research chemist repeats the experiment at the same temperature using the same initial amounts of N 2 (g) and O 2 (g). This time she carries out the experiment at a much higher pressure. Suggest why much less time is needed to reach dynamic equilibrium the composition of the equilibrium mixture is the same as in the first experiment.... [5] (iii) The reaction between nitrogen and oxygen in a car engine does not reach a dynamic equilibrium. Suggest why not.... [1] OR 2011