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OCR~RECOGNISING ACHIEVEMENT

ADVANCED SUBSIDIARY GCECHEMISTRY

2812/01

Chains and RingsTHURSDAY 11 JANUARY 2007 Morning

Time: 1 hourAdditional materials: Scientific calculator

Data Sheet for Chemistry (Inserted)1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

CandidateName

CentreNumber I I I I I I CandidateNumber I I I I I!NSTRUCTIONS TO CANDIDATES 1 Write your name, Centre number and Candidate number in the boxes above. Answer all the questions. jI Use blue or black ink. Pencil may be used for graphs and diagrams only. Read each question carefully and make sure you know what you have to do before starting your answer. Do not write in the bar code. Do not write outside the box bordering each page. WRITE YOUR ANSWER TO EACH QUESTION IN THE SPACE PROVIDED. ANSWERS WRITTEN

ELSEWHERE WILL NOT BE MARKED.INFORMATION FOR CANDIDATES The number of marks for each question is given in brackets [ 1 at the end of FOR EXAMINER'S USEeach question or part question. You will be awarded marks for the quality of written communication where this Qu. Max. Markis indicated in the question. 1 You may use a scientific calculator. 12 A copy of the Data Sheet for Chemistry is provided as an insert with this 2 14question paper. You are advised to show all the steps in any calculations. 3 12

4 125 10

TOTALl 60

This document consists of 14 printed pages, 2 blank pages and a Data Sheet for Chemistry.

t _ g ~ : ~ ~ ~ C _ ~ ~ )2 l_42_4_ /2 _O_C_R_2007 [T il 0013424) OCR is an exempt Charity [TUrnOVe~

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1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1

3Answer all the questions.

" ! Crude oil is first separated by fractional distillation. The fractions can then be refined further bycracking, reforming and isomerisation.The reaction sequence below shows the production of heptane, C7H16, from fractional distillationof crude oil. followed by cracking, reforming and isomerisation.

cracking .----__... propene + A/~

//"heptane:_ reforming- ,fractionaldistillation methylcyclohexane + Brude oil '" isomerisation --- .. branched alkanes

(a) What is meant by the term fractional disti!!ation?

. .. .. .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. ... .. .. .. .. .. .. .. .. .. .. .. .. ... [ 1](b) The cracking of heptane produces propene and A.

Write a balanced equation for this cracking of heptane ..................................... [1]

(c) The reforming of heptane produces methylcyclohexane and B.(i) Show the structural formula of methylcyclohexane.

[1](ii) Write a balanced equation for this reforming.

[1]OCR 2007

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IJ

5(iii) Predict which of 2-methylhexane, 2,3-dimethylpentane and 2,2,3-trimethylbutane has the

lowest boiling point........................................................................................................................................ (1 ]

(iv) Explain why 2-methylhexane, 2,3-dimethylpentane and 2,2,3-trimethylbutane havedifferent boiling points .

......................................................................................................................... ", [2](e) Crude oil and its fractions are described as non-renewable fossil fuels, To reduce the demand

for fossil fuels, ethanol can be mixed with petrol. Ethanol is an example of a renewablebiofuel,(i) What is meant by a biofuel?

..... .......... .......... ......... .......... .......... .......... ......... .......... .......... ......... .......... .......... .......... ... ( 1](ll) Why are fossil fuels non-renewable but ethanol renewable?

... .......... .......... ......... .......... .......... ......... .......... .......... .......... ......... .......... .......... ......... ...... [ 1][Total: 12]

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62 This question is about two alcohols, ethanol and propan-z-ol, CH3CH(OH)CH3.

{a) Ethanol can be formed by fermentation of glucose, C6H1206.(i ) Write a balanced equation, including state symbols, for the formation of ethanol by

fermentation ....... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ... [ 2]

(ii) Fermentation only occurs. in the presence of yeast. State two other essential conditions .

....................................................................................................................................... [2](iii) How would you know when fermentation of glucose is complete?

..... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... .... [ 1](b) Propan-z-ol can be formed by the hydration of an alkene in the presence of a catalyst.

(i ) Suggest a suitable catalyst for this reaction ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... .... [ 1]

(ii) This is an electrophilic addition reaction. What is meant by the term e/ectrophi/e?....................................................................................................................................... [1]

(c) A mechanism for the reaction in (b) is shown below.CH3 H CH3 H- . / I IC=C -- H-C-C-H -/ \ step 1 + I step 2H H H

0 -:0'0 + / - , 0 +H H

CH3 HI IH-C-C-H - H-C-C-HI 1 step 3 I I''0 H :0'.. H/+~ /H H H

CH3 HI I

(i) Add 'curly arrows' to the mechanism to show the movement of electron pairs in steps 1, 2a~3. ~

(ii) Suggest, with a reason, the role of the H+....... ...... ...... ...... ...... ....... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... ...... .. [ 1]

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7(0) Propan-2-ol is flammable and readily burns.

Write a balanced equation for the complete combustion of propan-z-ol................................................................................................................................................ [2]

(e) Compound 0, shown below, can be used as a solvent for plastics and fats and is also used inperfumery.

//0H3C-C CH3' " /-CH

""CH3compound 0

Compound 0 can be prepared from propan-z-ol and another organic compound. Identify thisother compound.

[1 ][Total: 14]

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9:3 Methyl allyl chloride, MAC, is an important industrial chemical. It is used as an intermediate in the

production of synthetic fibres, pharmaceuticals and epoxy resins. The structural formula of MAC isshown below.

MAC(a) Give the systematic chemical name of MAC.

, [1](b) MAC contains the alkene group and can undergo polymerisation. Draw a section of the

polymer, poly(MAC), showing two repeat units.

[2]

Part (c) continues on the next page

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10MAC reacts with NaOH to produce compound E.

compound E

The reaction scheme below shows how compound E can be converted into a variety of otherchemicals.

compound Gompound F

H2/Ni catalyst

compound EH CH3\ /C=C/ \H CH20H

compound IH CH3\ /C=C/ \H COOH

compound HH CH3I IH-C-C-CH BrI I 2H Br

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11(l) Draw the structures of compounds F and G in the boxes. [2]

(ii) Complete the balanced equation for the formation of compound H.compound E compound H

H CH3I I----I~ H-C-C-CH BrI I 2

H Br

+ ..

[2]{Hi) State the reagents and conditions for the formation of compound I.

....................................................................................................................................... [2](lv) Suggest a possible organic intermediate that could be formed in the formation ofcompound I.

[1 ](d) Explain how infra-red spectroscopy could be used to distinguish between compound E andcompound I.

............................................................................................................................................... [2][Total: 12]

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12~l Butane, C4H10, under certain conditions, reacts with Cl2 to form a mixture of chlorinated products.One possible product is C4HgCl.

(a) (l) State the conditions ........................................................................................................................................ [1]

(ii) Write equations to show the mechanism of this reaction.initiation .propagation ........................................................................................................................................ [3]

(iii) Write one equation for a reaction that would terminate this mechanism ........................................................................................................................................ [1]

(Iv) State the type of bond fission involved in the initiation step. .. [1](b) One other possible product of the reaction between butane and chlorine is compound J,

C 4HSC l2 ' shown below.compound J

H Cl H HI I I IH-C-C-C-C-HI I I IH H Cl H(i) Name compound J .

....................................................................................................................................... [1](ii) Draw the skeletal formula of compound J.

[1 ](iii) In addition to compound J, suggest one other possible structural isomer of C4HsCl2 thatcould have been formed in this reaction.

[1]

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t J l

13(c) 1-Chlorobutane can react with a solution of sodium hydroxide to produce but-1-ene, as shown

in the equation below.

(i ) State the solvent in which the sodium hydroxide is dissolved ............ [1]

(ii) State the type of reaction ........................................................................................................................................ [1]

(iii) Compound J also reacts with sodium hydroxide to produce a mixture of structuralisomers, each with the formula C4H6.Draw one of the structural isomers formed.

[1][Total: 12]

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145 In this question, one mark is available for the quality of use and organisation of scientific terms.

" Describe, with the aid of a suitable diagram, the formation of the n-bond in propene. State the shape, and an approximate value for the bond angles, around each carbon atom in

propene... Describe, with the aid of a suitable example, why some alkenes show cis-trans isomerism .

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............................................................................................ ,: [9]Quality of Written Communication [1]