8/8/2019 F322 June 2010 Mark Scheme
1/23
GCE
Oxford Cambridge and RSA Examinations
Chains, Energy and Resources
Advanced Subsidiary GCE F322
Chemistry A
Mark Scheme for June 2010
8/8/2019 F322 June 2010 Mark Scheme
2/23
OCR (Oxford Cambridge and RSA) is a leading UK awarding body, providing a wide range ofqualifications to meet the needs of pupils of all ages and abilities. OCR qualifications includeAS/A Levels, Diplomas, GCSEs, OCR Nationals, Functional Skills, Key Skills, EntryLevel qualifications, NVQs and vocational qualifications in areas such as IT, business,languages, teaching/training, administration and secretarial skills.
It is also responsible for developing new specifications to meet national requirements and theneeds of students and teachers. OCR is a not-for-profit organisation; any surplus made isinvested back into the establishment to help towards the development of qualifications andsupport which keep pace with the changing needs of todays society.
This mark scheme is published as an aid to teachers and students, to indicate the requirementsof the examination. It shows the basis on which marks were awarded by Examiners. It does notindicate the details of the discussions which took place at an Examiners meeting before markingcommenced.
All Examiners are instructed that alternative correct answers and unexpected approaches in
candidates scripts must be given marks that fairly reflect the relevant knowledge and skillsdemonstrated.
Mark schemes should be read in conjunction with the published question papers and the Reporton the Examination.
OCR will not enter into any discussion or correspondence in connection with this mark scheme.
OCR 2010
Any enquiries about publications should be addressed to:
OCR PublicationsPO Box 5050AnnesleyNOTTINGHAMNG15 0DL
Telephone: 0870 770 6622Facsimile: 01223 552610E-mail: [email protected]
8/8/2019 F322 June 2010 Mark Scheme
3/23
F322 Mark Scheme June 2010
General advice to Assistant Examiners on the procedures to be used
YOU WILL BE REQUIRED TO UNDERTAKE 10 PRACTICE AND 10 STANDARDISATIONSCRIPTS BEFORE STARTING TO MARK LIVE SCRIPTS.
1 The schedule of dates for the marking of this paper is very important. It is vital that youmeet these requirements. If you experience problems then you must contact your TeamLeader (Supervisor) without delay.
2 An element of professional judgement is required in the marking of any written paper.Candidates often do not use the exact words which appear in the detailed sheets whichfollow. If the science is correct and also answers the question then the mark(s) shouldnormally be credited. If you are in doubt about the validity of any answer then consult yourTeam Leader (Supervisor) by phone, the messaging system within SCORIS or e-mail.
3 Correct answers to calculations always gain full credit even if no working is shown. (TheShow your working is to help candidates, who may then gain partial credit even if their
final answer is not correct.)
4 Some questions may have a Level of Response mark scheme. Any details about thesewill be in the Additional Guidance.
5 If an answer has been crossed out and no alternative answer has been written then markthe answer crossed out.
6 In addition to the award of 0 marks, there is a NR (No Response) option on SCORIS.
Award 0 marks
if there is any attempt that earns no credit (including copying out the question orsome crossed out working)
Award NR (No Response)
if there is nothing written at all in the answer spaceOR
if there is any comment which does not in any way relate to the question beingasked (e.g. cant do, dont know)OR
if there is any sort of mark which is not an attempt at the question (e.g. a dash, aquestion mark)
7 Abbreviations, annotations and conventions used in the detailed Mark Scheme.
/ = alternative and acceptable answers for the same marking pointnot = answers which are not worthy of creditreject = answers which are not worthy of creditignore = statements which are irrelevantallow = answers that can be accepted( ) = words which are not essential to gain credit __ = underlined words must be present in answer to score a markECF = error carried forward
AW = alternative wordingora = or reverse argument
1
8/8/2019 F322 June 2010 Mark Scheme
4/23
F322 Mark Scheme June 2010
2
8 Annotations: the following annotations are available on SCORIS.
= correct response = incorrect responsebod = benefit of the doubtnbod = benefit of the doubt not givenECF = error carried forward^ = information omittedI = ignoreR = reject
Highlighting is also available to highlight any particular points on the script.
The following questions should be annotated with ticks to showwhere marks have been awarded in the body of the text:2(c)(ii), 3(b)(i), 5(d), 6(b) and 7
9 The Comments boxThe comments box will be used by your PE to explain their marking of the practice scriptsfor your information. Please refer to these comments when checking your practice scripts.You should only type in the comments box yourself when you have an additional object ofthe type described in Appendix B of the Handbook for Assistant Examiners and SubjectMarkers.Please do not use the comments box for any other reason.Any questions or comments you have for your Team Leader should be communicated byphone, SCORIS messaging system or e-mail.
10 Please send a brief report on the performance of the candidates to your Team Leader
(Supervisor) by the end of the marking period. The Assistant Examiners Report Form(AERF) can be found on the Cambridge Assessment Support Portal. This should containnotes on particular strengths displayed, as well as common errors or weaknesses.Constructive criticisms of the question paper/mark scheme are also appreciated.
8/8/2019 F322 June 2010 Mark Scheme
5/23
F322 Mark Scheme
Question Expected Answers Marks Add1 a i Series having same functional group and a general formula
1 ALLOW same functioCH2ALLOW organic comgroup that differ in le
ii
More surface contact OR bigger molecules
More van der Waals forces
2 BOTH answers nee
ALLOW higher relatielectrons OR longer atomsIGNORE surface are
ALLOW stronger vaninduced dipolesVDW forces is not su
More intermolecular fDO NOT ALLOW brebreaking covalent boIGNORE reference tobonds
b i Pent-1-yne OR pent-2-yne 1 ALLOW pentyne
Look for answer in th
answer line takes pre
ii CnH2n 2 1 ALLOW CnH2(n 1)
3
8/8/2019 F322 June 2010 Mark Scheme
6/23
F322 Mark Scheme
Question Expected Answers Marks Add1 b iii Correct displayed formula 1
C C C
H
H
H
iv Correct skeletal formula of cyclic hydrocarbon with formulaC6H10
1 Examples of correct
c
Energy required to break bonds = (+) 2912
Energy released to make bonds = ()4148
Enthalpy of combustion = 1236
3 ALLOW full marks foout
ALLOW (2 415) +
ALLOW (4 805) +OR (4 805) + (2 4
ALLOW ECF for calcALLOW 2 marks for
4
8/8/2019 F322 June 2010 Mark Scheme
7/23
F322 Mark Scheme
Question Expected Answers Marks Add1 d i (Enthalpy change) when one mole of a compound
is made from its elements (in their standard states)
(Standard conditions are) 298 K and 100 kPa
3 IGNORE energy requALLOW (energy chasubstanceDO NOT ALLOW enproducts
ALLOW 1 atmosphe1.01 105 Nm2 / 100temperature in wordsIGNORE 1 mol dm3
ii From energy cycleEnthalpy change to get elements = (60) (2 286) / (+)
632
Enthalpy change from elements = 987 + (+227) / ()760
Enthalpy change = 128
3 ALLOW full marks fo
ALLOW ECF from er
ALLOWtwo marks f/ +1392
ALLOWone mark foe i 26.0 100
100.1
26.0%
2 First mark for 100.1 O26.0) at bottom of fra
ALLOWfull marks foout
ALLOW from two sigvalueALLOW 25.97 / 26%
NO ECF for this part expression
5
8/8/2019 F322 June 2010 Mark Scheme
8/23
F322 Mark Scheme
Question Expected Answers Marks Add1 e ii 1.56 104OR 15600 OR 15601 1 ALLOW calculator va
rounded value to a mfigures
iii 1.5 104OR 15000 1 ALLOW 1.50 104 e
iv 96.2 1 ALLOW ECF from (iALLOW calculator varounded value to a mALLOW 96.1476828
ALLOW any value bewas calculated by div
v Any two from:Low atom economy gives a poor sustainability OR low atomeconomy means lots of waste
A use for the aqueous calcium hydroxide needs to be
developed to increase atom economy
Alternative process needs to be developed with high atomeconomy
2 ANNOTATE WITH TIGNORE comments a
ALLOW ECF from (i)have good sustainab
ALLOW find a use foeconomy
Total 23
6
8/8/2019 F322 June 2010 Mark Scheme
9/23
F322 Mark Scheme
Question Expected Answers Marks Add2 a i Branched chain alkane of formula C5H12 to C9H20
e.g. 2-methylpentane, 3-methyloctane
1 Must have position nDO NOT ALLOW 1-metcDO NOT ALLOW inc2-methypentane etc
b i Vibrate(more) 1 ALLOW bend / stretcIGNORE rotateNOT break / molecul
ii Incomplete combustion 1 ALLOW not enough
iii NO for photochemical smog ORlow level ozone
CO is toxic
2 ALLOW NO can (everesult in respiratory irdepletes high level oIGNORE greenhouse
ALLOW poisonous OALLOW CO reducesoxygen
Oxygen combines wi
IGNORE CO is harm
c i Makes nitrogen AND carbon dioxide
2CO + 2NO N2 + 2CO2
2
ALLOW any correct
IGNORE state symbo
7
8/8/2019 F322 June 2010 Mark Scheme
10/23
F322 Mark Scheme
Question Expected Answers Marks Add2 c ii
One activation energy correctly labelled on enthalpy profilediagram
Idea that activation energy is lowered
Catalyst has a different reaction pathway OR differentreaction mechanism OR two curves drawn on profile
Correct diagram of reaction profile for exothermic reactionwith product below reactants with y axis as enthalpy orenergy and Hlabel arrow should go down. Ignore a
small gap between at either end ofHline
Drawing of Boltzmann distribution axes labelled number of
molecules and energy
More molecules with energy above activation energy with acatalyst
More effective collisions OR more successful collisions
7 ANNOTATE WITH TWith the line/arrow ncurve or reactant linefor activation energyALLOW vertical line
DO NOT ALLOW arr
Marks can be awardeor from Boltzmann
Boltzmann distributionot end up at 0 on y-
8
8/8/2019 F322 June 2010 Mark Scheme
11/23
F322 Mark Scheme
Question Expected Answers Marks Add2 d Any two benefits from:
Save crude oil OR no risk of large scale pollution fromexploitation of crude oil
Biodiesel is renewable OR diesel is non-renewable
Use of biodiesel is (more) carbon-neutral OR plants take upthe carbon dioxide released during combustion
and one disadvantage
Land not used to grow food crops OR (rain)forests have tobe cut down to provide land OR food prices may risebecause less is grown
3 ANNOTATE WITH T
ALLOW decrease th
ALLOW plants are anon-renewable resou
sustainable / diesel is
ALLOW lower carboIGNORE can be usewithout any conversi
IGNORE comments pesticides
Destroys habitats is n
Total 17
9
8/8/2019 F322 June 2010 Mark Scheme
12/23
F322 Mark Scheme
Question Expected Answers Marks Add3 a Answers clockwise from top left
CH3CH2CH2COOH
CH3CH2CHCH2
CH3COOCH2CH2CH2CH3
CH3CH2CH2CHO
4 ALLOW skeletal form
ALLOW butanoic aci
ALLOW but-1-ene
ALLOW butyl ethano
ALLOW butanal
If name and structure
If C3H7 used instead then apply ECF
If wrong carbon skele
then apply ECF
If a hydrogen is miss
10
8/8/2019 F322 June 2010 Mark Scheme
13/23
F322 Mark Scheme
Question Expected Answers Marks Add3 b i Nucleophilic substitution
Heterolytic
Dipole shown on CI bond, C+ and I
Curly arrow from OH to carbon atom of CI bond
Curly arrow from CI bond to the iodine atom
5 ANNOTATE WITH T
DO NOT ALLOW fis
No need to show loneCurly arrow must compair on the oxygen of
ALLOW SN1 mechan
dipole shown on CI
curly arrow from CI
curly arrow from OH
ii Use reflux OR heat for more than 20 minutes
CClstronger bond (than CI bond) OR CClshorter bond(than CI bond) OR CClbond is harder to break OR needsmore energy to break CClbond OR ora
2 ALLOW heat strong
a higher temperature
Answer must refer to
Total 11
11
8/8/2019 F322 June 2010 Mark Scheme
14/23
F322 Mark Scheme
Question Expected Answers Marks Add4 a i Any two from:
Any value between 10001300 Any value between 28503100 Any value between 32003550
2
ii Orange to green or blue 1
iii
CH3CH2OH + [O] CH3CHO + H2OORCH3CH2OH + 2[O] CH3COOH + H2OCorrect organic product Balanced equation
2 IGNORE any state sy
ALLOW CH3COH in
ALLOW equations wproduct mark
b i Absorption around 28503100 (cm1) so contains CHbonds
No otherimportant absorptions present / no other
characteristic absorptions
2 Answer must have a i.e. use of cm1 or da
Has no other peaks
is not sufficientBUTThere are no peaks dsufficient
ALLOW peaks insteaALLOW no absorptioabsorption due to car
ii Peak furthest to right hand side is 58 / molecular ion peak is58 / peak at highest mass
1 ALLOW peak at m/zspectrum / M peak ismolecular mass
DO NOT ALLOW highighest peak
12
8/8/2019 F322 June 2010 Mark Scheme
15/23
F322 Mark Scheme
Question Expected Answers Marks Add4 b iii
H C C C C H
H
H
H
H
H
H
H
H
H C C C H
H
H
H
CH3
H
HBOTH isomers correct
1 If three structures are
ALLOW skeletal form
IGNORE incorrect na
iv CH3+
C2H5+
C3H7+ / CH3CH2CH2
+ / (CH3)2CH+
3 Essentially marks arepositive ions Formula of two fragmBUTformulae of all three f
v CH3CH2CH2CH3 because there is a peak at m/z= 29 1 ALLOW name, displaALLOW butane beca
ALLOW butane becalisted in (iv)
Total 13
13
8/8/2019 F322 June 2010 Mark Scheme
16/23
F322 Mark Scheme
Question Expected Answers Marks Add5 a Sideways overlap of two p orbitals on each carbon atom
forms -orbital or-bond above and below plane ofmolecule
2 Answers can be awasee additional page wsee
Drawings with a doubmaximum of one mar
Drawing above with n
14
8/8/2019 F322 June 2010 Mark Scheme
17/23
F322 Mark Scheme
15
8/8/2019 F322 June 2010 Mark Scheme
18/23
F322 Mark Scheme
Question Expected Answers Marks Add5 b i Double bond does not rotate / restricted rotation of the
double bond
Each carbon atom of double bond is bonded to (two)different groups
2 ALLOW bond does
ALLOW each carbonto (two) different atom
bonded to different gii C and E 1
16
8/8/2019 F322 June 2010 Mark Scheme
19/23
F322 Mark Scheme
Question Expected Answers Marks Add5 c CH3CH2OH / ethanol 1 IGNORE alcohol
d
C4H8 + HBr C4H9Br
C2H4 + HBr C2H5Br
B makes CH3CH2CH2CH2Br CH3CHBrCH2CH3
QWC number of products is linked to structure of alkenee.g. because D is symmetrical ORB is not symmetrical
Movement of electron pair from double bond to attack
hydrogen of HBr and breaking of HBr bond
Correct dipole shown on HBr
Correct carbonium ion drawn
Curly arrow from Br to the carbonium ion
9 ANNOTATE WITH TQWC mark and 8 oth
The equation must be
of steps as in a mech
ALLOW skeletal or dALLOW B makes 1-bbutane if marks for
ALLOW curly arrow fbromide ion
ALLOW marks for thalkene is used e.g. foIf two mechanisms aD
17
8/8/2019 F322 June 2010 Mark Scheme
20/23
F322 Mark Scheme
Question Expected Answers Marks Add5 e i
C C C C
H
H
C2H5
H
H
H
C2H5
H
1 Must have at least twat the endAll carboncarbon boshownALLOW bond to ethy
IGNORE any bracke
ii Poly(but-1-ene) 1 ALLOW polybut-1-enn.b. the bracket is pa
DO NOT ALLOW po
f i (Lots of) OH group present
Can form hydrogen bonds with water
2 ALLOW hydroxyl groAlcohol group is not s
ii Any two from:Incineration to produce energy OR combustion to produceenergy
Sorting and recycling OR sorting and remoulding
Cracked (to give monomers) OR as an organic feedstock
2Used as a fuel is not
IGNORE use photodpolymers
Total 21
18
8/8/2019 F322 June 2010 Mark Scheme
21/23
F322 Mark Scheme
Question Expected Answers Marks Add6 a Low pressure because more (gas) molecules on right hand
side of equation OR low pressure because V= positive
Low temperature because the (forward) reaction isexothermic
2 ALLOW low pressureright hand side of eq
bIncreased pressure speeds up reaction / ora
900 oC increases the rate OR increased temperaturespeeds up reaction / ora
Idea that high enough temperature without compromisingyield OR idea that high enough pressure withoutcompromising yield
3 ANNOTATE WITH T
ALLOW pushes gas
c i 5.68 107 / 5.7 107 1 ALLOW two or moreCalculator answer is
ii Used to heat the incoming gases 1 ALLOW used to heanational grid
Provide energy to crebecause one conditio
Total 7
19
8/8/2019 F322 June 2010 Mark Scheme
22/23
F322 Mark Scheme
20
Question Expected Answers Marks Add7
InfraredQWC 1720 cm1 indicates carbonyl group
QWC broad 2900 cm1 indicates OH bond in carboxylicacid
QWC 1080 cm1 indicates CO bond
Percentage compositionMole ratio C : H : O = 2.23 : 2.22 : 4.44 Empirical formula is CHO2
(mass of one mole is 90 g) so Mr is 90
QWC molecular formula is C2H2O4 with working out fromMr
Structure is
COOH
COOH
8 ANNOTATE WITH T QWC Structureonce
ALLOW 1720 indicat
ketones, esters, carbALLOW 2900 indicat
ALLOW 1080 indicatacids
ALLOW 26.7/12.0. 2ALLOW COOHALLOWtwo marks f
no working out
ALLOW 0.0945/0.00
ALLOW
COOH
O
CHO
Total 8
8/8/2019 F322 June 2010 Mark Scheme
23/23
OCR (Oxford Cambridge and RSA Examinations)
1 Hills Road
Cambridge
CB1 2EU
OCR Customer Contact Centre
14 19 Qualifications (General)
Telephone: 01223 553998
Facsimile: 01223 552627
Email: [email protected]
www.ocr.org.uk
For staff training purposes and as part of our quality assurance
programme your call may be recorded or monitored
Oxford Cambridge and RSA Examinationsis a Company Limited by GuaranteeRegistered in EnglandRegistered Office; 1 Hills Road, Cambridge, CB1 2EURegistered Company Number: 3484466OCR is an exempt Charity
OCR (Oxford Cambridge and RSA Examinations)Head officeTelephone: 01223 552552F i il 01223 552553