OCR J640, J645 User Manual

Mark Schemes for the Units

June 2007

Oxford Cambridge and RSA Examinations

Gateway Science Suite J640 - J645

GCSE

J640-5/MS/R/07

OCR (Oxford, Cambridge and RSA Examinations) is a unitary awarding body, established by the University of Cambridge Local Examinations Syndicate and the RSA Examinations Board in January 1998. OCR provides a full range of GCSE, A level, GNVQ, Key Skills and other qualifications for schools and colleges in the United Kingdom, including those previously provided by MEG and OCEAC. It is also responsible for developing new syllabuses to meet national requirements and the needs of students and teachers.

This mark scheme is published as an aid to teachers and students, to indicate the requirements of the examination. It shows the basis on which marks were awarded by Examiners. It does not indicate the details of the discussions which took place at an Examiners’ meeting before marking commenced.

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 skills demonstrated.

Mark schemes should be read in conjunction with the published question papers and the Report on the Examination.

OCR will not enter into any discussion or correspondence in connection with this mark scheme.

Any enquiries about publications should be addressed to:

OCR Publications PO Box 5050 Annesley NOTTINGHAM NG15 0DL

Telephone: 0870 870 6622 Facsimile: 0870 870 6621 E-mail: publications@ocr.org.uk

CONTENTS

GCSE Science

MARK SCHEMES FOR THE UNITS

Unit Content Page

B621/01 Science B: Unit 1 Modules B1,

C1, P1 Foundation

B621/02 Science B: Unit 1 Modules B1,

C1, P1 Higher

B622/01 Science B: Unit 2 Modules B2,

C2, P2 Foundation

B622/02 Science B: Unit 2 Modules B2,

C2, P2 Higher

B623/01 Additional Science B: Unit 1

Modules B3, C3, P3 Foundation

B623/02 Additional Science B: Unit 1

Modules B3, C3, P3 Higher

B631/01 Biology B: Unit1 Modules B1,

B2, B3 Foundation

B631/02 Biology B: Unit1 Modules B1,

B2, B3 Higher

B641/01 Chemistry B: Unit 1 Modules C1,

C2, C3 Foundation

B641/02 Chemistry B: Unit 1 Modules C1,

C2, C3 Higher

B651/01 Physics B: Unit1 Modules P1,

P2, P3 Foundation

B651/02 Physics B: Unit1 Modules P1,

P2, P3 Higher

* Grade Thresholds 136

1

15

29

39

51

59

67

79

89

101

115

127

Mark Scheme B621/01

June 2007

Abbreviations, annotations and conventions used in the detailed Mark Scheme.

/ = alternative and acceptable answers for the same marking point

(1) = separates marking points not = answers which are not worthy of credit reject = answers which are not worthy of credit ignore = statements which are irrelevant allow = answers that can be accepted

( ) = words which are not essential to gain credit __ = underlined words must be present in answer to score a mark ecf = error carried forward AW = alternative wording ora = or reverse argument

1

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

1 a

b i

ii

c any one from

Total 5

bread (1) 1 more than one response on the line scores zero

orange juice (1) 1 allow orange or juice

bread (1) 1 more than one response on the line scores zero

(high in) protein (1) because they are growing/for repair (1)

(high in) iron (1) to prevent anaemia/reference to menstruation/reference to blood (1)

and

second mark for correct link between protein or iron with its role

if no answer on the line accept ringed, underlined or ticked word or indicated on diagram etc

more than one response on the line scores zero

if no answer on the line accept ringed, underlined or ticked word or indicated on diagram etc

2 one mark for either protein or iron or role

second mark is for correct role of iron or protein

ignore strong/healthy NOT white blood cells

eg ‘protein and iron for growth’- 2 marks ‘protein for growth’ – 2 marks ‘iron for growth’ – 1mark

2

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

2 a

b i

ii

iii

D long sighted/far sighted/colour blind/colour

deficiency/glaucoma/cataracts/ tunnel vision(1)

G cornea (1)

iris (1)

G lens (1)

C the idea of a different shape/the idea of

focusing light (1)

Total 5

1 allow astigmatism

NOT 'blindness', double vision ignore conjunctivitis

2 more than one response on the line scores zero

1 more than one response on the line scores zero

1 allow converse answers

ignore incorrect eye part, refraction NOT reflection

3

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

3 a

b

c i

ii

d i

pregnancy/ovulation (1) 1 allow heavy periods, prevent egg release, babies, period pains,

fertilisation

ignore references to disease

do not have to remember to take it every day/pill difficult to swallow/less likely to cause problems if you are sick (1)

ovary/ ovaries (1)

breasts (development)/hips widen/ periods (start)/menstrual cycle/ pubic hair/hair under arms/body hair (1)

to test it/to see if it is safe/to see if it works (1) 1

1 allow ‘ a patch lasts for a week’

‘it lasts longer than a pill’ ‘more convenient than taking a pill everyday’ ‘you might forget to take the pill’ ‘do not have to take lots of pills’ ‘easier to use than swallowing a pill’ ‘easier to put on a patch than swallow a pill’

NOT ‘it is much easier’

‘more convenient’

1 more than one response on the line scores zero

1 ignore makes hair grow (must be body hair)

ignore hips larger ignore egg release/references to ovulation/specific references to

changes in the uterus

ignore moods and spots

ii

Total 6

idea of cruelty / ethical objection (1)

may work differently in different species/animals are not the same as humans(1)

1 allow it could harm/hurt/kill animals/inhumane

allow references to animal rights

eg animal can’t speak for itself eg some people think animals have same rights as humans eg animals have no control over what happens to them

eg it might not hurt the animal but could harm the human

4

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

4 a

b

c

Total 4

distorts what is seen and heard (1) 1 more than one box ticked scores zero

idea that they may be harmful/the idea that the use can be controlled or monitored (1)

some are more harmful/addictive than others (1)

different laws apply to each group (1)

1 allow ‘because they are dangerous’

‘they may be addictive’ ‘not everyone can get them’ ‘you only get the amount you need’ ‘to prevent overdose’ ‘to prevent misuse’

ignore ‘you may mistreat the drugs’

2 references to classes of drugs must be correct for first mark eg class

A are more dangerous than class C eg depends how dangerous they are eg put into different classes according to their effect/side effects/long & short term effects eg heroin is more dangerous than cannabis

ignore Class A are stronger/worse than Class C ignore incorrect references to class of drugs when related to

penalties eg class C drugs attract a higher prison sentence than class A scores 1 eg class A drugs get prison sentence, but class C are legal scores 0 eg the more dangerous the drug (1) the heavier the penalty (1)

5

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

5 a

b

c

Total 4

25 (1)

propanol (1)

largest (temperature) rise/change (1)

energy or heat given out (1) 1 allow temperature increase

1 correct response only

2

carry error forward

if response for a) is greater than 30, do not credit propanol if response for a) is greater than 30, paraffin gets 1 mark

independent of first part

allow ‘ it starts at the lowest and ends at the highest temperature’ allow it rises more allow because it went from 15 to 45 which is the highest

ignore ‘highest temperature at end’

‘it went up by 30 ‘it starts at 15 and goes up to 45’

allow heat or energy produced/made/exits/released ignore gives more energy

eg energy/heat is lost (1) (limit of acceptability)

NOT energy/heat is created

0

’

6

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

6 a any two from

microwave/conventional oven/boiling/steaming/

grilling/barbecue /bbq(1)

b i

ii

Total 4

change in colour/change in texture (1) 1 allow 'it goes white'

new substance formed/difficult to reverse (1) 1 allow energy change takes place

2 allow scramble/poach/baking/coddling

ignore omelette

‘it goes solid’ ‘runny to hard’ ‘the yolk goes more orangey’

ignore ref to shape changes eg ‘ it spreads out in the pan’

allow colour change allow higher level answers involving changes to molecules, eg molecules in egg change shape (ignore references to particles)

ignore references to change of state

7

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

7 a

b i

ii

c

(catalytic) cracking (1) 1 allow decomposition

petrol (1) 1 more than one response on the line scores zero

ethene (1) 1 allow spelling errors, eg ethane

used as a catalyst/speeds up reaction (1) 1 allow higher level answers such as lower activation energy

Total 4

if no answer on the line accept ringed, underlined or ticked word etc

allow C

H H

2H4,

\ / C = C / \ H H mark what is on answer line first- only look at list if no answer on line

allow answer circled/underlined in list

‘it speeds up the experiment’

NOT enzyme

‘speeds up heating’ ‘it won’t take as long to start the reaction’

8

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 8 a

b

c

NaHCO

Ca(OH)

H H

1 allow badly copied formula eg ‘NAHCO

3

1 allow badly copied formula eg Ca(OH)

2

l l H ─ C ─ C ─ H l l H H

Total 3

NOT ‘calcium hydroxide’ in words

1 allow C

allow badly copied structure but it must have only 2 C’s and 6H’s

NOT HHHHHHCC

2H6

’ or NaHCo3’ etc

3

2

/Ca(OH)2

9

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

9 a

b

2 3 correct scores 2

polythene

polystyrene

nylon

will not decay or decompose (by bacterial action) (1)

clothing

packaging

plastic bags

1 or 2 correct scores 1

1 allow 'does not rot'/‘will not break down’

ignore

‘does not disintegrate/deteriorate/wear away’ ‘burning’ ‘recycling’

10

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

c property

idea of poor conductor (of electricity)/idea of good (electrical) insulator (1)

flexible or bendy (1)

easy to mould (1)

easy to colour (1)

idea of waterproof/insoluble in water (1)

non toxic (1)

Total 5

explanation

so that you do not get a shock or electrocution or idea of protection (from electrocution) (1)

so that it can bend around corners/AW (1)

so wires can be identified (1)

to keep water away from (copper) wires/prevent electrocution (1)

reason needs to be linked to health and safety eg idea of safe handling (1)

2

any two properties can score or one property and correct explanation for two marks

explanation mark is conditional on correct property ignore tough/lightweight/non biodegradable/cheap/elastic/

durable/heat insulator/any reference to melting point/does not corrode/easy to store

11

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 10 a

b i

ii

c

d

Total 7

hot cold 9

9 9

9 (9)

jacket on water tank/oven gloves (1) 1 allow single word if it is clear what is meant

steel radiator (1) 1 ignore correct answers not from list

idea that ice is melting/ice is at melting point/ ice is at its freezing point (1)

(the amount of heat or energy needed to) raise/change the temperature by 1K/°C (1) of 1 g/1 kg (1)

2 one correct 1 mark

all correct 2 marks

do not credit tick for burning match (bottom tick)

if two answers are given, both must be correct for mark

ignore wooden handle or other correct answers not from list

1 allow defrosting, thawing

eg they are defrosting

NOT they have defrosted or thawed NOT ice has melted

ignore unfreezing NOT peas melting/ peas at melting point/it is melting/ they are

melting etc

2

12

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 11 a i

ii

b i any two from

ii

c

d any two from

Total 8

D (1) 1 correct letter only

B (1) 1 correct letter only

idea that light travels (very) quickly/quicker(1)

light can be seen a long way off (1)

idea that no need for a person to take the message/fires/beacons/flashing lights could be used (1)

morse (1) 1 allow digital

microwave (1) 1 more than one response on the line scores zero

idea that foil reflects radiation/heat/ir (1) back into potato (1) keeps potato hot/insulates (1)

2 read whole response and look for both marking points

allow ‘it is quick’ NOT ‘light travels a long way’

allow ‘no-one has to travel’

if no answer on the line accept ringed, underlined or ticked word etc

2 ignore refs to Al as a conductor

allow ‘bounce’ for reflection mark

‘keeps heat in’

allow ‘foil traps air’- 1mark

‘foil traps air and air is a good insulator’ – 2 marks

13

B621/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 12 a i

ii

b

Total 5

idea that it causes damage/casualties (1) 1 allow earth shakes/ vibrates/cracks

seismometer (1) 1 more than one response on the line scores zero

feature p-waves s-waves

speed

travel through solids (only) (1)

type longitudinal(1) transverse(1)

tsunami, tidal waves, plates shake

ignore plates move, earth moves, volcanic activity

3 ignore references to primary and secondary

ignore descriptions of longitudinal and transverse waves

14

Mark Scheme B621/02

June 2007

Abbreviations, annotations and conventions used in the detailed Mark Scheme.

/ = alternative and acceptable answers for the same marking point

(1) = separates marking points not = answers which are not worthy of credit reject = answers which are not worthy of credit ignore = statements which are irrelevant allow = answers that can be accepted

( ) = words which are not essential to gain credit __ = underlined words must be present in answer to score a mark ecf = error carried forward AW = alternative wording ora = or reverse argument

15

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

1 a i

b

c

d

Total 5

bend/refract/focus (the light entering the eye) (1)

change the size of the pupil/control the amount of light entering the eye/ensure that the correct amount of light

ii

reaches the retina (1)

focused image lands on retina/focus on distant objects/aw (1)

laser surgery (1) 1 allow cornea surgery/conductive chiroplasty

(colour blindness is) inherited or genetic/lack of specialised cells in retina(1)

2 NOT reflects light/diffracts light

NOT control light going into the eye ignore idea of protection

allow prevent damage to the retina (caused by too much

light)/protects retina

allow let in more light in dim conditions/ aw allow to see in the dark (limit of acceptability)

1 allow the lens does not focus the light accurately

eg to focus the light into the correct position eg to see things far away

allow (lens) is the wrong shape, eg lens is too thick allow because the lens cannot accommodate NOT lens is concave or too thin or too long allow (lens) needs to be less powerful/thinner ignore lens is not working properly

NOT references to glasses or contact lenses

1 allow abnormal cones/lack of cones

allow wrong amount of cones ignore retina is damaged/abnormal retina allow some receptor cells in the retina do not work

16

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

2 a i

ii b

c

Total 5

breast (development)/hips widen/ periods (start)/menstrual cycle/ pubic hair/hair under arms/body hair (1)

progesterone (1) 1 be lenient on spelling eg allow progesterogen / progestogen

mimic pregnancy/aw (1) prevent ovulation/aw (1)

idea of cruelty / ethical objection /

may work differently in different species/animals are not the same as humans(1)

1 ignore makes hair grow (must be body hair)

ignore hips larger ignore eggs released/references to ovulation/specific references

to changes in the uterus

ignore moods and spots

2

1 allow it could harm/hurt/kill animals/inhumane

eg body thinks it is pregnant eg no egg produced

allow a reason and an explanation eg prevents ovulation or no

egg (1) to be fertilised (1)

ignore references to barriers to sperm

allow references to animal rights

eg animal can’t speak for itself eg some people think animals have same rights as humans eg animals have no control over what happens to them

eg it might not hurt the animal but could harm the human

17

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

3 a

b

c

d

Total 5

a systolic pressure of 120 and a diastolic pressure of 80 (1)

there does not appear to be any relationship/aw(1) 1 allow it does not matter/nothing

the higher the weight the higher the blood pressure/diastolic (1)

low blood pressure: dizziness/fainting/poor

circulation/ kidney failure (1)

high blood pressure: burst blood vessels/damage to

brain/kidney damage/heart disease/stroke(1)

1 tick in third box down

if more than one box is ticked = 0

allow circled, underlined or crossed answers

eg whatever the height the blood pressure is around 55 eg all different at different heights (limit of acceptability)

1 allow systolic

eg there is a positive correlation eg they are directly proportional eg when one goes up the other goes up eg there is an exponential increase

2 eg not enough blood reaches organs

allow coma, unconscious, cold hands/feet ignore tiredness and/or weakness

allow heart attacks or heart disorders allow higher level answers eg aneurysm/heart or cerebral

infarction

18

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

4 a

b

c

Total 5

LSD (1) 1 allow tick or circle on picture, if line blank

some are more harmful/addictive than others (1)

different laws apply to each group (1)

any mention of synapses (1)

slow down/reduce/block the neurotransmitter/ acetylcholine/ACh release (1)

less nerve impulses or signals travel to brain (1)

block the receptor sites/detection of the neurotransmitter acetylcholine/ACh (1)

2 references to classes of drugs must be correct for first mark eg

class A are more dangerous than class C eg depends how dangerous they are eg put into different classes according to their effect/side effects/long & short term effects eg heroin is more dangerous than cannabis

ignore Class A are stronger/worse than Class C ignore incorrect references to class of drugs when related to

penalties, eg Class C drugs attract a higher prison sentence than Class A scores 1 eg Class A drugs get prison sentence, but Class C are legal scores 0 eg the more dangerous the drug (1) the heavier the penalty (1)

2

eg prevents signals from the body getting to the brain

eg they block the chemical acetylcholine (1) so less nerve impulses travel to the brain (1) eg reduce the amount of chemical transmitter released (1) at synapses (1) making for slower reactions

ignore references to slower reactions or slowing down brain or

nervous system

ignore references to feeling depressed or ‘down’ allow any other named neurotransmitter

19

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

5 a i

ii

b

Total 5

energy or heat given out (1) 1 allow temperature increase

8400J scores (2)

BUT

energy = mass (of water) x SHC x temp change/ 100 x 4.2 x 20 (1)

endothermic/energy taken in or absorbed (1) given out/released (1)

allow heat or energy produced/made/exits/released ignore gives more energy

eg energy/heat is lost (1) (limit of acceptability)

NOT energy/heat is created

2 126 scores (1) MAX

2

allow heat or energy produced/made/exits/released NOT energy is created allow energy is ‘lost’(1) (limit of acceptability)

20

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

6 a

b any two from

c any two from

Total 5

new substance formed/difficult to reverse (1) 1 allow energy change takes place

(high temperature) kills microbes/bacteria/microorganisms/viruses/fungi/mould (1)

improve the texture (1)

improve the taste/flavour (1)

easier to digest (1)

shape of protein molecule changes (1)

process is irreversible/aw (1)

(process is called) denaturing/protein is denatured (1)

allow colour change allow higher level answers involving changes to molecules, eg molecules in egg change shape (ignore references to particles)

ignore references to change of state

2 allow get rid of bacteria

allow prevents food poisoning or named example eg salmonella ignore germs ignore protects from bacteria

ignore make it edible

ignore easier to eat allow some foods are poisonous if not cooked, eg red kidney

beans

2 allow protein molecule breaks down

allow protein molecule unfurls ignore protein molecule expands

eg molecule changes shape (1) and stays like that (1)

21

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

7 a i

gas oil

(1) 1

ii any two from

converts fraction where supply exceeds demand (into petrol) /aw (1)

identify fraction where supply exceeds demand i.e. naphtha or paraffin or fuel oil (1)

by cracking/large molecules broken into smaller molecules (1)

alkenes are also produced (1)

b

ethene (1) 1 allow spelling errors, eg ethane

Total 4

2 ignore references to mixing other fractions with petrol

allow C

H H

2H4

\ / C = C / \ H H mark what is on answer line first- only look at list if no answer on line

allow answer circled/underlined in list

22

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

8 a

Ca(OH)

1 allow badly copied formula eg Ca(OH)

2

/Ca(OH)2

NOT ‘calcium hydroxide’ in words

b

H H \ / C = C / \ H H

1 allow C

be careful not to confuse with chloroethene: H H \ / C = C

2H4

/ \

H Cl

Total 2

23

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

9 a

property

idea of poor conductor (of electricity)/idea of good (electrical) insulator (1)

flexible or bendy (1)

easy to mould (1)

easy to colour (1)

idea of waterproof/insoluble in water (1)

non toxic (1)

explanation

so that you do not get a shock or electrocution or idea of protection (from electrocution) (1)

so that it can bend around corners/AW (1)

so wires can be identified (1)

to keep water away from (copper) wires/prevent electrocution (1)

reason needs to be linked to health and safety eg idea of safe handling (1)

2

any two properties can score or one property and correct explanation for two marks

explanation mark is conditional on correct property ignore tough/lightweight/non biodegradable/ cheap/elastic/

durable/heat insulator/any reference to melting point/does not corrode/easy to store

24

B621/02 Final Mark Scheme June 2007

b landfill sites

any one from

unsightly/eyesore/smelly/causes litter/attracts vermin (1)

plastics are non-biodegradable/do not rot/do not decompose/do not decay/not attacked by bacteria/do not break down (1)

wastes (valuable) land/fills up quickly/destroys habitats (1)

wastes a valuable resource (1)

burning waste plastics any one from

makes toxic/poisonous gases or fumes(1)

wastes a valuable resource (1)

makes carbon dioxide (1)

makes carbon monoxide (1)

makes greenhouse gases (1)

leads to global warming (1)

Total 4

2 allow idea of makes a mess (limit of acceptability)

allow takes a long time to rot/does not break down easily ignore do not disintegrate/do not deteriorate

ignore pollution ignore references to harming animals

NOT dangerous/harmful gases or fumes allow makes carbon emissions ignore references to sulphur dioxide

ignore pollution unless qualified, eg pollution by toxic gases

25

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 10 a

b

c Total 5

idea of ice melting (1)

idea that energy is needed to change ice to water/AW (1)

(the amount of heat or energy needed to) raise/change the temperature by 1K/°C (1) of 1 g/1 kg (1)

A (1) 1

2 allow defrosting/thawing/solid melting/solid changes to

liquid/change of state

allow higher level answers

eg energy is used to break (intermolecular) forces or bonds eg ice is absorbing latent heat

allow bonds break between ice particles (limit of acceptability) beware of contradictions eg breaking intramolecular bonds or

forces

2

26

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 11 a

b i

morse (1) 1 allow digital

14

5 x 10 BUT 3 x 10 6 x 10

scores 3

8

scores 2

-7

or frequency = speed

/ wavelength speed = frequency x wavelength (1)

ii

crests line up with crests or troughs line up with troughs/AW (1) all waves have the same wavelength or frequency (1)

Total 6

3 5

14

on its own scores 0

allow abbreviations υ = fλ, c = fλ, s = fλ

2 both marks can be awarded from a diagram

eg

scores 2 (could be a square wave/digital wave)

scores 1 for same wavelength

27

B621/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 12 a

b Total 4

13 a any two from

b i

ii

Total 5

feature p-waves s-waves

speed

travel through

type longitudinal

cfc /chlorofluorocarbons (1) 1 ignore gases from aerosols or fridges

infrared cooks/heats/absorbed by surface(1)

increasing the kinetic energy of the particles(1)

passes to centre of food by conduction and/or convection (1)

(reduces) radiation/heat reflected (1) 1 ignore references to incorrect direction of reflection

(reduces) conduction and/or convection (1)

no (air) particles present (1)

solids (only) (1)

transverse (1)

(1)

3 ignore references to primary and secondary

ignore descriptions of longitudinal and transverse waves

2 ignore infrared bounces off surface

NOT infrared penetrates surface ignore references to heating top 1cm or top few centimetres

allow correct description of conduction or convection

eg infrared causes particles on the surface to vibrate (1) causing the rest of the particles to vibrate (1) which heats up the food in the centre eg infrared causes particles on the surface to vibrate more scores 2

ignore reflects light ignore bounces heat

2 NOT references to heat particles

28

Mark Scheme B622/01

June 2007

Abbreviations, annotations and conventions used in the detailed Mark Scheme.

/ = alternative and acceptable answers for the same marking point

(1) = separates marking points not = answers which are not worthy of credit reject = answers which are not worthy of credit ignore = statements which are irrelevant allow = answers that can be accepted

( ) = words which are not essential to gain credit __ = underlined words must be present in answer to score a mark ecf = error carried forward AW = alternative wording ora = or reverse argument

29

B622/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

1 a

b

c

d i ii

vertebrates (1) 1 allow any other way of indicating answer eg a tick

3 one for each correct line

all the animals

community

Orca

habitat

the fjord

predator

herring

prey

number of herring

no food/no herring to eat/no prey (1) 1 allow need to get more food/not enough food

built for speed (1) 1

eyes at side (of head)/live in (large) groups/camouflage (1)

Total 7

if two answers shown the answer in a circle should be marked

two lines from any box = 0 for that box

beware of marking the line already given in the question

allow other ways of indicating the linking eg pairing up labelled

boxes

ignore just no herring - must mention the idea of food ignore references to hunting

1 allow shoals/herd/flock to represent a group of fish

allow can hide easily/same colour as sea ignore can hide in (small) spaces

ignore darting around/reference to movement

30

B622/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

2 a

b i

ii

Asia/Latin America (1) 1 allow Latin

carbon dioxide/sulphur dioxide/carbon monoxide (1) 1 allow water/steam/nitrogen dioxide/nitric oxide/oxides of nitrogen

resources/water (1)

3

waste (1) sewerage (1) (either order)

Total 5

3 a

b

c i

ii

fur/hair (1) 1 allow (external) ears

lives in unexplored area/habitat difficult to access (1) 1 allow 'scientists haven't been there'/few people visit there/jungle

close to extinction/not many left (1) 1 allow will soon be gone/soon will be killed off/near to extinction/will

giant panda (1) 1 allow any clear indication of the answer

NOT America ignore references to years

allow correct formula eg CO

/CO/SO2/H2O/NO2/NO

2

ignore sulphur oxide/carbon oxide/sulphur trioxide/smoke

if correct name and wrong formula award the mark

if incorrect name and correct formula do not award mark

ignore other characteristics of mammals eg mammals have live young

very dense/jungle difficult to explore

allow 'very rare'/'small numbers'/'an endangered species’ allow ‘nocturnal' allow camouflaged/animals are timid/animals hide

soon disappear

ignore numbers decreasing/population falling

Total 4

31

B622/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

4 a any two from

(better) camouflage (1)

but

(better) camouflage on (dark) trees (2)

not seen by predators (1) fewer eaten (1)

more survive (1)

b

Total 4

500 x 480/60 (1) = 4 000 (1)

2 assume reference to trees are the dark trees unless otherwise

stated

allow they cannot be seen on (polluted) trees/darker just like the trees (2)

allow natural selection has occurred (2) ora for pale moths

2 look for 4 000 as an answer and providing it is a clear answer

ignore working out and award 2 marks allow full marks for correct answer on its own 4 000

32

B622/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

5 a any two from

wood (1)

aluminium (1) lead (1) zinc (1) copper (1)

plastic/named plastic eg polystyrene/poly(chloroethene) (1)

sand/gravel (1)

glass (1)

brick (1) clay (1) breeze block (1)

plaster (1), cement/mortar (1)

fibreglass (1), foam (insulation) (1)

marble (1), slate (1), limestone (1), granite (1) sandstone (1)

b i

alloy (1) 1 allow any correct indication of answer eg alloy ringed

2 allow any other construction material not listed

allow 'metal' or metal (scaffolding) (1) providing marks have not

been awarded for a named metal

ignore iron

allow 'rock'/stone (1) providing marks have not been awarded for a

named rock or stone

allow water

ii

c

Total 5

protection/rust proofing/decoration (1) 1 allow stops steel from corroding/to prolong its life/to make it

contain steel rods

rods/contains metal rods/contain iron

colourful/to make it pretty

1 allow bars/mesh/wire/gauze/beam as alternatives to rod

allow put in a metal stick ignore copper rods NOT contains metal i.e. without reference to a rod

33

B622/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 6 a i

ii b i ii

iii

increases……………..decreases (1) 1 both needed for mark carbon dioxide…………….oxygen (1) 1 both needed for mark nitrogen (1) 1 allow N carbon monoxide/hydrogen/oxygen/nitric oxide (1) 1 allow CO/H

(carbon) monoxide goes down (1) and (carbon) dioxide goes up (1)

c

more surface area/more exposed particles/more area/more surface (1) more collisions (1)

Total 8

7 a

lava (1) 1 allow any correct indication of answer eg lava ringed

/N

2

/NO

2/O2

allow H/O

if more than one answer then all must be correct if correct name and wrong formula award the mark if incorrect name and acceptable formula do not award mark

2 allow carbon monoxide goes from 5.0 to 4.1

allow carbon dioxide goes from 8.0 to 9.6 ignore carbon monoxide goes to 4.1 ignore carbon dioxide goes to 9.6/carbon dioxide is higher than

carbon monoxide

2 ignore more attraction between particles

NOT faster collisions eg more quicker collisions will not score the

more collisions mark

b c

igneous (1) 1 allow any correct indication of answer eg igneous ringed fertile soil/crops grow better/AW (1) 1 answer must address why they still want to live near a volcano

Total 3

and not why they have to live near a volcano allow provided geothermal energy/cheap source of heat/because

scientists may want to study the volcano/want to live in same place as rest of family/housing may be cheap/may want to build a hotel for tourists

ignore because there is no where else to go NOT soil is good unless qualified eg can grow bigger crops

34

B622/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 8 a

b

MgCl

use concentrated acid/more concentrated acid/less

(1) 1 allow hydrogen/magnesium chloride

2/H2

dilute acid (1)

c

particles move faster/particles have more (kinetic) energy (1)

more collisions (per second) (1)

Total 4

allow hydrogen and chloride NOT magnesium chlorine

NOT chloride as only product

1 allow 'add a catalyst'/'stir'/'shake'

allow use non-diluted acid/use higher molar(ity) ignore use stronger acid

ignore use more acid/use more powder

2 allow ora if candidate specifically refers to colder acid

allow more energetic collisions (2) allow more successful collisions (2) allow more particles have enough energy to overcome the

activation energy (1)

ignore acid moving faster NOT faster collisions/not quicker collisions/move around more

35

B622/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

9 a

b

c d

Total 4

10 a

damages living cells/cause cancer/cause a named cancer/radiation

controls cancer/detects cancer/kills cancer cells/cures cancer/kills microbes/tracers/scans/non destructive testing i.e. NDT/smoke detectors/thickness testing (1)

alpha/α (1) 1

paper - YES/tick and aluminium - NO/cross (1)

…coil of wire …. current …magnets………more…. four correct (3) two or three correct (2) one correct (1)

sickness (1)

1 allow kills cells/radiation

mutation/mutation of cells/causes a faulty gene/infertility/hair loss/can kill you

ignore mutates the skin ignore brain damage/skin damage

1 allow food preservation/sterilisation of medical equipment

ignore in power stations/generating electrical energy

1 both needed for 1 mark

3 maximum of three marks

only allow answers from the list

poisoning/burns skin/burns cells/causes

b c Total 5

DC/direct (current) (1) 1 ignore direct electricity AC/alternating (current) (1) 1 ignore alternating electricity/alternative current/alternate current

36

B622/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 11 a

b i

ii

Total 5

high(est) power/more (most) kW/AW (1)

long(est) time/more (most) hours/AW (1)

12 (2)

but

power x time/6 X 2 (1)

cost = 120 (pence)/ ECF from (b)(i) (1) 1 allow £1.20

2 allow 'more current'/more energy (1)

NOT more electricity allow used for longer/takes longer

ignore used more allow higher level answers eg 'most kWh' (2)

2 maximum of two marks

allow full marks for correct answer with or without working

if in doubt with an answer use the one on the answer line

37

B622/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

12 a

b

Total 4

north and south (1) 1 allow N and S

any three from

detected using a compass/detected using a magnet (1)

caused by (molten) iron/nickel (1)

but

caused by iron or nickel moving/caused by currents of (molten) iron or nickel/caused by iron or nickel in the core (2)

but

caused by iron or nickel moving in the core/caused by (molten) iron or nickel currents in the core (3)

idea that there is a 'north and a south pole’/AW (1)

but

north at 'the south pole'/south at 'the north pole' (2)

3

please mark showing ticks and crosses and annotation maximum of three marks can be obtained by answering one bullet

point or two bullet points or all three bullet points

allow one mark for caused by (magnetic) metal in the core/one

mark for caused by (magnetic) metal moving

allow two marks for caused by (magnetic) metal moving in the core

allow use of top and bottom of Earth or Arctic and Antarctic rather

than north pole and south pole

13 a

b

Total 2

getting bigger (1) 1 allow any clear indication of getting bigger gas (cloud)/dust/matter/hydrogen/AW (1) 1 allow nebula/rock grains

ignore rock on its own NOT comets/planets

38

Mark Scheme B622/02

June 2007

Abbreviations, annotations and conventions used in the detailed Mark Scheme.

/ = alternative and acceptable answers for the same marking point

(1) = separates marking points not = answers which are not worthy of credit reject = answers which are not worthy of credit ignore = statements which are irrelevant allow = answers that can be accepted

( ) = words which are not essential to gain credit __ = underlined words must be present in answer to score a mark ecf = error carried forward AW = alternative wording ora = or reverse argument

39

B622/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 1 a

b

c

Total 4

fur/hair (1) 1 allow (external) ears

lives in unexplored area/habitat difficult to access (1)

loss of habitat/loss of food (1) lead to reduction in numbers/extinction (1)

ignore other characteristics of mammals eg mammals have live young

1 allow 'scientists haven't been there'/few people visit there/jungle very

dense/jungle difficult to explore

allow 'very rare'/'small numbers'/'an endangered species allow nocturnal' allow camouflaged/animals are timid/animals hide

2 allow 'disturbance stops breeding'/'loss of nesting sites'

allow absolutes eg ‘no food’ (1) die (1)

loss of nesting site (= loss of habitat)/lost homes (1)

ignore predators (0)

40

B622/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 2 a any two from

(better) camouflage (1)

but

(better) camouflage on (dark) trees (2)

not seen by predators (1) less eaten (1)

more survive (1)

b i

ii any one from

b iii

Total 6

500 x 480/60 (1)AW but = 4000 (2)

sample size may not be large enough (1) flaws in sampling technique eg sampled at different times of day does not take into account movement in/out of ( wood) (1)

predators would see better if on the upper wing/does not spoil camouflage/ predators can’t see them as easily (1)

2 assume reference to trees are the dark trees unless otherwise

stated

allow they cannot be seen on polluted trees/darker just like the trees (2)

allow natural selection has occurred (2) ora for pale moths

2 look for 4 000 as an answer and providing it is a clear answer

ignore working out and award 2 marks allow full marks for correct answer on its own 4 000

1 allow not enough data/evidence AW

allow changes in behaviour patterns (1)

inactivity at certain times of day/type of weather (1)

ignore references to birth & death

1

41

B622/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

3 a

from (increase/more) carbon dioxide (1) global warming/(increased) greenhouse effect/ climate change /melting ice caps/rising sea levels(1)

OR sulphur dioxide (1) oxides of nitrogen (1) acid rain/damages trees/ kills fish/damages buildings (1)

b i

Latin America/Africa/Asia (1) 1 any wrong answer negates mark eg Africa & USA (0)

ii any two from

more cars/vehicles (1) more factories/industry/goods produced/more resources consumed (1) more electricity/energy produced or used (using

fossil fuels)/more fossil fuels (burned) (1)

Total 5

2 must have correct pollutant linked for second mark

allow any reasonable pollution for one mark and its consequence

for second mark eg smoke (1) causes breathing problems

mark example and result together ( can reverse answers)

allow oxides of nitrogen NO

/NO/NO2

x

ozone for results = 0

2 NOT 'more people'

ora eg fewer cars used in Africa NOT merely ‘more affluent'/more developed/more technology

42

B622/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

4 a

b i

ii

Total 5

variation/description of variation/mutation/random fertilisation (1) selection/best adapted survive (1) inheritance of adaptation/gene frequency changes/slow change over generations (1)

net sizes/quotas (1) 1 NOT fishing ban but limit fishing (1)

if not sustained : orca leaves the area (1) tourist industry reduced (1) if sustained orca remain (1) tourist industry unaffected

2 eg wider feet/differences in width (1)

NOT characteristics learnt

more likely to survive (1) wider foot genes passed on (1)

allow fish farming NOT artificial environment

large mesh/reduce quotas (1)

NOT small mesh/increase quotas

assume net size refers to mesh size unless stated otherwise eg use larger net (1) use larger mesh (1) use smaller mesh (0) use smaller net (0)

2 allow example eg hotels lose business

ignore references to human food/fisherman

43

B622/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

5 a

combines hardness of concrete (1) with strength of steel (1)

b

marble is metamorphic rock and limestone is sedimentary rock (1) idea that( particles of) limestone rock are compressed and/or heated together to make marble (1)

Total 4

6 a

nitrogen (1) oxygen any value between 20 and 22 (1)

b

(carbon) monoxide goes down (1) and (carbon) dioxide goes up (1)

c i

carbon monoxide + nitric oxide →carbon dioxide + nitrogen (1)

ii

more surface area/more exposed particles/more area/more surface (1) more collisions (1)

Total 7

2 not merely reinforced concrete is stronger (0) but if implied that

steel makes concrete stronger (1)

allow concrete good under compression AW (1) allow steel good under tension if no other mark reinforced concrete good under

tension/combines best properties of both materials (1)

2 limestone must be named or clearly implied for second marking

point

2 allow N/N

(1) not N

2

or n

3

2 allow carbon monoxide goes from 5.0 to 4.1

allow carbon dioxide goes from 8.0 to 9.6 ignore carbon monoxide goes to 4.1 ignore carbon dioxide goes to 9.6/carbon dioxide is higher than

carbon monoxide

1 allow correct formulae (CO, NO, CO

and N2) or mix of formulae

2

and words

allow correct reactants and products in either order

2 ignore more attraction between particles

NOT faster collisions eg more quicker collisions will not score the more collisions mark

44

B622/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

7 a

b

c

d

Total 5

magma is less dense (than the crust) (1) 1 allow magma lower density not merely magma low density

different type /composition/ viscosity of lava/magma/different pressure/different temperatures (1)

to find out about the structure of the Earth/to predict future eruptions/volcanoes (risks)(1)

idea of convection current of material in the mantle

(1) idea of convection current dragging along the tectonic

plate in the correct direction (1)

1 NOT merely forces

ignore density

1 allow 'to protect lives' (1)

allow evacuation plans (1)

2 all marks an be awarded from a diagram which covers all marking

points to include label of convection current or mantle or plate

plate

mantle

convection current

45

B622/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

8 a

Mg + 2HCl → MgCl

+ H2

2

correct reactants and products (1) correct balancing (1)

b

particles move faster/particles have more (kinetic) energy (1) more collisions (per second) (1)

Total 4

2 allow any correct multiple of this equation

formulae must be correct for balancing mark eg mg(0) H MgCl(0) H(0) MgCl2(0)

= acceptable for arrow NOT and for + ignore state symbol ie (aq)

2 allow ora if candidate specifically refers to colder acid

allow more energetic collisions (2) allow more successful collisions (2) allow more particles have enough energy to overcome the

activation energy (1)

NOT faster collisions/not quicker collisions/move around more

Cl(0)

2

46

B622/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

9 a

b

c i ii any two from

d i

ii

Total 10

…current……magnet………more… all three correct (2) but 1 or 2 correct (1)

(higher voltage) = lower current (1) lower current = less heat loss/reduced temperature (1) but

for the same power voltage increases and current

decreases (2)

cheaper (1) 1 NOT free

available at inconvenient times/inconvenient(1) another meter required/extra wiring/time switches, storage heaters (1) day-time electricity can be more expensive than non

off-peak users/extra standing charge (1)

12 (2)

but

power x time/6 x 2 (1)

cost = 120 (pence)/ ECF from (d)(i) (1) 1 allow £1.20

2 only allow answers from the list

2 ignore references to cost/thinner wires needed (0)

NOT merely recall of P = V x I

2

allow he can only use electrical appliances at night/night time

use only/washing machine noisy at night/risk from unattended appliances = inconvenience

2 maximum of two marks

allow full marks for correct answer with or without working if in doubt with an answer use the one on the answer line

if in doubt with an answer use the one on the answer line

47

B622/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 10 a

b i any two from

ii

Total 4

11 a

b

c

Total 4

paper - YES/tick and aluminium - NO/cross (1)

remains radioactive for a long time (1) terrorist risk (1) easy to remove (1) may get into groundwater /streams/rivers/water supply (1) acceptable radiation level may change in the future (1) harmful to humans/animal /crops /food chain

(1)

encased (1)/buried underground (for a long time) (1)/reprocessed (1)

nearby galaxies move away (1) slower (1) 1 mark (a) and (b) together- award the relative speed mark once

distant galaxies move away (1) quicker (1) 2 mark (a) and (b) together- award the relative speed mark once

all parts of the universe (1) 1 mark answer first- one answer only - look for rings around answer

1 both needed for 1 mark

2

1 NOT recycled

allow terrorist risk/gets into wrong hands NOT nuclear bombs (0) allow dirty bomb (1)

eg presently considered safe levels may in future prove to be

harmful

allow no (completely) safe way found yet

only Universe expanding = move away

NOT galaxies expand allow local galaxies (andromeda) moving closer

only Universe expanding = move away

NOT galaxies expand. allow local galaxies (andromeda) moving closer

Red Shift = moving away

if not on line

48

B622/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

12 any two from

(IR) absorbed ( by wall, floor, furniture, air) (1) (IR) short wavelength entering (1) (IR) longer wavelength emitting (1)

(IR) reflected back in (by glass) (1)

Total 2

2 NOT attracted NOT absorbed by glass NOT light absorbed

allow infrared light absorbed/heat up contents/heats up inside of

conservatory

NOT heats up conservatory allow higher frequency entering (1) allow lower frequency emitting (1)

49

50

Mark Scheme B623/01

June 2007

Abbreviations, annotations and conventions used in the detailed Mark Scheme.

/ = alternative and acceptable answers for the same marking point

(1) = separates marking points not = answers which are not worthy of credit reject = answers which are not worthy of credit ignore = statements which are irrelevant allow = answers that can be accepted

( ) = words which are not essential to gain credit __ = underlined words must be present in answer to score a mark ecf = error carried forward AW = alternative wording ora = or reverse argument

51

B623/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

1 a

1 infancy 2 childhood 3 adolescence 4 maturity infancy just before childhood (1) childhood just before adolescence (1) adolescence just before maturity (1)

2 maximum 2 marks

maximum 1 mark if any answer is in the incorrect position

b i ii

Total 4

2 a i

ii

b

Total 4

5 (years) (1) 1 allow 'between (age) 9 &14'/AW 0 – 1(years) (1) 1 allow ‘first year’

2 (1) 5 4 3

all from same original plant/not from seeds/only one parent (1)

(show) variation/any useful example of variation: eg if one gets disease then not all will/fruit at different times (1)

NOT mass eg 10kg

2 maximum 2 marks

three or four correct (2) one or two correct (1)

1 allow have same DNA/genes

allow clones allow higher level answer cell produced by mitosis

1 allow pollination may depend on presence of different varieties

allow they have different taste/texture/colour/shelf life ignore size/smell

52

B623/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 3 a i

ii iii

b

Total 4

4 a

b

Total 4

DNA (1) 1 more than one answer (0)

nucleus (1) 1 more than one answer (0)

membrane (1) 1 allow cell membrane

diffusion (1) 1 mark answer on line first

bleeds more/faster (from an artery) (1) (because) blood at high(er) pressure (1)

blood clots (1)

because of platelets (1)

2 allow blood pumped/spurts out

2 ignore scab/blood thickens

more than one answer (0)

allow more than one correct answer

more than one answer (0)

2 allow flame over end of tube

NOT O

2

/O2/O/O3

more than one answer (0)

8 a

good conductor of heat (1) high melting point (1)

b

(conduct electricity) with little/no/very small resistance (1)

c any two from

good conductor (of electricity) (1) ductile/can be drawn into wires (1)

flexible (1) so it can bend around corners (1)

Total 5

2 each extra box ticked negates one mark

1

2 allow two properties or one property and a justification

allow low resistance ignore high melting point NOT good heat conductor

55

B623/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

9 a

2 if two lines go to one box score zero for that box

atom

ion

molecule

H2O

Na

He

+

two or three correct (2)

b

2Mg + O

one correct (1)

→ 2MgO

2

correct formulae of reactants and products (1) balancing (1)

Total 4

10 a

b

B (1) 1

A (1) 1

Total 2

2 allow any correct multiple

balancing mark is dependent on getting the reactants and products correct

allow ‘heat’ above arrow

11

apparatus - tape/trundle wheel (1)

measurement - time (1) unit - m/s or m/s-

1

or metres per second (1)

Total 3

3 ignore ‘meter ruler’ but NOT rule/ruler

allow metre wheel/measuring wheel allow mps

56

B623/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

12 a

b

c any two from

d any one from

thinking distance is -the idea of the distance the car moves (1) while the driver reacts/AW (1)

braking distance is the distance the car moves (before stopping) with its brakes on (1)

greater speed AW(1) alcohol/drugs (1) tiredness/illness (1)

distractions/lack of concentration (1)

reduce chance of skidding (1) stop wheels locking (1)

avoid losing control (1)

2 allow how far (1) NOT 'how long' NOT the 'time'

eg time it takes you to know you have to brake and putting your foot on the brake = 1 eg distance taken for the driver to think = 1 eg distance taken for the driver to think before taking action/braking = 2 eg distance car moves while the driver reacts = 2

eg allow time to react/idea of reaction time = 1

1 allow how far

eg distance in which car was breaking = 1

NOT distance car goes before stopping

2 NOT merely speed (0)

allow older ignore weather conditions

1

Total 6

13 a

b Total 2

van (1) 1 mark answer on line first

450 or 30 x 15 scores (1) 1 ignore units

more than one answer scores zero

2 allow any correct multiple

balancing mark is dependent on getting the reactants and products

correct

2 allow two properties or one property and a justification

allow low resistance ignore high melting point NOT good heat conductor

c

(conduct electricity) with little/no/very small resistance (1)

Total 4

1

62

B623/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

9 a

2Mg + O

→ 2MgO (2)

2

correct formulae of reactants and products (1) balancing (1)

b

drawing of oxide ion 2,8 and of magnesium ion 2,8 (1) correct charges O

2-

and Mg2+ (1)

Total 4

10 a any two from

floats on water/moves on water (1) fizzes/bubbles/spits/pops/violent (reaction)/AW (1) lilac flame/pink flame (1) melts/turns into a molten ball/AW (1) colourless solution produced (1)

colourless gas/hydrogen gas produced (1)

b

potassium loses electrons more easily than sodium/potassium needs less energy to lose an electron/ora/AW (1)

c

hydrogen (1) rubidium hydroxide (1)

2 allow any correct multiple

balancing mark is dependent on getting the reactants and products correct

allow ‘heat’ above arrow

2 charges independent of dot and cross diagrams

allow a full written explanation for both marks NOT donated electrons appearing in both

2 allow white smoke

NOT just ‘reaction’ must be ‘violent‘ (1) allow coloured flame

1 NOT potassium loses electrons faster/potassium loses more

electrons

2 allow H /H

allow RbOH

2

Total 5

63

B623/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

11 a any two from

greater speed/AW (1) alcohol/drugs (1) tiredness/illness (1)

distractions/lack of concentration (1)

b any one from

reduce chance of skidding (1) stop wheels locking (1)

avoid losing control (1)

c i ii

13 (m) (1) 1

0.75 (s) (2) but 6/8 or 12/16 or 24/32 (1)

iii

thinking distance needed is greater than 15m/AW (1) driving within thinking distance/AW (1) too close (to car in front) (1) collision risk (1)

iv

KE is absorbed when braking /AW(1) when speed doubles braking distance quadruples/more than doubles (1) when speed doubles KE quadruples/KE α v

2

(1)

2 NOT merely speed (0)

allow older ignore weather conditions eg foggy (0)

1

2

2 NOT just KE formula

Total 10

64

B623/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

12 a

b

Total 2

13 a

b any two from

Total 3

14

Total 2

increases/AW (1) 1

absorb energy (1) 1 allow change shape (1) higher level answers in terms of

450 or 30 x 15 scores (1) 1 ignore units

different: driving styles /AW (1) journey lengths/AW(1) speeds (1) loads (1)

road conditions AW (1)

W = 1 000 (2) but W = 500 x 2 scores (1)

acceleration (1) less acceleration/force (1)/greater ‘stopping’ distance/time (1) change to heat (1)/

NOT change to elastic energy (0)

2 allow ‘wind’ if qualified eg driving into the wind (1)

allow ideas of a cold engine (1) ignore size/type of van

2

15 a any three from

roof box creates more drag/AW (1) (car has )lower (terminal) speed (1) force balance at terminal speed /AW (1)

Total 3

3

65

66

Mark Scheme B631/01

June 2007

Abbreviations, annotations and conventions used in the detailed Mark Scheme.

/ = alternative and acceptable answers for the same marking point

(1) = separates marking points not = answers which are not worthy of credit reject = answers which are not worthy of credit ignore = statements which are irrelevant allow = answers that can be accepted

( ) = words which are not essential to gain credit __ = underlined words must be present in answer to score a mark ecf = error carried forward AW = alternative wording ora = or reverse argument

67

B631/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

1 a

b

c

Total 6

37°C (1) 1 if no ring drawn accept other indication eg underline or tick

every incorrect answer negates a correct answer

1. his respiration becomes faster (1)

3. he shivers more (1)

oxygen (1) glucose (1) heart (1)

2 if no ticks shown accept other indication eg underline or ring

if more than 2 ticks then deduct one mark for each incorrect tick

3 or vice versa

2 a

b

Total 5

genes (1) nucleus (1) asexual (1) clones (1)

mutation (1) 1 if no ring drawn accept other indication eg underline or tick

4

if part (i) is wrong allow genes instead of nucleus

every incorrect answer negates a correct answer

68

B631/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 3 a

b i ii

iii any two from

iv

Total 6

D (1) 1 allow lettuce/vitamin C

3 (1) 1 mark answer line first - if blank look for answer in working

growth/repair/make new cells (1) 1 allow higher level answers eg (to make)

come from an animal (1)

contain essential amino acids (1)

contain amino acids that cannot be made by the body

(1)

liver/brain (1) 1 every incorrect answer negates a correct answer

2

NOT C alone

every incorrect answer negates a correct answer

enzymes/hormones/membrane

allow make muscles stronger ignore make you stronger

ignore meat allow contains amino acids that are necessary in the diet

69

B631/01 Final Mark Scheme June 2007

p

y p

Question Expected Answers Marks Rationale

4 a

b

fungi/virus/protozoa (1) 1 allow any correct named examples

2 all three correct (2)

antibody

antigen

toxin

a chemical on the surface on

athogens

a chemical released by white blood cells

a chemical that is produced and released b

athogens

Total 3

NOT named example of bacteria eg MRSA

every incorrect answer negates a correct answer

NOT microbe/germ

1 or 2 correct (1)

if more than one line from a box on the left then no mark for that box

ignore any incorrect lines from right hand boxes

70

B631/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

5 a i

ii any two from

b

Total 4

6 a

b i

ii c any two from

Total 5

photosynthesis (1) 1 if no ring drawn accept other indication eg underline or tick

stored (1) turned into starch (1) energy/respiration (1)

growth/(to make) named part of a plant eg leaves(1)

fish (1) 1 if no tick shown accept other indication eg underline or ring

mammals (1) 1 if no answer written on answer line look for indication in list

predator (1) 1 allow carnivore

prey (1) 1 ignore consumer

claws (1) sharp teeth (1) camouflage (1) built for speed (1) strong/large size (1)

good sense of smell (1)

every incorrect answer negates a correct answer

2 allow higher answers turned into protein/fat/oil/cellulose/sucrose (1

mark each)

ignore food

ignore sap

every incorrect answer negates a correct answer

an incorrect answer negates a correct answer

allow secondary/tertiary/quaternary consumer NOT hunter

2 ignore adaptations for cold/references to eyesight/swimming ability

ignore teeth allow white ignore just ‘can run’

71

B631/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

7 a

b any one from

c

d i

green head (1) grey body (1)

food (1) mate (1) water (1)

nesting material/nesting sites/nests (1) feathers/beak (1) 1 reject wings unless qualified with feathers

goes down then up (1)

quantify description at start, lowest point or end (1)

2 if give more than 2 answers, every incorrect answer negates a

correct answer

1

reject fly

an incorrect answer negates a correct answer

2 eg lowest in 1977/after ten or/eleven years

or increases from 1978 or lowest number between 10 and 30 or starts from 520 – 580 or maximum or ends at 1100 – 1150 or doubles between start and end

ignore comments about rate of change ignore incorrect references to figures

72

B631/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

7 d ii any one from

protect habitat/AW(1)

legal protection/AW (1)

captive breeding/AW(1)

education of people/AW (1)

qualified idea of reducing competition with ruddy ducks/AW (1)

reproductive technologies/AW (1)

Total 7

1 eg set up reserves allow put in artificial ecosystem

allow stop hunting/poaching

eg make laws against killing or taking eggs

eg breed them in zoos ignore put in zoos allow breed them ignore selective breeding

eg increase public awareness of the problem

eg feed them

eg freezing sperm/eggs/embryos/cloning

73

B631/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

8 a

b

c any two from

Total 4

9 a i

ii

b

extinct (1) 1 NOT endangered/dead

dodo (1) 1 if no ring drawn accept other indication eg underline, tick

covered by sediment (1)

soft parts decay (1)

(hard) parts replaced by mineral/mineralisation (1)

tail (1) to swim/move (to egg) (1) OR small size (1) more can be produced/to enter egg (1) OR acrosome (1) to digest egg membrane (1) OR mitochondria (1) (for) energy to swim (1)

more chance of reaching/fertilising egg (1) 1 allow idea that many will not reach the egg

6 (1) 1 every incorrect answer negates a correct answer

every incorrect answer negates a correct answer

2 allow covered by mud/tar/amber/ice ignore rock/earth/soil

allow hard parts/bones do not decay

2 must have correct linkage to get 2 marks

NOT just 'shape' or 'size' i.e. needs qualification allow lack of cytoplasm (1) no need for (large) food store (1)

allow so that at least one reaches/fertilises egg

Total 4

74

B631/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

10 a

b Total 4

idea that have light from one side only (1)

idea of observations (of orientation) before and after (1)

a valid specific eg of fair testing (1)

positive phototropism (1) 1 if no answer on the line accept indication on the list

3 allow put on window sill/by window/in box with hole

allow see which way they grow/if they grow towards

hole/window

ignore see if they grow towards light (in question) allow see if bend towards light

ignore keep things the same allow idea of comparison with control (1)

75

B631/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 11 a

lungs/alveoli (1) carbon dioxide/CO

(1)

2

(small) intestine (1)

b

B (1) 1 every incorrect answer negates a correct answer

Total 4

12 a

b i

2

all points correctly plotted to within +/- 0.5 square (1)

smooth line of best fit (1)

ii

8 (1) 1 allow answer in range 7 – 9

Total 5

3

allow water allow higher level answers: duodenum/ileum/villi

if no answer on the line accept indication on the list

all three correct (2) 1 or 2 correct (1)

if more than one line from a box on the left then no mark for that box

ignore any incorrect lines from right hand boxes

2

reject double/feathery lines/lines more than ½ sq thick

lose smooth line mark if extend line towards origin

if graph is incorrect allow ECF

76

B631/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

13 a

b

Total 3

C/high milk production (1) E/resistance to disease (1)

(no/maybe - no mark) may get small number/small/sour apples (1)

2 in either order

if give more than 2 answers every incorrect answer negates a correct answer

1 allow higher level answer: get variation

allow you may get a mixture of different types eg large &

small/medium

allow still have genes for small/sour

77

78

Mark Scheme B631/02

June 2007

Abbreviations, annotations and conventions used in the detailed Mark Scheme.

/ = alternative and acceptable answers for the same marking point

(1) = separates marking points not = answers which are not worthy of credit reject = answers which are not worthy of credit ignore = statements which are irrelevant allow = answers that can be accepted

( ) = words which are not essential to gain credit __ = underlined words must be present in answer to score a mark ecf = error carried forward AW = alternative wording ora = or reverse argument

79

B631/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

1 a

b

2 all three correct (2)

antibody

antigen

toxin

a chemical on the surface on pathogens

a chemical released by white blood cells

a chemical that is produced and released by pathogens

may not be bacteria or fungus / may be a virus/protozoa / may be resistant (1)

c

resistant bacteria may survive (1)

resistant bacteria reproduce (1)

resistant bacteria may produce a resistant strain (1)

Total 5

1 or 2 correct (1)

if more than one line from a box on the left then no mark for that box

ignore any incorrect lines from right hand boxes

1 allow not completing course (1)

allow if dose is insufficient/drug not strong enough (1) allow may stop pathogen reproducing (1)

2 reject the antibiotic makes the bacteria resistant/makes a resistant

strain

allow some people may not develop a natural immunity (1) allow side effects/allergies (1)

80

B631/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 2 a

b i ii any two from

iii

c

Total 6

D (1) 1 allow lettuce/vitamin C

3 (1) 1 mark answer line first - if blank look for answer in working

come from an animal (1)

contain essential amino acids (1)

contain amino acids that cannot be made by the

body (1)

religious/cultural reasons /

ethical reasons/

food allergies/health reason qualified (1)

it breaks down/removes/ filters alcohol/toxins/substances (from the blood)/

idea that blood passes through the liver before it reaches other organs (1)

NOT C alone

every incorrect answer negates a correct answer

2 ignore meat

allow contains amino acids that are necessary in the diet

1 eg in hot countries heat is more likely to cause food poisoning

eg it is cruel

eg contains a lower saturated fat content

ignore don’t like the taste

1 reject stores alcohol

81

B631/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

3 a

b any three from

Total 4

4 a

b

c any three from

Total 5

hypothermia

body/core temperature is rising/high (1)

increase detected by the brain (1)

vasodilation/blood vessels in the skin widen (1)

more blood flowing close to the skin (1)

to lose more heat/more radiation (1)

fertilisation (1) 1 ignore fusion

protein/(poly)peptide/mRNA/RNA/(1) 1 ignore amino acids/named proteins/enzymes

mutation is a change in a gene/DNA/genetic material (1)

(may) change base sequence/amino acid sequence(1)

protein is altered or not made (1)

if an enzyme the reaction does not occur/occurs at

different rate(1)

(1) 1 spelling must be clearly different to hyperthermia

3

ignore he is getting hotter/warmer accept hypothalamus reject incorrect brain regions reject move closer to the skin/veins accept bigger

must be an increase

3 change in DNA base sequence = 2

accept different protein is made

82

B631/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

5 a

b i

ii any one from

Total 4

feathers/beak (1) 1 reject wings unless qualified with feathers

goes down then up (1)

quantify description at start lowest point or end (1)

protect habitat/AW(1)

legal protection/AW (1)

captive breeding/AW(1)

education of people/AW (1)

idea of reducing competition with ruddy ducks/AW (1)

reproductive technologies/AW (1)

an incorrect answer negates a correct answer

2 eg lowest in 1977/after ten or/eleven years /increase starts in

1978 or lowest number between 10 and 30 or starts from 520 – 580 or maximum or ends at 1100 – 1150

ignore comments about rate of change ignore incorrect references to figures

1 eg set up reserves

allow stop hunting/poaching accept artificial ecosystem

eg make laws against killing or taking eggs

eg breed them (in zoos) ignore put in zoos

eg increase public awareness of the problem

eg feed them

eg freezing sperm/eggs/embryos/cloning

83

B631/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

6 a any two from

covered by sediment (1)

soft parts decay (1)

(hard) parts replaced by minerals /mineralisation (1)

b any two from

all parts may decay (1)

fossilisation is rare (1)

many fossils not yet discovered (1)

c i

ii

Total 6

Lamarck - characteristics gained during lifetime/organisms become adapted during their life /

Darwin - born with characteristic/best suited survive (1)

both involved variation/adaptation/change

2

allow covered by tar/amber/ice/mud ignore rock/earth/soil allow hard parts/bones do not decay

2

allow some organisms have not fossilised/most organisms do not fossilise ignore the type of organism

1 answers only need to give views of one of the scientists

allow suitable examples

1

84

B631/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

7 a any two from

colourful/petals are large (1) nectar (1) sticky pollen (1) enclosed anthers/stigma (1)

scented (1)

b i

ii any two from

c

Total 7

carbon dioxide on LHS, oxygen on RHS (1)

more (sun)light (1)

higher/increasing temperature/more heat(1)

more carbon dioxide (1)

bacteria - gain sugars/glucose (1)

pea - gain nitrates/nitrogen compounds (1)

2

reject just bright/plant is colourful

reject

anthers are not feathery

1 both needed for mark

accept symbols if correct

2 must qualify answer

ignore sun

allow more chlorophyll (1) ignore water/minerals

2 ignore food

accept amino acids reject nitrogen

85

B631/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

8

any three from

hare numbers increasing/high because less lynx to eat them (1)

lynx numbers increasing/high as there are more hares to eat (1)

hare numbers low/decrease as more lynx to eat them (1)

lynx numbers decrease/low as less hares to eat (1)

Total 3

9 a i

ii

b i

ii

Total 4

6 (1) 1 every incorrect answer negates a correct answer

12 (1) 1 every incorrect answer negates a correct answer

D (1) 1 every incorrect answer negates a correct answer

A (1) 1 every incorrect answer negates a correct answer

3

reject die out or become extinct (once only) ignore descriptions must be an explanation

if no answer on the line accept indication on the list

86

B631/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 10 a

b

Total 4

11 a

b i ii any two from

Total 4

positive phototropism (1) 1 if no answer on the line accept indication on the list

auxin (1)

collects on/sent to/passes to shady side/higher concentration on shady side (1)

causes cell elongation (1)

B (1) 1 every incorrect answer negates a correct answer

alveoli (1) 1 allow alveolus

greater surface area (1)

better blood supply/more vessels (1)

greater concentration difference (1)

3 accept IAA

not causes growth not causes cell division

if no answer on the line accept indication on the list

2

answers must be comparative

87

B631/02 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale 12 a i

ii

b

Total 4

13 a any two from

b any two from

Total 4

all points correctly plotted to within +/- 0.5 square (1)

smooth line of best fit (1)

8 (1) 1 allow answer in range 7 – 9

amylase denatured/ active site changed/ starch/substrate does not fit into active site(1)

chooses fastest dogs from offspring (1) breed them (1) repeat (1)

if different parents then less accumulation of harmful (recessive) characteristics/inbreeding depression (1)

if different parents then more variation (1)

if different parents then increases the gene pool (1)

2 reject double/feathery lines/lines more than ½ sq thick

lose smooth line mark if extend line towards origin

if graph is incorrect allow ECF

1 not 'killed'

2 must be clear that the fastest dogs are being bred

cannot score without either of the first two marking points

2 accept converse for each point if clear which is being referred to

ignore inbreeding unless qualified eg runts accept less genetic disorders

reject no variation

88

Mark Scheme B641/01

June 2007

Abbreviations, annotations and conventions used in the detailed Mark Scheme.

/ = alternative and acceptable answers for the same marking point

(1) = separates marking points not = answers which are not worthy of credit reject = answers which are not worthy of credit ignore = statements which are irrelevant allow = answers that can be accepted

( ) = words which are not essential to gain credit __ = underlined words must be present in answer to score a mark ecf = error carried forward AW = alternative wording ora = or reverse argument

89

B641/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

1 a i

ii

b

c any two from

Total 5

fractional distillation (1) 1 allow 'distillation'/‘fractionation’

boiling points (1) 1 NOT 'melting point'

oil spill/damage to wildlife/kills fish/kills sealife/kills marine animals/damages beaches/aw/other specified pollution (1)

converts large molecules to small/breaks (large molecules) to small(er) molecules (1)

small molecules are more useful/makes petrol (1)

makes alkenes (for polymers)/makes ethene/named alkenes/make small alkanes or named alkanes (1)

ideas about oil refinery matching supply to demand/AW(1) and example (1)

allow indication of the correct answer from the list by √, __ or

circling- note that the answer on the line takes precedence

allow indication of the correct answer from the list by √, __ or circling- note that the answer on the line takes precedence

1 allow harms wildlife/animals

allow specific effect on wildlife, eg oil/tar on bird’s feathers ignore catching fire/producing black clouds NOT 'causes pollution' unless qualified

2 allow hydrocarbon as molecule

ignore particles or substances do not credit fractional distillation/mixing other fractions with

petrol/using other fractions instead of petrol

allow monomer as small molecule ignore hydrogen produced

large alkanes to small alkanes scores (2) allow equations either word or symbol

eg decane → octane + ethene scores (2) decane → octane + ethane scores (1) if symbols given, equations need not balance and ignore incorrect subscripts/ superscripts

possible example is lubricating oil/ fuel oil changed into petrol scores (2)

90

B641/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

2 a i

ii

b c

d any two from

Total 7

monomers (1) 1 allow any suitable indication of the correct answer from the list. Note

polymers (1) 1 allow any suitable indication of the correct answer from the list. Note

poly(ethene) (1) 1 allow 'polyethene'/'polythene'

carbon (1) hydrogen (1)

do not rot/do not decompose/not chemically broken down/not biologically broken down (1)

use up (valuable) space (1)

idea of a (valuable) resource being used up (1)

animals choke (1)

that the answer on the line takes precedence.

2 allow any order

not atomic symbols

2 allow decomposes or rots over a long period of time

ignore disintegrates/deteriorates/degrades/unqualified references to

broken down

allow landfill sites get filled up (more quickly)/need more and more

landfill sites/ difficult to get a licence for landfill site/not many landfill sites left

ignore smells allow throwing away plastics which can be reused or recycled ignore poisons/harms/damage animals

ignore damage wildlife

91

B641/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

3 a

b

oxygen (1) 1 allow O

water/hydrogen oxide (1) carbon dioxide (1)

c

carbon monoxide (1) 1 allow CO

Total 4

2

2 allow steam/water vapour/H

allow CO

2

ignore wrong formula if name correct allow any order

2

O

92

B641/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

4 a

b c

d

6 (1) 1 allow 6 next to the words ‘finish the table’ or next to the table if

B (1) 1 if answer to part a is greater than 9 then correct response is A Exothermic (1) 1 allow indication of the correct answer from the list by √, __ or

C

O (1) 1 allow C

2H6

Total 4

5 a any two from

sand (1) water (1)

stones/AW (1)

b i

ii

CaCO

thermal decomposition (1) 1 allow 'decomposition'

→ CaO + CO2 (1) 1 allow any correct multiple

3

Total 4

clearly unambiguous

ignore 22-16

circling- note that the answer on the line takes precedence

OH

2H5

allow any order of symbol reject superscripts or incorrect subscripts

2 allow hydrogen oxide/H

allow 'gravel' for stones/‘aggregate’ ignore rock/mud/calcium oxide/lime/clay

allow = /

⇋

NOT and / + heat ignore state symbols

allow indication of the correct answer from the list by √, __ or

circling- note that the answer on the line takes precedence

2

O

93

B641/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

6 a

nitrogen (1) oxygen (1)

b i

ii

c

photosynthesis (1) 1 allow any suitable indication of the correct answer from the list-note

respiration (1) 1 allow any suitable indication of the correct answer from the list- note

burning fossil fuels/burning sulfur / volcanoes/hot springs/geysers/ sulfur reacting with oxygen/ striking matches (1)

Total 5

7 a

60 (1) 1 allow correct numerical answers written on graph

b

graph rises more steeply from origin (1) levels off at same volume (1)

c any two from

increase concentration (of acid)/use concentrated acid (1) increase surface area/reduce particle size/make into a powder/crushing tablets/AW (1) add a catalyst (1)

shake/stir (1)

Total 5

2 allow any order

allow N

, O2, N and O

2

that the answer on the line takes precedence

1 allow burning coal/burning oil/burning gas/petrol/diesel

ignore burning methane/octane etc/burning in cars/power stations

unit not needed

2 graph must have same general shape as original

if goes more than one ‘square’ above highest in original penalise levels off at same volume mark line must end up at same volume as original (need not join original line)

ignore quality of line

mark two points independently.

2 allow use undiluted acid/use stronger acid/decrease pH/more acidic

ignore use a stronger tablet/use more tablets/increase/change the temperature

94

B641/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

8 a

b

plastic/glass/leather/rubber (1) 1 allow named plastic/polymer eg polyester, polyurethane

allow any order

water (1) air/oxygen (1)

c

idea of a mixture of at least two elements one of which is a metal (1)

d

any two from

oxide layer/layer of aluminium oxide(1) coherent/does not flake away/AW (1) layer is impermeable to water/impervious layer/ protective layer (1)

Total 6

ignore named elements eg carbon/metals if more than one

response is given

2 allow rain/H

allow O

O (formula must be correct)

2

(formula must be correct)

2

allow 'moist air' (2) allow 'damp air' (2)

ignore steam

1 ignore named alloys

reject metal and non-metal/2 metals together/combination of metals

2 ignore aluminium less reactive

allow prevent reaction with air/ oxygen

95

B641/01 Final Mark Scheme June 2007

Question Expected Answers Marks Rationale

9 a

b

c d

atom Na ion K molecule O

+

(2)

2

gains electrons (1) 1 allow adds electrons/gets an extra electron/gains one

elements (1) 1 allow 'atoms' covalent (bonding) (1) 1 allow convalent

Total 5

2 all three correct (2)

one or two correct (1)

allow any suitable indication of pairing reject for each box if multiple lines from that box

electron/reduction

ignore number of electrons reject chloride ions gain electrons

96

OCR J640, J645 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual