Version : 1.0 0209

abcGeneral Certificate of Education Chemistry 1421 CHEM1 Foundation Chemistry

Mark Scheme 2009 examination - January series

Mark schemes are prepared by the Principal Examiner and considered, together with the relevant questions, by a panel of subject teachers. This mark scheme includes any amendments made at the standardisation meeting attended by all examiners and is the scheme which was used by them in this examination. The standardisation meeting ensures that the mark scheme covers the candidates’ responses to questions and that every examiner understands and applies it in the same correct way. As preparation for the standardisation meeting each examiner analyses a number of candidates’ scripts: alternative answers not already covered by the mark scheme are discussed at the meeting and legislated for. If, after this meeting, examiners encounter unusual answers which have not been discussed at the meeting they are required to refer these to the Principal Examiner. It must be stressed that a mark scheme is a working document, in many cases further developed and expanded on the basis of candidates’ reactions to a particular paper. Assumptions about future mark schemes on the basis of one year’s document should be avoided; whilst the guiding principles of assessment remain constant, details will change, depending on the content of a particular examination paper.

Further copies of this Mark Scheme are available to download from the AQA Website: www.aqa.org.uk Copyright © 2009 AQA and its licensors. All rights reserved. COPYRIGHT AQA retains the copyright on all its publications. However, registered centres for AQA are permitted to copy material from this booklet for their own internal use, with the following important exception: AQA cannot give permission to centres to photocopy any material that is acknowledged to a third party even for internal use within the centre. Set and published by the Assessment and Qualifications Alliance. The Assessment and Qualifications Alliance (AQA) is a company limited by guarantee registered in England and Wales (company number 3644723) and a registered charity (registered charity number 1073334). Registered address: AQA, Devas Street, Manchester M15 6EX Dr Michael Cresswell Director General

Che

mis

try -

AQ

A G

CE

Mar

k S

chem

e 20

09 J

anua

ry s

erie

s

3

Que

stio

n P

art

Sub

Par

t M

arki

ng G

uida

nce

Mar

k C

omm

ents

1 (a

)

Par

ticle

R

elat

ive

Cha

rge

Rel

ativ

e m

ass

Pro

ton

+1

1

Neu

tron

0 1

1 1

Nee

d +1

for p

roto

n

1 (b

)

d bl

ock/

D b

lock

; 1

Or D

or d

1 (c

) (i)

74

; 1

Not

74.

0

1 (c

) (ii

) 11

2;

1 N

ot 1

12.0

1 (d

) (i)

To

acc

eler

ate/

mak

e go

fast

er;

To d

efle

ct/ t

o be

nd th

e be

am;

1 1

Any

ord

er

Not

just

attr

act t

o ne

gativ

e pl

ate

1 (d

) (ii

) E

lect

rom

agne

t / m

agne

t / e

lect

ric fi

eld

/acc

eler

atin

g po

tent

ial o

r vol

tage

; 1

Not

ele

ctric

cur

rent

N

ot e

lect

roni

c fie

ld

1 (e

)

Non

e/ n

othi

ng;

Sam

e nu

mbe

r of e

lect

rons

(in

oute

r orb

ital/s

hell)

/ bot

h ha

ve 7

4 el

ectro

ns/

sam

e el

ectro

n co

nfig

urat

ion;

1 1

If bl

ank

mar

k on

. If

inco

rrec

t CE

= 0

N

ot ju

st e

lect

rons

de

term

ine

chem

ical

pr

oper

ties

Igno

re p

roto

ns a

nd

neut

rons

unl

ess

wro

ng

stat

emen

t.

1 (f)

(182

2

6.4)

+ (1

83

14.

3) +

(184

3

0.7)

+ (1

86

28.

6) ;

100

=

183.

90;

allo

w ra

nge

from

183

.90

– 18

4.00

;

1 1

If tra

nscr

iptio

n er

ror t

hen

M1

= A

E =

-1 a

nd m

ark

M2

cons

eque

ntia

lly

Che

mis

try -

AQ

A G

CE

Mar

k S

chem

e 20

09 J

anua

ry s

erie

s

4

Que

stio

n P

art

Sub

Par

t M

arki

ng G

uida

nce

Mar

k C

omm

ents

2 (a

)

Abi

lity/

pow

er o

f an

atom

/ele

men

t/nuc

leus

to w

ithdr

aw e

lect

ron

dens

ity o

r ele

ctro

n cl

oud

or a

pai

r of e

lect

rons

(tow

ards

itse

lf);

From

a c

oval

ent b

ond

or fr

om a

sha

red

pair

of e

lect

rons

;

1 1

Not

with

draw

an

elec

tron

If re

f to

ioni

c, m

etal

lic ,

imf e

tc th

en

CE

= 0

N

ot d

isto

rt N

ot re

mov

e el

ectro

ns

2 (b

)

Van

der

Waa

ls/ v

dw/L

ondo

n/ te

mpo

rary

(ind

uced

) dip

ole/

di

sper

sion

forc

es;

Hyd

roge

n bo

nds/

H b

onds

;

1 1

Not

just

hyd

roge

n

2 (c

)

(Lar

ge) e

lect

rone

gativ

ity d

iffer

ence

bet

wee

n N

+ H

/ diff

eren

ce

of 0

.9/ N

ver

y el

ectro

nega

tive;

Fo

rms

N δ

- / H

δ+

or d

ipol

e ex

plai

ned

in w

ords

; Lo

ne p

air o

n N

attr

acts

/form

s w

eak

bond

s w

ith H

(δ+)

;

1 1 1

Insu

ffici

ent t

o sa

y N

= 3.

1 an

d H

=

2.1

Not

N b

ecom

es (f

ully

) neg

ativ

e or

vi

ce v

ersa

Q

WC

C

an s

core

M2

and

3 fro

m a

dia

gram

2 (d

)

Co-

ordi

nate

/dat

ive;

B

oth

elec

trons

/ lon

e pa

ir (o

n P

/PH

3)

Sha

res/

dona

ted

from

P(H

3)/ t

o H

(δ+)

;

1 1 1

If no

t cor

rect

then

CE

= 0

. If

cova

lent

/bla

nk m

ark

on.

Not

lone

pai

r on

hydr

ogen

2 (e

)

3 bo

nds

and

1 lp

atta

ched

to A

s;

Pyr

amid

al/te

trahe

dral

/ trig

onal

pyr

amid

al;

1 1

Mus

t lab

el H

and

As

atom

s A

ccep

t dis

torte

d te

trahe

dral

not

ben

t te

trahe

dral

N

ot b

ipyr

amid

al/tr

iang

ular

2 (f)

(Onl

y) w

eak

Van

der

Waa

ls fo

rces

bet

wee

n m

olec

ules

/AsH

3 ha

s w

eake

r IM

F /a

mm

onia

has

hyd

roge

n bo

ndin

g/ m

ore

ener

gy n

eede

d to

bre

ak IM

F’s

in a

mm

onia

/ Van

der

Waa

ls

wea

ker t

han

H b

onds

;

1 A

ccep

t has

no

H b

onds

. Ig

nore

dp-

dp in

AsH

3 p

rovi

ded

amm

onia

has

stro

nger

IMF.

If

betw

een

atom

s m

entio

ned

CE

=0

Bre

ak b

onds

CE

= 0

Che

mis

try -

AQ

A G

CE

Mar

k S

chem

e 20

09 J

anua

ry s

erie

s

5

2 (g

)

4AsC

l 3 +

3 N

aBH

4 4

AsH

3 + 3

NaC

l + 3

BC

l 3 ;

1 A

ccep

t mul

tiple

s Q

uest

ion

Par

t S

ub P

art

Mar

king

Gui

danc

e M

ark

Com

men

ts

3 (a

) (i)

7

9.9

100

; 22

5.9

=

35.3

7(%

) a

llow

35.

0 –

35.4

%;

1 1

Who

le e

xpre

ssio

n Ig

nore

>3

sig

figs

Allo

w 3

5%

Allo

w 2

mar

ks if

cor

rect

%

3 (a

) (ii

) S

ell t

he H

Cl

or s

ell t

he o

ther

pro

duct

or s

ell t

he a

cid

(form

ed

in th

e re

actio

n);

1 N

eed

a fin

anci

al g

ain

3 (b

) (i)

1

65

= 0

.869

; 18

9.9

al

low

0.8

6 –

0.87

;;

2 O

ne m

ark

for M

r = 1

89.9

Ig

nore

uni

ts

3 (b

) (ii

) 0.

869

1 A

ccep

t sam

e va

lue

as in

(i)

3 (b

) (ii

i) 0.

869

79.

9 =

69.4

; A

llow

68.

7 –

70;

1 A

ccep

t ans

wer

to (i

i) 7

9.9

3 (b

) (iv

) 6

3

100

; 69

.4

= 90

.75%

; A

ccep

t 90.

6 to

92%

;

1

Acc

ept 6

3 x

100

/ans

wer

to (i

ii)

If >1

00%

lose

this

mar

k

Che

mis

try -

AQ

A G

CE

Mar

k S

chem

e 20

09 J

anua

ry s

erie

s

6

Que

stio

n P

art

Sub

Par

t M

arki

ng G

uida

nce

Mar

k C

omm

ents

4 (a

) (i)

E

nerg

y/en

thal

py (c

hang

e)/∆

H/ n

eede

d to

rem

ove

1 m

ole

of

elec

trons

; Fr

om 1

mol

of g

aseo

us a

tom

s;

1 1

Allo

w 1

ele

ctro

n N

ot h

eat a

lone

Fr

om 1

gas

eous

ato

m

Not

mix

and

mat

ch m

oles

and

on

e el

ectro

n.

Allo

w 1

for b

alan

ced

eq w

ith s

s

4 (a

) (ii

) In

crea

se;

Incr

easi

ng n

ucle

ar c

harg

e/ in

crea

sing

num

ber o

f pro

tons

; S

ame

or s

imila

r shi

eldi

ng /s

ame

num

ber o

f she

lls o

r ene

rgy

leve

ls/ (

atom

ic) r

adiu

s de

crea

ses/

elec

tron

clos

er to

nuc

leus

;

1 1 1

If bl

ank

mar

k on

If

inco

rrec

t CE

= 0

N

ot in

crea

sing

ato

mic

num

ber

Not

sam

e di

stan

ce fr

om

nucl

eus.

4 (a

) (ii

i) A

lum

iniu

m/A

l; E

lect

ron

in h

ighe

r ene

rgy

/p o

r 3p

orbi

tal;

Less

ene

rgy

need

ed to

lose

ele

ctro

n/ e

lect

ron

mor

e ea

sily

lo

st/ i

onis

atio

n en

ergy

less

;

1 1 1

If in

corr

ect C

E =

0

Not

2p

Igno

re s

hiel

ding

4 (b

)

Sili

con/

Si;

Mac

rom

olec

ular

/ Gia

nt m

olec

ular

or a

tom

ic o

r cov

alen

t; M

any

or s

trong

cov

alen

t bon

ds n

eed

to b

e br

oken

/ lo

ts o

f ene

rgy

need

ed to

bre

ak th

e co

vale

nt b

onds

;

1 1 1

If in

corr

ect C

E =

0

If si

licon

e, s

ilica

Si 8,

Si 4

mar

k on

. If

IMFo

r ion

ic o

r met

allic

in

Sili

con

then

CE

= 0

for

expl

anat

ion

Not

loos

ened

bon

ds

Che

mis

try -

AQ

A G

CE

Mar

k S

chem

e 20

09 J

anua

ry s

erie

s

7

Que

stio

n P

art

Sub

Par

t M

arki

ng G

uida

nce

Mar

k C

omm

ents

5 (a

) (i)

0.

013;

1

5 (a

) (ii

) 0.

0065

; 1

Ans

wer

to (i

) ÷ 2

5 (a

) (ii

i) 0

.548

= 8

4.3;

0.

0065

1

Allo

w 0

.548

÷ a

nsw

er to

(ii)

Allo

w 8

4.1

– 84

.4

5 (b

)

84.3

– 6

0 =

24.3

; M

g;

If 14

7.6

used

the

answ

er is

87.

6 (1

) A

nd th

is is

Sr (

1)

1 1

1 m

ark

for -

60

Allo

w c

onse

quen

tial m

etal

fro

m th

eir c

alcu

late

d A

A

nsw

er h

as g

ot to

be

a m

etal

to

sco

re M

2

Che

mis

try -

AQ

A G

CE

Mar

k S

chem

e 20

09 J

anua

ry s

erie

s

8

Que

stio

n P

art

Sub

Par

t M

arki

ng G

uida

nce

Mar

k C

omm

ents

6 (a

)

Sin

gle

bond

s on

ly /n

o do

uble

or m

ultip

le b

onds

; C

onta

ins

carb

on a

nd h

ydro

gen

only

; A

lkan

es;

1 1 1

C a

nd H

onl

y

not C

and

H m

olec

ules

6 (b

)

(1)

Frac

tions

or h

ydro

carb

ons

or c

ompo

unds

hav

e di

ffere

nt

boili

ng p

oint

s/ s

epar

atio

n de

pend

s on

bp;

(2

) bp

dep

ends

on

size

/ Mr/

chai

n le

ngth

; (3

) Te

mp

grad

ient

in to

wer

or c

olum

n / c

oole

r at t

op o

f col

umn

or v

ice

vers

a;

(4)

Hig

her b

p / l

arge

r or h

eavi

er m

olec

ules

at b

otto

m (o

f co

lum

n) o

r vic

e ve

rsa;

1 1 1 1

Igno

re m

p an

d vd

w

If re

fer t

o bo

nd b

reak

ing/

cr

acki

ng/ b

last

furn

ace/

ox

ygen

/air

2 m

ax

QW

C

Not

incr

easi

ng s

ize

of fr

actio

n N

ot g

ases

at t

op

6 (c

)

Larg

e m

olec

ules

or c

ompo

unds

or l

ong

chai

n hy

droc

arbo

ns

(bro

ken)

into

sm

alle

r mol

ecul

es o

r com

poun

ds o

r sm

alle

r ch

ain

hydr

ocar

bons

; Ze

olite

or a

lum

inos

ilica

te (c

atal

yst);

C

14H

30

C8H

18 +

C6H

12;

Sm

alle

r cha

in m

olec

ules

are

in m

ore

dem

and

or h

ave

high

er

valu

e or

vic

e ve

rsa;

1 1 1 1

QW

C

Onl

y In

suffi

cien

t to

say

mor

e us

eful

/ ha

ve m

ore

uses

6 (d

)

C8H

18 +

8½

O2

8C

O +

9H

2O;

Rh/

Pd/

Pt/l

r or i

n w

ords

; 2C

O +

2N

O

2C

O2 +

N2 /

2C

O +

O2

2C

O2;

Gre

enho

use

gas/

abs

orbs

infra

red

radi

atio

n;

1 1 1 1

Allo

w m

ultip

les

Pen

alis

e co

ntra

dict

ion

of n

ame

and

sym

bol

Allo

w m

ultip

les

Che

mis

try -

AQ

A G

CE

Mar

k S

chem

e 20

09 J

anua

ry s

erie

s

9

6 (e

)

car l

ess

pow

erfu

l/ ca

r sto

ps/ r

educ

ed p

erfo

rman

ce/ w

on’t

run

smoo

thly

/ can

’t ac

cele

rate

; Te

st it

(bef

ore

sale

) /Q

ualit

y co

ntro

l etc

;

1 1

Not

inco

mpl

ete

com

bust

ion

or

bad

effe

ct o

n en

gine

N

ot d

oesn

’t go

as

far.

6 (f)

(com

poun

ds w

ith) s

ame

mol

ecul

ar fo

rmul

a / s

ame

no a

nd ty

pe

of a

tom

s;

And

diff

eren

t stru

ctur

e/ s

truct

ural

form

ula;

2,

2,4-

trim

ethy

lpen

tane

;

1 1 1

Not

ato

ms/

elem

ents

with

sam

e m

olec

ular

form

ula.

If

sam

e ch

emic

al fo

rmul

a, c

an

allo

w M

2 M

2 co

nseq

uent

ial o

n M

1 A

llow

dis

play

ed fo

rmul

a fo

r M2

Onl

y (b

ut a

llow

num

bers

in a

ny

orde

r)