Atomic Structure and Amount of Substance A

8/16/2019 Atomic Structure and Amount of Substance A

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, 1%-& (1) 2

(e) (i) . , 1&-& (1)

B 0 ,&-1%

2-&101

&-1& (1)

, 2 0 0 B2 (1)

(ii) B'1% (1) '

[13]

3. (a)of atom1mass

atomanof massmean12

(1) + 12 (1) 2

(b) 3ultiply by 4vogadros number 1

(c) (i) 3oles a ,2'

1 (1)

moles aO , 3oles a , %-%'15 (1)

, %-165 mol2 dm

! (1)

(allo7 %-166 %-16&)

(ii) p8 , n"9 (1)

,1%%%%%

2:!!1-&%'15-% ××

(1) allo7 conse;uential

, %-%%1%2 m! (1)

(allo7 %-%%1%1 %-%%1%!) (allo7 in dm! or cm

!)

(iii) vol l ,%-112

moles + 1%%% ,

112-%

%%'15-% + 1%%% (1)

, !5-! cm! (1)

(allo7 !5-1 to !&-% and conse;-) &

[11]

4. (a)!'

S (1)

16 (1) 2

(b) 1s2 2s

2 2p

6 (1) 1

(c) not accelerated (1) 1

(d) 1-6 + 1% 2'

(1)

cranford community college 2



121%::!1

1%1&22!

2!

×

×⋅

×⋅ (1) , 12⋅:: (1)

or 6-%2! + 1%2!

+ 2-1& + 1% 2!

, 12-::& (1)

any use of12

<1!

(1)

1%%

111!

1%%

::&12 ⋅×+

⋅× (1)

, 12⋅%1 (1) 6

[10]

5. (a) %⋅2'% (1)

3r (9i1') , 1:% (1)

moles 9i1' ,'

2'% ⋅, %⋅%6 (1)

mass , %⋅%6 + 1:% , 11⋅' (1) '

(b) moles aO , moles l , %-12 (1)

vol aO ,conc

moles (1)

,11

12%

⋅

⋅, 1%:cm

! (1) !

(c) moles 2 ,2

1moles , %⋅%6 (1)

(allow conseq)

V , p

nRT (1) or PV , nRT

,%%%:&

2:!!1&%6% ×⋅×⋅

(1)

, 1⋅': + 1% !

m! (1)etc

(if chemical error on moles 2= ma>2) (2) '

[11]

6. (a) pV , nRT or n = pV/RT or pV , M

m

RT or seen in substituted form (1)

(1) (1) (1)n , PV/RT , 1-% + 1%

+ 5% + 1%

!/ &-!1' + !1! , '-%! (mol) '

(b) (1) (1)




'-%! + 2/! , 2-6: (mol) allo7 e-c-f from (a)

?f ratio !/2= allo7 1 ma>@ for other ratios= give Aero 2

(c) (1) (1)

2-6: + 6 = 152 g (unit re;uired) allo7 e-c-f from (b) 2[8]

7. (a) (i) proportion / ratio / fre;uency / percentage / abundance of each

isotope / different type of atom / specific atom

not amount unless relative amount compared to total amount (1)

present in the (natural) isotopic mi>ture / sample of the

element / compound containing the element (1)

reference to relative atomic mass 7orth Aero mar*s 2

(ii) (%-%&%2 + '6) $ (%-%5!1 + '5) $ (%-5!&1 + '&)

$ (%-%' + ':) $ (%-%!2 + %) (1)

= '5-: (ignore units) (1) 2

(b) (i) total of three pea*s (t7o e>tra pea*s) (1)

in a ratio of 1 0 2 0 1 7ith first pea* at 1& and

middle pea* height !- → '-cm (1)

at positions 1&= 16%= 162 (1)

for 2 pea*s only= allo7 1 mar* if ratio 10 l and 2nd pea* at 162 !

(ii) ! different permutations5:

Br 5:

Br@5:

Br &1

Br @&1

Br &1

Br (1)

(allo7 this mar* for appropriate argument= if 2 pea*s given in (i)) 1

(iii)5:

Br&1

Br statistically t7ice as li*ely as5:

Br5:

Br or&1

B&1

Br /

' possible permutations= 7ith5:

Br&1

Br and&1

Br5:

Br being identical (1)

(dont allo7 this mar* if 2 pea*s given in (i)) 1

(c) ratio al 0 a2O! , 2 0 1 (1)

mass ratio al 0 a2O! , 115 0 1%6 , 1 0 1%6/115 (1)

'6 *g al produces '6 + 1%6/115 (1)

, ': *g a2O! (unit re;uired) (1)

or

moles al , '6%%%/&- , :!!! (if :-!!= allo7 ! ma>) (1)moles aO! , moles al , :!!! (1)

moles a2O! , moles aO! , × :!!! , '665 (1)

mass a2O! , '665 + 1%6 , ': *g (unit re;uired) (1)

or

mass ratio al0 aO! , &- 0 &' (1)

mass aO! , '6 + &'/&- , 5&' *g (1)

mass ratio aO! 0 a2O! , 16& 0 1%6

mass a2O! , 5&' + 1%6/16& (1)

, ': *g (unit re;uired) (1) '




(d) appropriate diagram= 7ith one lone pair and three bonding pairs

for ammonia (1)

appropriate diagram 7ith t7o bonding pairs Coining to each

O in O2 and

t7o lone pairs on each o>ygen (1)

if inner electrons are sho7n they must be correct 2[15]

8. (a) 22-2'/12 , 1-& !-51/1 , !-51 Br 5'-%/5:-: , %-:25 (1)

ratio 00Br , 20'01 ∴2'Br (1)

empirical mass , 1%5-: ∴ mol formula , 21-&/1%5-: + 2'Br , '&Br 2 (1)

must use . to Custify ans7er

or (22-2'/1%%) + 21-& , '5-:: i-e- '&/12 , ' carbon atoms (1)

(!-51/1%%) + 21-& , &-%1 i-e- &/1 , & hydrogen atoms (1)

Br (5'-%/1%%) + 21-& , 1:-& i-e- 1:-&/5:-: , 2 bromine atoms (1)

or

('&/21-&) + 1%% , 22-2'. (1)

(&/21-&) + 1%% , !-51 . (1)

Br (1:-&/21-&) + 1%% , 5'-%. (1) !

(b) any two pairs of marks

1=1DdibromoD(2D)methylpropane (1)

graphical formula to suit (!)2Br 2 (1)

1=2DdibromoD(2D)methylpropane (1)

graphical formula to suit (!)2(Br)2Br (1)

1=!DdibromoD(2)Dmethylpropane (1)

graphical formula to suit Br2(!)2Br (1)

allo7 unambiguous names

mar* name and structure independently

accept order of bromo / methyl reversed

penalise once for each of

numbering from 7rong end and di in dibromo omitted ma> '




(c) (i) alcoholic/ethanolic solution (not Cust alcohol must be solvent) (1)

structure to suit !,2 (1) 2

(ii) a;ueous solution (not 7ater alone= unless solvent penalised in (i)) (1)

structure to suit !(O)! (1) 2

(d) (i) cyanide ion /

/

not nitrile ion (1) 1

(ii) nucleophilic substitution / S ? / S 2 (1) 1

(iii) !(Br)! $ → !()! $ Br / ionic version (1)

(condone missing brac*ets) 1

(iv) structure to suit !()! (7ith bond sho7n as a

triple bond) (1)

1[15]

9. (a) mean mass of an entity (or molecule) (1) + 12 (1)

mass of 1 atom of12

2

(b)2! 1%::!-1

12

×

, 6-%2 + 1%2! (1)

(allo7 6-%2% to 6-%2!) 1

(c) (i) charge (1)

(ii) 3g?2 $ 2FE!$

→ 3g2$

$ ?2 $ 2Fe2$

(1) 2

(d) (i)8

"9n P = (or p8 , n"9) (1)

:%%%15

1%1! !

=×

==

Mr

massn

(1)

!&%%!1-&:%%%

××= P

(1)

, 1-:: + 1%5 Pa (1) (allo7 1-:: to 2-%%)




(ii) 1-:: + 1%5 +

&%%

1%%% , 2-': + 1%

5 Pa (1)

(allo7 conse;)

(iii)1%%%:%%%

, :-% mol dm ! (or 3)

(1) (1) 5[12]

10. (a) protons mass $1 charge $ (1)

neutrons mass $1 charge Aero (1)

electrons mass Aero (orG1/1&%%)= charge (1)

nitrogen 1' has a nucleus 7ith 5 protons and 5 neutrons (1)

surrounded by electrons in shells (or orbitals) (or 2=) (1)

7ith configuration 1s2 2s

22p

! (scores last 2 mar*s) (1) 6

(b) isotopes have the same atomic number (or same number of protons

or same element) (1)

but different number of neutrons (or mass number) (1) 2

(c) sample introduced at lo7 pressure (or gas or vapour or vacuum) (1)

electron gun (or bombarded 7ith electrons) (1)

7hich *noc*s out an electron (or removes an electron) (1)

producing a positive ion (1)

the ions are accelerated (1)

and focused (or made into a beam) (1)

by an electric field (or negative plates or electric plates) (1)

magnetic field (or magnet) (1)

ions are deflected (1)

deflection depends on m/z of each ion (1)

lightest (or smallest m/A) deflected most (1)

ions go to a detector (1)

a small current is produced (or abundance counted) (1)

7hich is fed to a computer (or recorder or display or chart etc) (1)

electric field (or magnet) adCusted to collect ions of different mass (1)

ote0 a picture of a spectrum can score the chart mar* and the

abundance mar* (if the Hya>is is labelled Habundance or H.- ma> 1'

(d) fraction of each component is rel- int-/'' (1)

Ithe mar* is for ''= if '2 ma> 1J

relative atomic mass

, 1 + &%/'' $ + &2/''$ + &!/'' $ 2 + &'/'' $ & + &6/'' (1)

, &!-: (1)

rypton (1) '




(e) percentage by mass of o>ygen , !&-%. (1)

ratio of elements , '2-:/12 0 2-'/1 0 16-5/1' 0 !&-%/16 (1)

, !-6 0 2-' 0 1-2 0 2-'

empirical formula is !2 O2 (1)

molecular formula is 6' 2O' (1) '

[30]

11. (a) simplest ratio of atoms of each element in a compound (1) 1

(b) mass of O , 1-&'2 g (1)

a 0 0 O ,'%

56:-%01'

!:-%0

16

&'2-1 (1)

, 10206a2O6 (1) !

(c) 3r (1) 1

(d) (i) n ,"9

#8 (1) (allo7 #8 , n"9)

, 2:!!1-&

1%!-11%: ! !

×

×××

(1)

, %-%:5 (1) (allo7 %-%: to %-%6)

(ii) %-%:5 +' , %-2!: (1) (allo7 %-2')

(allo7 conse; on (i))

(iii) moles ! , %-2:! +1%%%

2 , %-%%:5 (1)

volume , 1%%% +1-%

%%:5-% , !:-& (cm

!) (1)

(allo7 conse;

allo7 %-%!:& dm!) 6

[11]




12. (a) mass number , number of protons $ neutrons in an atom

(or a nucleus or an isotope) (1)

(allo7 number of nucleons)

atomic number , number of protons in an atom (1)

e>ample of an isotope 7ith mass number and atomic number

and symbol or name (1)!

(b) (i) ?onisation (1)

7ith an electron gun (1) (or stream of electrons or high energy electrons)

7hich *noc*s out an electron from an atom or molecule (1)

producing a positive ion (1) (note this also scores ionisation mar*)

(note 3 $ e

→ 3$ $ e

$ e

scores first= third and last of these mar*s)

(ote that if ion not mentioned or negative ion used ma> ! for ne>t :mar*s= if electron E,%)

4cceleration (1)

7ith an electric field (1) (or charged plate)

Keflection (1)

in a magnetic field (1) (or magnet)

depending on mass/charge (or m/ z ) ratio of ion (1)

particles 7ith least m/ z (or least mass) deflected most (1) (or converse)

Ketection (1)

?on falls on Hcollector producing a current (1) (or electrically

detected or falls on a ve plate)

fed into computer for analysis (1) (or displayed on a graph) 3a> 12

(ii) use mass/charge (m/z ) data (1)

and relative abundance (1) (or pea* height or intensity)

Ar , (abundance of isotope + mass)/sum of all abundances (1)

(can gain abundance mar* here)

added together for all isotopes (1) '

(c) ionisation energy decreases do7n group (1)

outer electrons more shielded (1) (or further a7ay)

ionisation energy sho7s general increase across a period (1) (overall

decrease loses ! mar*s)

nuclear charge increases (1) (or number of protons)

electrons in same shell (1) (or similar shielding)




decrease from 3g to 4l (1)

outer electron in 3g is (!)s= in 4l is (!)p orbital (1) (2s or 2p loses

this mar*) outer electron (or electron removed) from 4l is in higher

energy level (1)

decrease from # to S (1)

last electron in S is paired in a (!)p orbital (1) (2p loses mar*)

repulsion bet7een electrons in pair (1) 11

(?f use Li to e= use same mar* scheme 7ith 2s= 2p but ma> 5 out of :)[30]

13. (a) p V , nRT or e;uivalent (eg rearranged or substituted) (1)

conversion of volume units (to '-6% + 1% 6

m!

) (or dm!

7ith pressure in *#a) (1)

conversion of temperature units (to 1'5! ) (1)

correct ans7er (%-%!6g to %-%!5 g) (1) '

allo7 2D sig-figs

condone missing unit@ penalise 7rong unit

allo7 e-c-f- for incorrect conversions

(b) calculation of ? . (&) (1)

division of . by 4r values

correct ans7er (M?2) or appropriate ans7er for their ratio (1)

ans7er must be a formula

if 7rong Hatomic mass used in !(a) and (b)= penalise once only ![7]

14. (a) (i) A , electron= B = neutron and , proton a!! correctly identified (1)

do not give if any reference to cation / anion 1

(ii) neutron / n% / B has no charge and so is undeflected (1)

proton / p$ / and electron / e

/ A attracted to ve and $ve plates

respectively (1)

correct direction and shape for one particle gains one mar*

mass p N mass e

so deflected less / mass N mass A so deflected less (1)

allo7 this mar* for valid difference in property and e>planation of shape

allo7 reference to other particles here !




(b) (i) to produce high speed electrons / stream of electrons or to fire electrons or

to bombard 7ith electrons or is an electron gun (1)

7hich remove electrons from species cause formation of positive ions

not to ionise (1) 2

(ii) to accelerate / speed up positive ions / ions / fragments (1)not electrons atoms / molecule / sample

allo7 particles / molecular ion

to deflect / bend ions / ion stream (not to provide magnetic field)

or separate ions accordingly to mass / charge ratio (1)

to detect positive ions / ions / particles / fragments / molecular ion (1)

allo7 purpose of specific detector or ion detector

not Cust detector or collector

allo7 second and third mar*s if 7rong type of particle given !

(c) the volume / space occupied by 1 mol of (any) gas /

4vogadro number of molecules (1)

at given temperature and pressure (1)

allo7 one mar* if specific temperature and pressure ;uoted

second mar* is dependent on first mar* 2

(d) (i) mass ratio of O20lO! , :6 / 2'-2 ( , %-!:2)

or moles of O2 , !/2 + 1-2% + 1% 2

or e;uivalent (1)

mass of O2 = %-!:2 + 1-'5 , %-56g (1) 2

(ii) moles O2 = 1-%%/2'-%% ( , %-%'15 mol) (1)

moles lO! , 2/! moles O2 , %-%'15 + 2/! , (%-%25& mol) (1)

mass lO! , %-%25& + 122-6 , !-'lg (1) !

give one mar* for pV , nRT to get n for O2=

then second and third mar* as aboveor 2/! mole of lO! → 1 3ole of O2 (1)

&1-5g → 2' dm! O2 (1)

2'5-&1

g , !-'lg → 1 dm! O2 (1)

penalise other than 2 sig- figs- once in (d)(i) and (ii)

penalise missing or 7rong units once in (d)(i) and (ii)[16]




15. (a) electron gun (1) 1

(b) accelerated (1) 1

(c) speed (1) 1

(d) "1#"1#:

2&6&'1&!1&2 ×+×+×+×

, &'-1 (1) ![6]

16.(a) 3ass of each element in the compound (1) 1

(b) umber of atoms of each element in a molecule (1) 1

(c) 12of atomanof mass

atomanof mass3ean12

×(1)

(1) 2

(d) (i) 3r Ba(O!)2 , 261 (1)

moles Ba(O!)2 ,261

(1) , %-%1:2

moles gas , 2 21 + %-%1:2 (1) , %-%'5:

8 ,

p

n"9 (1) ,

1%%%%%

2:&!1-&%'5:-% ××

, 1-1: +1% !

m! (1)

(ii) moles l , 2 + %-%1:2 (1) , %-%!&'

vol l ,2-1

%!&'-% , %-%!2 dm

! (1) (or !2 cm

!) 5

[11]

17. (a) First ionisation energy equation Li(g) → Li$(g) $ e (1)

Secon ionisation energy equation Li$(g) → Li

2$(g) e

(1)

tate symbols (1) !

(b) (i) es electron in 1s (1)

closer to nucleus (or no shielding) (1)

(or converse argument for Li)

(ii) Bes outer electron in 2s (1)

lo7er in energy than 2p (1)

(iii) Electron removed from positive ion (1)

7hich attracts the electron more (1)




(allo7 for 2nd

electron nearer to the nucleus) 6[9]

18. (a) Relati!e mass 1 (1)

Relati!e c"arge % (1) 2

(b) #n common number of protons (or electrons) (1)

$i%%erence number of neutrons (1) 2

(c) '11: (1) (1) 2

(d) (i) Measurement 1 3/ (1)

Measurement 2 relative abundance (1)

(ii) charged (or negatibe) plate

creates a current 7hen hit by ion

sends a signal to a computer (or chart recorder)any 2 points

(iii) same 3/ (1)

(e)

1 s

2 s2 s

6 e l e c t r o n sc o r r e c t a r r a n g e m e n t

( 1 )( 1 )

6 electrons (1)

correct arrangement (1) 2

(f) 1s2

2s2

(1) 1[14]

19. (a)J1II1%::-1

122!

× , 6-%!+1%2! (1) 2




(b) simplete ratio of atoms of each element in a compound (1) 1

(c)

of atomoneof mass

entityPof massaverage12 (1) + 12 (1)

(or definition in terms of moles) 2

(d) O , 2:2:

15' , 6 (1)

∴ 6 6 O6 (1) 2

(e) 'O$

2

! O2 → O2$22O (1) 1

[8]

20. (a) moles of ! ,%-15

%-2% (1)

moles of K! , moles of ! , 1-1&

volume ,2

1&-1 (1)

, %-&& (1) dm! (1) '

(b) (i) #8 , n"9 (1)

n ,"9

#8 ,

2:&!1-&

%%%-%:%%%

×

× (1)

, 1-:2 mol (1)

(ii) Moles o% ammonium nitrate -1

:2-1(1) 1-2& mol

Mass o% ammonium nitrate mass , 1-2& + &% (1) , 1%2 g (1) 6[10]

21. (a) umber of protons < number of neutrons (1) 1

(b)

1 5

&

( 1 )

O ( 1 )2




(c) (i)

#article proton neutron electron

3ass /g 1-652 + 1% 2'

1-65'& + 1% 2'

%-%%%: + 1% 2'

"elative charge +1 0 –1

(ii) 1-65!' + 1% 2'

g (1)

(iii) 1-%%5& g (1)

(iv) other isotopes present (1) '

(d) (i) electric field (or charged plate) (1)

(ii) magnet (1)

(iii) different isotopes (1)

(or different masses)

(iv) accelerate ions more

(or reduce magnetic field) (1)

(v) Measurement 1 z m (1)

Measurement 2 abundance (1) 6

[13]

22. (a)of atom1of mass

entityanof massaverage

12

(1) + 12 (1) 2

(b) simplest ratio of atoms of each element in a compound 1

(c) (i) .O , 6-5 (1)

00O ,16

5-60

1

'%-10

12

:-!2 (1)

, 1-:60 1 0 2-:!

, 2 O! (1)

(ii) ' 2 O6 (1) '




(d) (i)

(1)

16

1%%%

3

mass

r

=

, 62- (1)

&'&(2) scores one

(ii) p8, n"9 (1)

8 ,

1%%%%%

2:&!1-&-622 ×××=

P

nRT

(1)

(1)

, !-1 % m ! (1)

*allow consequential mar+ing ,ut i% %actor o% 2 in missing ma- = 2. 6[13]

23. (a) (umber of) protons or and $ (number of) neutrons (1) E mass of p 2

(number of) protons (1)

Allow no' o% nucleons / amount o% p n'ignore additional comment about electrons butpenalise ‘ electrons!

2

(b) :

1B (1)

(1)

*allow 0oron in wors. penalise '&

2

(c) 1s2 2s

2 2p

! (1)

1s2 2s

2 2p

6 (1)

i" use [#$% 2p3 penalise once

allow 2p - 2p y etc

2p4 2p

2

i" omit 2 in 2p penalise once




(d)of atom1of)(mass

I1Jatomanof massaverage)(or mean

12 + 12 (1)

molecule& element& entity % instead o" atom loses 1st

mar'

oratomsof mol1of mass

I1Jatomsof mol1of mass12

+ 12 (1)

or mean mass of an atom Qcompared 7ith= relative to Qan

atom of12

ta*en as 12=12

1 of a

12 atom 2

(e) (i) electrons from electron gun (1)

or Qhigh speed electrons beam of electrons= bombarded

7ith es= O9 electric gun=

*noc* out electron from R (1)

or Q + $ e → +$ $ 2e= idea of loss of es

(ii) Qalter (or change= or vary) magnetic= (or electric) field

(or accelerating potential) (1)

(ii)J1I1 :(1%

J1I)&62()&'6()&!1()&21(

At 2 or i%

×+×+×+×

(treat one )rong multiplicand as *$ +1& 2 mista'es ,$-

, &'⋅1 (1)

(ignore units-

(iv) r (1)

*allow conseq. 5[15]

24. (a) 4vogadros 1

(b) (i) p8,n"9 (1)

allow 3V= P

nRT etc'4 pV=

Mr

m RT




(ii) 8, P

nRT

,%%%1%%

2:&!1&1 ×⋅×

(1)

, %-%2'& m! (1)

*allow &'&256 to &'&2).

allow use o% 1&& %or P i% ans gi!en as 25'7 m8

(iii) n,"9

p8 ,

25!!1-&

%%-%%%%%%

×

× (1)

(treat 500 as *$+1 ot.er /alues ls 2mar

00051000 loses 1st

t)o mar's

, 1-1%mol (1)

*allow 1'1 to 1'11.

3r (O2) , '' (1)treat )rong r as *$+1

mass , ''+1-1% , '&- (g) (1)

*allow 5795.

(note can use calculation in/ol/ing

T

V P 11 and 224 dm

3 instead o" 1

st mar'

reuires same accuracy "or "ull mar's-

5

(c) moles 1 ,1%%%

1%% + -% , %-(%)(mol) (1)

moles 2 ,2

1moles (1) , %-2 (mol)

(i" no "actor o" 2 ,$ "rom .ere-

mass 2 , %-2+2 , %-(%) (g) (1) !




(d) (i) %O , ''-' (1)

(i" incorrect & *$+1-

(i" omitted can score ma 1 "or e,2-

ratio e, &-:-!&

(or 50-

%-12

5-16

%-16'-'' (i" use *t& ,$-

, 1 0 2 0 '

Fe 2 O' (1)

(ii) O (1)(mar' independent o" d (ii--

'[15]

25. pV = nRT (1)

moles l2F2 , (1+1%6 + 1 +1%

6) / 121

(, &-26 + 1%: mol) (1)

V , (&-26 + 1%: + &-!1' + 2:&) / 1-%1 + 1%

(1)

V , 2-%! + 1%&

m!

2 + 1%&

or any no- sig- fig- (1) '

penalise 7rong units

ans7er must be correct for their figures[4]

26. (a) number of protons (1) 1

(b) different number of neutrons (1)

t"ey are :isotopes; 9 not enoug" %or t"e mar+ 1




(c) (i) mass spectrometer (1)

allow spectroscope

(ii) (or average)

1 2

m e a n

a t o m

m a s s o f a n a t o m

( m a s s ) 1 o f + 1 2 ( 1 )

( 1 )

or (1)(1)

12atomsof mol1of mass

atomsof mol1of mass12

×

or mean mass of an atom (1)

or compared 7ith Qan atom of12

ta*en as 12

Q 121 of a

12 atom

#% molecule4 element or entity instea o% :atom; lose 1 mar+ 1

(iii)1%%

)26&6()%&'()12&!()12&2( ×+×+×+×

(1) , &'-16 (1)

allow 75'1 to 75'2 ignore units

(d)1 s 2 s 2 p ! s ! p ' s ! d ' p ( 1 )2 2 2 26 6 61 %

not allow <Ar

(e) more protons (1)

or increase nuclear c"arge

attracting electrons in the same Qshell

Qorbital

Qsubshell

Qenergy level

or similar s"ieling 2

(f) outer electron in "b is in th shell (or additional shell) (1)

further a7ay (or more shielded) from nucleus (1)

mar+ inepenently ,ut i% t"ere is contraiction 9 no mar+s 2[12]




27. (a) 4vogadros number of molecules (1)

allow ( to ('1 > 1&28

molecules ?R @o' o% atoms in 12g o%12

1

(b) (i)

61

1%%=

r M

mass

(1) , 1-6'(1)

allow 1'(8 to 1'(5

#8 , n"9 (1)

8 ,%%%1%%

'%%!1-&6'-1! ×××=

P

nRT (1) if no + ! E

allow use o% p = 1&& i% answer in m8

, % - 1 6 ' m!

(1)

allow &'1(2 to &'1(( allow conseq on moles 2 @?2

(ii) 8 , 81 +'%%

1%%%16'-%

1

2×=

T

T (1)

allow conseq on !ol o% gas proucts in *i.

, %-'1% (m!) (1)

allow &'5 to &'52

or%%%1%%

1%%%!1-&6'-1!

#

n"98

×××== (1) or (for 1

st mar*)

T"us i% ans = ans to *i. >'

1%allow 2 mar+s ignore units

allow conseq on moles 8 @?2 an on omission o% 8 5

(c) moles O2 , moles a2O! , %''-%''

2= (1)

allow &'&5) to &'&5(

moles in 1%%% cm! , %-%'' + , %-225 (mol dm

!) (1)

allow &'22 to &'28

2n

mar+ allow conseq moles *%rom %irst melting point. > )

units not essential4 penalise wrong units *1 mar+. 2




(d) . % , 1%% 2-: , 5'-1 (1)

wrong B AC 91

0 O ,16

1-5'0

1'

:-2 (1)

, 1 0 2-

∴ 2O (1)

@?8 gains %irst two mar+s pro,a,ly !

(e) 2O → 2O2 $2

1 O2 (1)

allow > 2

if (d) is O!

allo7 O! → O2 $2

1 O2

or > 21[14]

28. (a) number of protons in one atom or nucleus (1)*llo) protons : electronsdo not allo) protons electrons or electrons

1

(b) 2!11 (1) a (1)

; <a 23

11 or <a (1- unambiguous statement o" mass no and

atomic no

2

(c) 1s2 2s2 2p6 !s2 !p1 (1)

*llo) <e 3s2 3p

1

1

(d) 1' (1) 1




(e)ofatom1of mass

isotope)(oratomanof massaverage12

(1) + 12 (1)

;e"erence to mass number not mass ,$ 0; stated in moles

; compared )it. 112 o" a

12

, atom or relati/eto

12, ).en ta'en as 12

2

(f) (i) electron gun (1)

(ii) (particles must be charged) (ions) before attraction to a charged plate (or electric

field) (1)

(or only ions can be attracted or accelerated by an electric field)

or con/erse= i" not c.arge not attracted to electric "ield

(iii) magnetic field (or magnet) (1)

(iv) magnetic field (1) (accelerating potential or strength of magnet)allo) magnet

'

(g) (i)(1)1%%

-1%-26!-2%%-22-6'%-2' ×+×+×

(1) mar* for any m/A + relative abundance>" numerator is correct but 100 .as *$ conse *$ 1>" *$ on 100 allo) conse correct ans)er pro/ided numerator is correct

, 2'- (1)

*llo) 245 to 2452ignore units

(ii) magnesium (1) (or 3g) (allo7 conse; on 7rong 4r )

(iii) abundance of isotopes is different (1) (or $iff%r%nt isotop%s) [16]




29. moles aO used , vol / 1%%% + (1) , 21-7 (i" uses 25 .ere only scores

"irst o" "irst 4 mar's-/ 1%%% + %-112

, %-%%2'! (1) (consider %-%%2' as an arithmetic

error loses 1 mar*)(range 000242 to 000244-

moles l in 2 cm! , %-%%2'! (1) (or 1 mol l reacts 7ith 1 mol aO)

moles of l in 2% cm!

, %-%2'! (1)

moles l' , %-%2'! / ' , %-%%6%5 (1) (or %-%%6%56 or %-%%6 mar* is for / ')

M r , mass / no- 3oles (1) (method mar* also 1-!%' / %-%%6%5)

, 21'-5 (1) (or %-%%6 gives 215) (a!!ow 214 to 215)

Ar , 21'-5 D 1'2 , 52-5 (1) (215 gives 5= 1'2 is !- + ')

9herefore element is ermanium (1) (allo7 conse; correct from Ar )

(75 gi/es *s-

>" not 4 ,$ "rom t.ere on but can score 2 independent mar's "or (mass

moles met.od and identity o" element-

("or candidates ).o use m1/1 m2/2 and calculate [#,l] 00972 allo) 1st

3

mar'si" 25 and 217 )rong )ay round only a)ard 13-

[9]

30. (a) L ,2'1%65!'-1

%%5&-1−

×

(1) oratom1of mass

mol1of mass

must s.o) )or'ing

, 6-%22 + 1%2!

(1)>gnore )rong units

<? ans)er only scores 1

2

(b) e;ual (1)r same or 11

1




(c) #8 , n"9 (or n , RT

PV ) (1)

,2:&!1-&

%!2-%:&%%%

×

×

(1)

, 1-!: (1)*llo) 1390 to 1395

ignore units e/en i" incorrect

ans)er 14 loses last mar'

!

(d) %-5!2 +2%

1%%% , 2-:! (1) mol-dm

! (1)

; & moldm3& moll +1

allo) 2928 to 293

<ote unit mar' tied to current ans)er but allo) unitmar' i" ans)er 29 or 3

2

(e) (i) moles 2SO' ,1%%%

2 + 1-2' , %-%!1%

>" use m1/1 m2/2 scores 3 i" ans)er is correct ot.er)ise @ero

moles ! in !%-& cm! , %-%!1% + 2 , %-%62% (1)

ar' is "or A2

,$ i" A 2 not used

moles of ! in 1 dm! , %-62% +

&-!%

1%%% , 2-%1 (1) (mol dm

!)

*llo) 2010 to 2015

<o units B& )rong units lose last mar'




(ii) moles (')SO' , moles 2SO' , %-!1% (1)

*llo) conseuential )rong moles in part (i- i" clear #2C4(<#4-C4

Drong "ormula "or (<#4-C4 ,$0

3r (')SO' , 1!2-1 (1)*llo) (132-

mass , moles + 3r , %-%!1% + 1!2-1 , '-1% (1)

if mo!%s of (&'4)4 not *!%ar +

(g- )rong unit loses mar'

*llo) 409 + 41 + 411

6

(f) 3g! 2 $ 62O → !3g(O)2 $ 2!

ormulae (1-

?alanced euation (1-

2[16]

31. (a) #roton0 mass 1= charge $ 1 (1)

eutron0 mass 1= charge % (1)

Electron 1/1&'%= charge D1 (1)*llo) mass 0& or negligible& or 11800 to 12000

?sotopes have the same number of protons (1); atomic number

different number of neutrons (1)

?sotopes have the same electronic configuration (1); same number o" electrons

hemical properties depend on electrons 5

(b)of atom1of mass

pesatom/isotoanof massaverage12

(1) +12 (1)

;,o" atom1o" mass

atomso" mol1o" mass

12 A 12 or in )ords

Spectrum gives (relative) abundance (1); E or amount




4nd m/z (1)

3ultiply m/z by relative abundance for each isotope (1)*llo) instead o" m@ mass no& *r or actual /alue "rom eample

Sum these values (1)

Kivide by the sum of the relative abundances (1)only a)ard t.is mar' i" pre/ious 2 gi/en

a 2 i" eg .as only 2 isotopes 7

[14]

32. (a) 3oles l ,r 3

mass ,!6-

1:-6 (1) (, %-!5)

oncentration , 2-%

!5-%

(1)

, 2-1 (mol dm !

) (1)

,onse onr 3

mass correct

min 2 dp 214 to 215>gnore units*$ lose one mar'

!

(b) (i) 26!-%1%%%

5-21× , -5(1) + 1%

! (mol) (1)

57 to 571 A 10 +3

(ii)2

1%51-!−

× , 2-& + 1%

! (mol) (1)

,onse

(iii)!1%&-2

!:'-%−

× , 1!& (1)

,onse




(iv) Relati!e atomic mass o% M 0 1!& D 6% , 5& (1)

2

5& = !: (1)

#enti%y o% M 0 #otassium or or $ (1)

,onse>" 78 r t.en selenium

6[9]

33. (a) ?deal gas e;uation la7 (1) 1

(b) Moles o% X 0 RT

PV n = (1) = '5!!1-&

1%!'-211%%%% '

×

×× −

, 6- + 1% !

(1)

65 to 66 A 10 +3

& min 2 sig "igs

>" )rite PV

RT n = @ero .ere& but can score r

Relati!e molecular mass o% X 0 3r ,n

m (1)

, 62 (1)615 to 625

'

(c) . o>ygen , 1-6 (2)

,!&-5 / 12 , :-6& / 1 O , 5-6(2) / 16 (1)

, !-2! , :-6& , !-2!

1 0 !0 1 ∴ !O (1)

>" no E or i" )rong *r used t.en ma 1

,orrect empirical "ormula earns all t.ree mar's

!

(d) (!1

62 + !O) , 26O2 (1) 1

[9]




34. (a) ?onisation (1)

igh speed or high energy electrons or electron gun (1)<F bombard<F beam or stream o" electrons

noc*s out (outer) electron (1)

Forming positive ion D could be from 9i → 9i$ $ e

(1)

*ccept ion later in uestion to clari"y c.arge o" ion

Fi e +

Fi 2 e

+ )ort. 2 mar's

>gnore state symbols

4cceleration (1)

By electric field or attraction to negative plate or electrostatic attraction (1)<F repelled by plate

*llo) passed t.roug. positi/e : negati/e plates oppositelyc.arged plates<ot Gust c.arged plates

Keflection (1)

By magnetic field or magnet or electromagnet (1)

Ketection (1)

?dea that ions collected at detector and generate current (1)

Both ions have the same m / A value (of 2') or valid arguments

in terms of the doubled charge on '&9i2$ e>actly counteracting its

doubled mass (1)

Keflected e;ually (so detected together) or deflection dependent

on m / A value (1),an!t get t.is "rom pre/ious section

1%

(b) Kiffer in mass number or number of neutrons (1)

Same proton / atomic number (1)

>gnore re"erence to electrons .ere

?sotopes have the same chemical properties (1)

because all have the same electron configuration or number of electrons

or same number of valence electrons (so no chemical difference) (1)F.is mar' is tied to t.e abo/e mar' or near miss [similar etc] in 3

'




(c) 3ean mass of an atom or (isotope) (1) IO9 mass of average atomJ

"elative to 1/12 mass of12

atom atc- r to12

ta*en as 12-%%% or

e>actly 12 (1)>sotope can be accepted

;ofatomanof massatomanof mass(average)mean

12 (1- A 12 (1-

;of mol1of mass

atomsof mol1of mass12 (1- A 12 (1-

Ar , ('6 + -%&%2) $ ('5 + -%5!1) $ ('& + -5!&1) $ (': + -%') $ (% + -%!2) (1)

, '5-:! ans7er to 2 d-p (1)4792 is acceptableust be 5 sets o" /alues>gnore transcription errors ?HF I<!F ignore missing 100 ,$>" missing isotope ,$

'[18]

35. (a) "elative charge 1 (1)

"elative mass ≤ 1/1&%% or ≤ - × 1% '

(1) 2

Accept zero / negligi,le

(b) (i) #rotons , 2' (1)

(ii) eutrons , 2& (1)

(iii) eed (relative) abundance or pea* height or intensity

/ amount / number / . / fraction of each element (1) !

@otD :ratio o% eac" isotope;

(c) (i) Reason 1D 9o allo7 particles to be accelerated / deflected /

detected or to count

Reason 2D harged particles or to generate a current in the detector

Any 2 (2) @otD :to allow m/z to ,e measure;

(ii) 3agnetic field or electric field or electromagnet (1)

(iii) Keflection depends on mass or m/A (1) '




(d) (i) (simplest) ratio of atoms of each element in compound (1)

(ii) . o>ygen , !:-. (1)

a 2&-'/2! r !2-1/2 O !:-/16 (1)

, 1-2! , %-615 , 2-'5

(2010') so empirical formula , a2rO' (1) ' #% B o-ygen not calculate4 only M2 a!aila,leE i% Ar !alues

wrong4 only M1 a!aila,le

[13]

36. (a) (i) 4toms 7ith the same number of protons / proton number (1)

@?T same atomic num,er

7ith different numbers of neutrons (1)

NOT i%%erent mass num,er / %ewer neutrons

(ii) hemical properties depend on the number or amount of (outer) electrons (1)

O"= isotopes have the same electron configuration / same number of e

(iii) 2!/6-%2! + 1%2!

(1)

C = & i% in!erte or multiplie

tied to 31 !-&(2) + 1% 2!

I2D sig figsJ (1)

(b) 1s2 2s

2 2p

6 !s

1 (1) 1

accept su,scripte %igures

(c) ighest energy e

/ outer e

s / last e

in (!)d subDshell (1) 1

?R su,s"ell ,eing %ille / is incomplete

?R "ig"est energy su,s"ell is *8.

@?T transition element / e 9

con%iguration ens at 8

G o% H

(d)

1

5 correct symbol (1)

allow 15

3ass number , 1 4K atomic number , 5 (1) 2[9]




37. (a) igh speed electrons O" electrons from an electron gun (1)

noc*s out an (outerDshell) electron (on the chromium atom) (1) 2

Accept r*g. I e 9

→ r I*g. I 2e

9

@?T e 9

gun alone / ,eam o% e 9

/ ,om,arment wit" e 9

(b) Electric field O" (attraction to) Dve plate O" electrostatic attraction (1) 1

O" (repelled by) $ve plate O" charged plate

@?T "ig" p'' / electromagnetic %iel / electric plates

(c) 3agnet O" magnetic field O" electromagnet(1) 1

(d) Ar , (% + %-%'!) $ (2 + %-&!&) $ (! + %-%:) $ (' + %-%2') (1)

2-%6 O" 2-% (1) 2

Mar+ consequentially on transcription4 or aition o% B4 error

[6]

38. (a) (i) 5-% + 1% !

+ %-%% , %-%!5 (mol) (1)

accept &'&86 or &'&87

(ii) 21-6 + 1% !

+ %-%% , %-%1%& (mol) (1)

accept &'&11 #% ,ot" *i. an *ii. answers wrong4 allow ?@C process mar+ %or

,ot" correct processes

(iii) %-%!5 D %-%1%& , %-%265 (mol) (1)

@ot conseq 9 must use %igures s"own




(iv) Moles o% Mg?8 , %-%265/2 , %-%1!! (mol) (1)

allow &'&185 &'&188

Mass o% Mg?8 , %-%1!! + &'-! (1)

allow 75

mar+ conseq on moles Mg?8

, 1-12g (1)

accept 1'18g

mar+ conseq

Percentage Mg?8 , 1-12/1-2 + 1%% (1)

mar+ conseq *c"ec+ %or in!ersion.

, :%. (1) &

mar+ conseq

range , &:- D :%-. #% B e-pression in!erte4 lose M5 an M)

(b) (i) . o>ygen , !&-% (1)

a , !6-/2! S , 2-/!2(-1) O , !&-%/16 (1)

, 1-&5 , %-5:' , 2-!5

, 2010! (1)

#% no B o% o-ygen Ma- 1 *allow M2 only.

#% B %or @a an S transpose4 or atomic num,ers use4 M1 only

a!aila,le

(ii) a2SO! $ 2l → 2al $ 2O $ SO2 (1) '

allow multiples

allow S?829

I 2 I → 2? I S?2

[12]




39. #eal gas equation0 p8 , n"9 (1)

alculation0 n , p8/"9 ,)'1!1-&(

1%1251%!%%% 6

×

×× −

(1)

mar+ %or !olume con!ersion %ully correct

, !-5: + 1% !

(mol) (1)

range 8'6 > 1& 98

to 8'7 > 1& 98

3r , m/n , -!%'/!-5: + 1% !

, &%-1 (1)

range 7& 9 7&'8

min 2 s'%' conseq

#% :V; wrong lose M2E :p; wrong lose M8E :in!erte; lose M8

an M5

[5]

40. (a) #roton mass , 1 charge , $1 1

Electron mass ≤ 1/1&%% Or ≤ -6 + 1% '

charge , 1

*$o not accept I1 %or proton mass or :g; units. 1

(b) (i) 1! 1

(ii) Si 1

3ass number , 2& an$ atomic number , 1' 1

*$o not accept 27'1 or 27'& or :Silicon;.

(c) 3ean (average) mass of an atom / all the isotopes 1

1/12th

mass of atom of12

1

Or 3ass of 1 mole of atoms of an element (1)

1/12th

mass of 1 mole of12

(1)

Or 4verage mass of an atom / all the isotopes (1)

relative to the mass of a12

atom ta*en as e>actly 12 / 12-%%% (1)

*Penalise :weig"t; once only. *#gnore :a!erage; mass o%12

.

*$o not allow :mass o% a!erage atom;.




(d) 4r , (2' + %-5!) $ (2 + %-1%1) $ (26 + %-16') 1

, 2'-' 1

*mar+ M2 conseq on transcription error or incorrect aition

o% B.

(e) 3r , highest m/A value 1*@?T :"ig"est/largest/rig"t"an; pea+.

[10]

41. (a) (i) '-&6 + 1% !

1

(ii) 2-'! + 1% !

1

*mar+ conseq on *a.*i..

(iii) 2-'! + 1% 2

1*mar+ conseq on *a.*ii..

(iv) !-%1/2-'! + 1% 2

1

*mar+ conseq on *a.*iii..

12' 1

*$o not allow 125 wit"out e!ience o% appropriate calculation

in *a.*iii..

(b) 3r (a2O!) , 1%6 1

3r ( -2O) , 2% 1%6 , 1'' *mar+ conseq on M1. 1 - , & *mar+ conseq on M2. 1

*Penalise s% errors once only.

(c) (i) #8 , n"9 1

(ii) 3oles 4r , !2/!:-: , &-1 1

*accept M r = 5&.

# , n"9/8 , (&-1 + &-!1 + 2:&)/-%% + 1% !

1

, '-%! + 1%6 #a or , '-%! + 1%

! *#a 1

Range = 5'&2 > 1&( Pa to 5'&5 > 1&

( Pa

*#% equation incorrectly rearrange4 M8 M5 = & #% n =82)4

lose M2.

*Allow M1 i% gas law in *ii. i% not gi!en in *i..

[12]




42. (a) Enthalpy change/re;uired 7hen an electron is removed/*noc*ed 1

out/displaced (?gnore Hminimum energy)

From a gaseous atom 1

*coul get t"is mar+ %rom equation.

(b) 3g$(g) → 3g

2$(g) $ e

E;uation 1

r 3g$(g) $ e

→ 3g

2$(g) $ 2e

State symbols (Tie to M1) 1

(c) ?ncreased/stronger nuclear charge or more protons 1

Smaller atom or electrons enter the same shell or same/similar shielding 1

(d) Electron removed from a shell of lo7er energy or smaller atom or e

nearer 1

nucleus or e removed from 2p rather than from !sLess shielding 1

*$o not accept :e 9

%rom inner s"ell;.

[8]

43. (a) (i) p $ n / number of nucleons *accept protons an neutrons. 1

*#ncorrect re%erence to electrons = contraiction.

(ii) 3ean /average mass of a molecule/entity/formula 1

l/12th mass of atom of 12 1

<@ot 1/12th

mass o% molecule o%12

*mar+ inepenently.

, 3ass of 1 mole of molecules/entities (1)

l/12th

mass of 1 mole of12

(1)

, 4verage mass of a molecule/entity (1)

"elative to the mass of a12

atom ta*en as 12 / 12-%%% (1)

*Mean/a!erage = state or e-plaine.

*mass = state or e-plaine.

*Penalise :weig"t; once only.

*#gnore :a!erage : mass o% 12.

*$o not allow :mass o% a!erage molecule.

(b) (i) 2s22p

6!s

2!p

6's

1!d

1%*accept 8

:5s

2 . 1

*accept su,scripts or caps.

<Penalise missing s"ell num,ers

(ii) d / K <@?T 8/ :transition element 1

(iii) !6 <@?T 8('& 1




(c) (i) 3ore6!

u atoms than6

u atoms 1

*iea o% more a,unant6!

u isotope @?T Just re%erence to

pea+ "eig"ts.

(ii) Electron from electron gun / high speed electron / high energy electron 1

*accept electron gun %ire at.

<@?T :,om,are wit" electrons

*noc* electron off (u atom) / idea of loss of e

/ appropriate e;uation 1

*Mar+ inepenently.

(iii)6!

u2$

or e;uivalent <@?T (8'& penalise t"is error once only 1

m/z , 6!/2 (,!1-) or e;uivalent 1

3ore energy needed to remove second electron , 16!

u

2$

statistically less li*ely to remove second electron(?dea that not many

6!u

2$ ions formed , e>plains 7hy fe7 are

formed e-g- more energy needed)

#% : (8

u; not gi!en4 can only awar M2 M8

otes on I?f 6 used= lose 31 an$ 32J

(c) (iii) I?f mass number missing from identity but appears in e>planation=

penalise 3l but allo7 32 if earnedJ[12]

44. (a) (i) 1%% +l% !

+ %-%% , -%% + 1% 2

(mol) accept +1% 2

/ %-% 1

(ii) 25-! +1% !

+ %-6%% , 1-6' + 1% 2

/ 1-6!& + l% 2

(mol) only 1

(iii) 1-6' +1% 2

(mol) 1

Mar+ conseq on *ii.

(iv) -%% + 1% 2

D 1-6' + 1% 2

, !-!6 + 1% 2

(mol) 1

Mar+ conseq on *i. *iii.

(v) !-!6 + 1% 2

+ K = 1-6& + 1% 2

(mol) #% 2'67 > 1& 2

used 1-!: + 1% 2

1

Mar+ conseq on *i!.

1-6& + 1% 2

+ l!2(-l) or 1-!: + 1% 2

+ 1!2(-l) 1

Mar+ %or M r

, 2-22 g or 1-&! g 1




(b) p8 , n"9 1

15

1'!-%n= , &-'(1) + 1%

! (mol) 1

n" p89 = , !

'

1%'-&!1-&1%&6-21%%%%%−

−

××

××

(1) 1

, '%&- '1%- () 1

Mar+ conseq on moles

Note Sig' %ig' penalty apply once i% single s% gi!en4 unless calc wor+s e-actly

[11]

45. (a) (i) (atoms 7ith the) same number of protons / same atomic number /

atoms of the same element@ 1*molecules = contraiction.

But different number of neutrons / different mass number@ 1

*not i%%erent atomic mass or Ar .

(ii) detected by0 $ve ions collide 7ith / are directed or deflected to /

are collected at the detector@ 1

causing current to flo7 / detected electrically /

idea of electricity or voltage generated@ 1

*not :c"arge prouce; or :etecte electronically;.

abundance measured0 idea that current depends on

abundance/number of ions hitting detector@ 1

(b) (i) mean /average mass of an atom / all the isotopes@

l/12th

mass of atom of12

@

*mar+ inepenently.

O"

mass of 1 mole of atoms (of an element)@

l/12th

mass of l mole of12

@

O"

average mass of a molecule/entity@

relative to the mass of a12

atom ta*en as 12 / 12-%%%@ 2

*penalise :weig"t; once only.

*ignore :a!erage; mass o%12

.

*o not allow :mass o% a!erage atom .

(ii)1%%

)6-25()6-:16()&-'( ×+×+×

@ 1

, -:@ 1

(c) (i) 1s2 2s

22p

6!s

2!p

6@ 1




*accept su,scripts or capsE ignore 5sL. *penalise missing s"ell

num,ers.

(ii) highest energy level / last subDshell to be filled / is (!)d@

?R

outermost electrons in the d subDshell/orbital@ 1

*not incomplete su,s"ell.

*not !alance electron in su,s"ell.

(iii) no difference@ 1

same e

arrangement / same number of e

/ same valence e

-

?R

same chemical properties@

?R

chemical properties determined by electrons@ 1

*M2 tie to correct answer %or M1.

[13]

46. (a) moles %! , 15 R 1% !

+ 1- , (%-262 mol)@ 1

moles #b(O! )2 , + %-262 , (%-1!1 mol)@ 1

3r #b(O! )2 , !!1(-2)@ 1

mass #b(O! )2 , !!1-2 > %-1!1,'!- g@ 1

*accept 58'2 58'7.

*M1 M2 are process mar+s' #% error in M14 or in M24 o notmar+ M5

consequentially4 i'e' o not awar M5.

*i% atomic num,ers use in M84 o not awar M5.

(b) (i) p8 , n"9@ 1

%%&-!1

1%1-1%%%%%

"9

p8n

'

×

××== @ 1

, !-61 R 1% !

@ 1

*#% pressure not con!erte to Pa4 ma- 2.

*#% n = pV

RT use = CE M2 = M8 = &.




(ii) moles%2 , '/ + !-61 + 1% !

@ 1

<mar+ is %or use o% 5/)

= 2-&: + 1% !

?R 1-5&+1% !

@ 1

3r O2 , '6@ 1

massO2 , '6 +2-&:+l% !

, %-1-!!(g) ?R %-%&21 (g)@ 1

* i% atomic num,ers use4 M8 = M5 = &.

[11]

47. *penalty %or sig %ig error =1mar+ per question.

(a) neutron0 relative mass , 1 relative charge , % 1

*not :neutral;.

electron0 relative mass , 1/1&%% T %/negligible or

-6 + 1% '

T % relative charge , 1 1

(b)15

O/O15

mass number ( $o not accept 16'&) 1

o>ygen symbol HO 1

*i% :o-ygen; I :mass num,er = 16;*1..

*i% :o-ygen;I :mass num,er = 16;*&..

*i% at @ & gi!en ,ut N 74 treat as :con; %or M2.

*i% lp on 0e4 iagram = &.

*ignore ,on angles.

*not ot an cross iagrams.

(c) 2

l

l l B e l

UoL Linear (1) beat / 8Dshaped / angular (1) 2

*mar+ name an s"ape inepenently.

*accept *istorte. tetra"eral.

*i% ,alls instea o% sym,ols4 lose M1 9 can awar M2.

*penalise missing :l; once only.

*not :nonlinear;.




(d) M r (3g(O!)2 , &(-!) *i% At @L use4 lose M1 an M2. 1

moles 3g(O)2 , %-%152 (conse; on 7rong 32) (ans7er to !$ s-f-) 1

moles l , 2 + %-%152 , %-%!'' or %-%!'! (mol) *process mar+. 1

vol l ,1

1%%%%!'!-% ×, !'-! !'- (cm!) *unless wrong unit. 1

*i% caniate used &'&16 or &'&161 lose M2.

*Just answer wit" no wor+ing4 i% in range = *5.' i%4 say4 85 t"en =*2..

*i% not 2D1 ratio4 lose M8 an M5.

*i% wor+ on l4 C = &/5.[12]

48. (penalty for sig fig error ,1mar* per ;uestion)

(a) (i) moles O! , 1-%%/1%1-1 , :-&: + 1%D!

(mol) 1

(ii) p8 , n"9 or n , p8/"9 1

moles O2 , n , RT

pV , (1)

2:&!1-&

1%22-11%%%%% '

×

×× (1) 2

, '-:! + 1%D! (mol) 1

*mar+ answer %irst 9 c"ec+ ,ac+ i% wrong.

*transcription error lose M84 mar+ M5 conseq on error.

*i% :untracea,le; %igures use M8=M5=&.

*i% wrong temp con!ersion 9 lose M8 9 conseq M5.

*i% n = RT/pV C4 lose M8 an M5.

(b) (i) simplest/lo7est ratio of atoms of each / element/s in a compound /

substance / species / entity / molecule 1

(ii) O @ ?

1-!:

:-'

1'

-16

16

6-!5(1)

1-15 1-1& 2-!

1 1 2 O

2

(1) !*M8 tie to M2.4 *M8 can ,e trans%erre %rom equation i% ratio correct

,ut CF not gi!en. *i% calc in!erte4 lose M2 an M8.4 *i% use At @ 1 /

wrong @o %or Ar t"en C4 lose M2 an M8. *i% B o% ? missing4

awar M2 only.




(c) 2O! T 2O

2 $ O

2 or fractions/multiples 1

*accept 2 O@?! O

2 @

2?

' I ?

2 .

*o @?T accept :Q; in equation.[10]

49. (a) 3ean (average) mass of an atom / all the isotopes or 1

1/12th

mass of atom of12

1

3ass of 1mole of atoms of an element or

1/12th

mass of 1mole of12

average mass of an atom / all the isotopes

"elative to the mass of a12

atom ta*en as e>actly 12 / 12-%%%

(penalise H7eight once only) (ignore Haverage mass of 12)(not Hmass of average atom)

(b) 42 , (6' + %-!&:) $ (66 + %-25&) $ (65 + %--1'5) $ (6& + %-1&6) 1

, 6-5

*mar+ M2 conseq on transcription error or incorrect aition o% B. 1

identity0 Ainc / n 1

*onseq on A2 ,ut only i% t"eir A2 is wit"in range o% Perioic Ta,le.

(c) electron gun (fires) electrons or high speed/energy electrons 1

*not Just :,om,are ,y electrons; or :,om,are ,y electron gun;.

*noc*s off e

from - 1

*may ,e earne %rom a real or generic equation.

"easons0 to allo7 ions to be0 1

accelerated (by an electric field)

deflected (by a magnet/magnetic field) 1

detected / description of current formed at the detector/sensor 1

*accept in any orer.*allow clear escriptions o% :accelerate;4 :e%lecte;4 :etecte;.

[10]




50. (a) 4toms/isotopes/particles/species 7ith the same (number of) protons and 1

different (number of) neutrons

<@ot atomic num,er/mass num,er/molecules/same element/i%%

electrons

(b) Al !515 15 < l 1

3ass number 1

<@ot 86'& <Mar+ inepenently <ignore c"arges

(c) (i) 2s22p

6!s

2!p

6!d

1%'s

2'p

21

<allow re!erse 5s2

8 1&

<allow capitals/su,scripts

(ii) 4r ,1%%

'!-2)(5' !2-')(52 2'-')(5% ×+×+×1

<rong approac" or not i!iing ,y 1&& = C = &

, 52-' 1

<Answer to 1 'p' <Mar+ conseq on transcription error

(iii) 3agnet/electromagnet/magnetic field / electric field/charge on

negative/accelerator plate 1

orrect lin* bet7een deflection and m/z 1

orrect lin* bet7een deflection and field 1

<Penalise :re%lecte;/;i%%racte; once only

<#gnore re%erences to molecules/atoms/particles

<onsolation mar+D allow correct lin+ ,etween mass an

e%lection %or 1 mar+ out o% t"e 2

(iv) 52 e +2 only 1

Same m/z as8(

S I

1

<Mar+ inepenently

[11]

51. (a) (i) 4vogadros number/constant of molecules/particles/species / 6 × 1%2!

1

<@ot :atoms;

r same number of particles as (there are atoms)

<@ot molecules

in 12-(%%)g of12

1




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Atomic Structure and Amount of Substance A