BISHOPS
Grade 12 June Exam Paper II
MEMO
SECTION A
AMMENDMENTS
TOTAL 147
Question 1
1.1
SATURATED or ALKANES 
1.2
REVERSE (REACTION) (accept reversible or equilibrium rxn.)
1.3
BOND/DISSOCIATION ENERGY
1.4
CATHODE 
1.5
OSTWALD PROCESS
[5]
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Question 2
2.1 B 2.2 B 2.3 C 2.4 C 2.5 A 2.6 C 2.7 C 2.8 B 2.9 D (no answer) 2.10 C
9 x (2) = [18]
___________________________________________________________________________________
Question 3
3.1
H2 /time 
(1)
3.2
concentration (of HCl)
(1)
3.3
volume of (H2)
(1)
3.4
temperature pressure /using same person to take readings
(2)
3.5
X
(1)
3.6
rate  (of reaction / evolution of H2(g))
(1)
3.7
Concentration of reactants decreases
(2)
3.8
reached completion / stopped / reactants used up (any)
(1)
3.9
Rate increases with concentration or dir. proportional .
(Rate decreases with time only)
(2)
3.10
Higher concentration gives higher rate of collisions leads to increased rate/more gas (2)
3.11
Any question that links rate to concentration / time / amount.
(2)
[16]
Question 4
4.1
Reversible reaction with fwd & reverse rates equal / no macroscopic changes / continual
microscopic changes / concentrations constant (any 2 (1) mark each) 
(2)
4.2
4.2.1
Kc =
4.2.2
Equilibrium lies to the RIGHT/high yield
(1)
4.2.3
NO CHANGE
(1)
4.2.4
INCREASED
(1)
4.2.5
When the pressure is increased, the equilibrium will shift according to Le Chateliers
principle to reduce the pressure by favoring the side with the least number of moles of
gas forward reaction favored/eqm. shifts to RHS and amount of SO3(g) INCREASES
[ SO3 ]2

[ SO2 ]2 .[O2 ]
(1)
4.3
(3)
2SO2(g)
+
O2(g)
⇌
2SO3(g)
Awarded for
Initially:(mol)
6
x
0
(5 marks)
React/Form:
(mol)
4.5 
4.5/2 
4.5
( CORRECT USE
of RATIO)
6 - 1.5 =
Eqm: (mol)
X - (4.5/2)

[ ]: (mol/dm3)
Kc =



((X-(4.5/2))/3)
0,5
[ SO3 ]2
[ SO2 ]2 .[O2 ]

.: 6.5 =
=
( SUBTRACTING)
4.5/3
(/ v = 3 dm3)
(4.5 / 3) 2

(0.5)2 *(( X  (4.5 / 2)) / 3)
2.25

6.5
4.5
0.25
.
X-
2.25
3.00
X- 2.25
3
.
2.25
=
0.25
.
6.50
X =
6.4
mol

(8)
4.4
4.4.1
5 min
(1)
4.4.2
reaction is not in equilibrium / concentrations changing
(1)
4.4.3
Temperature decreased – forward reaction favored by lower T since fwd. exothermic and
Eqm. will shift to increase Temp according to Le CHat
or pressure increased so shifts in direction of least number of moles – fwd
(3)
[22]
Question 5
5.1
5.1.1
ETHENE 
5.1.2
(2,2)-dimethylpropane  (award separately must be one word for 2 marks)
(2)
(2,2 not necessary but if numbers given MUST be 2,2)
(2)
5.2
B & C 
5.3
5.3.1
CnH2n 
(2)
5.3.2
CnH2n+2 
(2)
5.4.1
C4H10 + 6.5O2  4CO2 + 5H2O
5.4.2
use up available oxygen produce carbon dioxide / CO can cause suffocation (2)
5.4.3
A
(1)
5.4.4
van der waals forces weakest intermolecular forces
(2)
5.4.5
alkanes flameable / pressurized cans danger of explosion / fire / injury
(2)
5.4
H
5.5
C
(2)
H
H
C
C
H
+ H
reactants prod  bal (accept multiples) (3)
Br

H
H
H
H
C
C

C
Br
H

H
5.6
5.7

H
H
H
(3)
5.6.1
i) ADDITION / HYDROGENATION ii) SUBSTITUTION / HALOGENATION  (2)
5.6.2
I) X 
(1)
5.7.1
FRACTIONAL DISTILLATION 
(1)
5.7.2
energy crisis 
global warming /drought, rising sea levels, pollution, depletion of
resources/ fossil fuels etc.
(2)
[29]
Question 6
6.1
E (breaking) = 2E(H-H) + E(O=O) = 2*436+499 = 1371 kJ
6.2
E (forming) = 4E(H-O) = 4*460 = 1840 kJ
6.3
Exothermic Hr = E(breaking) – E(forming) = 131-1840 = -469 kJ
6.4
accept Ea

SHAPE
(3)
-1
(3)
-1 only)
(3)
(If kJ.mol
(5)



6.5
No harmful compounds produced – only water
6.6
Difficult / expensive to produce H2  Hazadous / explosive  or other... lack of infra structure
for gas fuels / difficult to store / high pressures dangerous etc...
(2)
(2)
[18]
Question 7
7.1
7.1.1
copper
(2)
7.1.2
cations move -
into salt bridge from copper electrode 
-
from salt bridge into Ag electrode
(2)
7.1.3
electrons
(2)
7.1.4
Eocell = Eocathode – Eoanode = 0.80 – 0.34 = 0.46 V
(3)
7.1.5
2Ag+ + Cu  2Ag + Cu2+ React Prod Bal (-1 if eqm arrows)
7.1.6
(Also mark Cu  Cu+ correct but max 2 marks)
(3)
DECREASED 
(2)
7.2
SECONDARY
(1)
7.3
Zn + HgO   ZnO + Hg
(accept if H2O & OH- ions included as long as still balanced)
(2)
7.4
1A x 60 x 60 = 3600 C
(2)
7.5
q = I x t  = 1.65 x 6  = 9.9 Ah
(3)
7.6
7.6.1
2Cl-  Cl2 + 2e-
7.6.2
sodium hydroxide
(1)
7.6.3
cleaning agent / soap making / etc. 
(1)
7.6.4
allows the passage of sodium, and water

(2)
(1)
[27]
Question 8
→ 2 NO2 (g)
 (-1 per error)
8.1
2 NO (g) + O2
8.2
oxidation of ammonia
(1)
8.3
H2O 
(1)
8.4
C: sulphuric acid
8.5
problem eutrophication remedy (soil testing, buffer zones etc) 
(g)
D: ammonium nitrate
(2)
(2)
change pH in soil / burning crops any problem (1) + remedy (1)
or other ENVIRONMENTAL (NOT effect on humans e.g. blue baby etc.)
(2)
8.6
manure or compost or other
(2)
8.7
create jobs / reduce the cost of imported fertilizers / revenue from exporting --- other (2)
[12]
TOTAL 147