2001 - JAMB Chemistry Past Questions and Answers - page 3
21
What current in amperes will deposit 2.7g of aluminium in 2 hours?
[Al = 27, F = 96 500 C mol-1]
[Al = 27, F = 96 500 C mol-1]
A
32
B
8
C
4
D
16
correct option: c
Al3+ + 3e → Al
3 * 96500 → 27
I = 3600 * 2 → 27
I = (2.7/27) * ((3 * 96500)/(3600 * 2))
= 4.025 ≈ 4
Users' Answers & Comments3 * 96500 → 27
I = 3600 * 2 → 27
I = (2.7/27) * ((3 * 96500)/(3600 * 2))
= 4.025 ≈ 4
22
Ethanoic acid is
A
tribasic
B
unionizeable
C
monobasic
D
dibasic
correct option: c
Users' Answers & Comments23
C(s) + 2S(g) → CS2(g)
ΔH = +89 kJ mol-1
The chemical equation above implies that
ΔH = +89 kJ mol-1
The chemical equation above implies that
A
each of carbon and sulphur has 89 kJ of energy
B
both carbon and sulphur contribute 89 kJ of energy
C
89 kJ of energy is released
D
89 kJ of energy is absorbed
correct option: d
Users' Answers & Comments24
2SO2(g) + O2(g) ↔ 2SO3(g)
ΔH = -189 kJ mol-1
The equilibrium constant for the reaction above is increased by
ΔH = -189 kJ mol-1
The equilibrium constant for the reaction above is increased by
A
Increasing the temperature of the system
B
Increase the pressure of the system
C
The addition of a catalyst to the system
D
Increasing the surface area of the vessel
correct option: b
Users' Answers & Comments25
3Cu(s) + 8HNO3(aq) 3Cu(NO3)2(aq) + 4H2O(l) + 2NO(g)
In the equation above, copper is
In the equation above, copper is
A
an electron acceptor
B
a base
C
an oxidizing agent
D
a reducing agent
correct option: d
Users' Answers & Comments26
When ΔH is negative, a reaction is said to be
A
ionic
B
reversible
C
exothermic
D
endothermic
correct option: c
Users' Answers & Comments27
As the concentration of an electrolyte reduces, the conductivity
A
reduces to zero
B
decreases
C
increase
D
is unaffected
correct option: c
Users' Answers & Comments28
In which of the following reactions has the oxidation number of nitrogen increased?
A
2NO(g) + Br2(l) → 2NOBr(l)
B
2NO(g) + O2(g) → 2NO2(g)
C
FeSO4(aq) + NO(g) → Fe(NO)SO4(s)
D
2NO(g) + Cl2(g) → 2NOCl(l)
correct option: b
Users' Answers & Comments29
NH3(g) + HCl(g) → NH4Cl(s)
The entropy change in the system above is
The entropy change in the system above is
A
negative
B
indeterminate
C
positive
D
zero
correct option: a
Users' Answers & Comments30
Fermentation is the
A
breaking down of carbohydrate to glucose
B
conversion of sugar to alcohol in the presence of yeast
C
breaking down of sugar to carbohydrate
D
conversion of alcohol to sugar in the presence of yeast
correct option: b
Users' Answers & Comments