Year : 
2001
Title : 
Chemistry
Exam : 
JAMB Exam

Paper 1 | Objectives

21 - 30 of 50 Questions

# Question Ans
21.

What current in amperes will deposit 2.7g of aluminium in 2 hours?
[Al = 27, F = 96 500 C mol-1]

A. 32

B. 8

C. 4

D. 16

Detailed Solution

Al3+ + 3e → Al
3 * 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

C
23.

C(s) + 2S(g) → CS2(g)
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

D
24.

2SO2(g) + O2(g) ↔ 2SO3(g)
ΔH = -189 kJ mol-1
The equilibrium constant for the reaction above is increased by?

A. decreasing 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

Detailed Solution

Decrease in temperature favors in Equilibrium Constant[k]
25.

3Cu(s) + 8HNO3(aq) 3Cu(NO3)2(aq) + 4H2O(l) + 2NO(g)
In the equation above, copper is

A. an electron acceptor

B. a base

C. an oxidizing agent

D. a reducing agent

D
26.

When ΔH is negative, a reaction is said to be

A. ionic

B. reversible

C. exothermic

D. endothermic

C
27.

As the concentration of an electrolyte reduces, the conductivity

A. reduces to zero

B. decreases

C. increase

D. is unaffected

C
28.

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)

B
29.

NH3(g) + HCl(g) → NH4Cl(s)
The entropy change in the system above is

A. negative

B. indeterminate

C. positive

D. zero

A
30.

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

B
21.

What current in amperes will deposit 2.7g of aluminium in 2 hours?
[Al = 27, F = 96 500 C mol-1]

A. 32

B. 8

C. 4

D. 16

Detailed Solution

Al3+ + 3e → Al
3 * 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

C
23.

C(s) + 2S(g) → CS2(g)
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

D
24.

2SO2(g) + O2(g) ↔ 2SO3(g)
ΔH = -189 kJ mol-1
The equilibrium constant for the reaction above is increased by?

A. decreasing 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

Detailed Solution

Decrease in temperature favors in Equilibrium Constant[k]
25.

3Cu(s) + 8HNO3(aq) 3Cu(NO3)2(aq) + 4H2O(l) + 2NO(g)
In the equation above, copper is

A. an electron acceptor

B. a base

C. an oxidizing agent

D. a reducing agent

D
26.

When ΔH is negative, a reaction is said to be

A. ionic

B. reversible

C. exothermic

D. endothermic

C
27.

As the concentration of an electrolyte reduces, the conductivity

A. reduces to zero

B. decreases

C. increase

D. is unaffected

C
28.

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)

B
29.

NH3(g) + HCl(g) → NH4Cl(s)
The entropy change in the system above is

A. negative

B. indeterminate

C. positive

D. zero

A
30.

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

B