2004 - JAMB Chemistry Past Questions and Answers - page 3
22
ZnO(s) + CO(g) → Zn(s) + CO2(g)
In the reaction above, Zinc has been
In the reaction above, Zinc has been
A
decomposed
B
displaced
C
oxidized
D
reduced
correct option: d
Users' Answers & Comments23
Which of the following acts as both reducing and oxidized agent?
A
H2
B
SO2
C
H2S
D
CO2
correct option: b
Users' Answers & Comments24
In the electrolysis of brine, the anode is
A
platinum
B
copper
C
zinc
D
carbon
correct option: d
Users' Answers & Comments25
The mass of silver deposited when a current of 10a is passed through a solution of silver salt for 4830s is
[Ag = 108, F = 96500 c mol-1]
[Ag = 108, F = 96500 c mol-1]
A
108.0g
B
54.0g
C
27.0g
D
13.5gq
correct option: b
Ag + ie → Ag+
If w 96500 C deposit 108g of silver
∴ 10 * 4830 will deposit (10 * 4830 * 108)/96500
= 5216400/96500 = 54.06g
Users' Answers & CommentsIf w 96500 C deposit 108g of silver
∴ 10 * 4830 will deposit (10 * 4830 * 108)/96500
= 5216400/96500 = 54.06g
26
2CO(g) + O2(g) → 2CO2(g)
Given that ΔH[CO]is -110.4 kJmol-1 and ΔH[CO2] is -393.0 kJmol-1, the energy change for the reaction above is
Given that ΔH[CO]is -110.4 kJmol-1 and ΔH[CO2] is -393.0 kJmol-1, the energy change for the reaction above is
A
-503.7 kJ
B
-282.6 kJ
C
+282.6 kJ
D
+503.7 kJ
correct option: b
Energy change (ΔH) = 2ΔHCO2 - (2ΔHCO + ΔHO)
= 7x - 393 - (7 * 110.4 + 0)
= -393 + 110.4 = -282.6 kJ
Users' Answers & Comments= 7x - 393 - (7 * 110.4 + 0)
= -393 + 110.4 = -282.6 kJ
27
Which of the following hydrogen halides the highest entropy value?
A
HF
B
HCl
C
HBr
D
HI
correct option: a
Users' Answers & Comments28
N2O4(g) ↔ 2NO2(g)
In the endothermic reaction above, more product formation will be favoured by
In the endothermic reaction above, more product formation will be favoured by
A
a constant volume
B
an increase in pressure
C
a decrease in pressure
D
a decrease in volume
correct option: c
Users' Answers & Comments29
Which of the following shows little or no net reaction when the volume of the system is decreased?
A
H2(g) + I2(g) ↔ 2HI(g)
B
2NO2(g) ↔ N2O4(g)
C
PCl5(g) ↔ PCl3(g) + Cl2(g)
D
2O3(g) ↔ 3O2(g)
correct option: a
Users' Answers & Comments30
The allotropy of carbon used in the decolourization of sugar is
A
Graphite
B
Soot
C
Charcoal
D
Lampblack
correct option: c
Users' Answers & Comments