1990 - JAMB Chemistry Past Questions and Answers - page 5
41
If 10.8 g of silver is deposited in a silver coulometer volume of oxygen liberated is?
A
0.56 dm3
B
5.60 dm3
C
11.20 dm3
D
22.40 dm3
correct option: a
Ag+ + e-
H = 108 g Ag
= 0.11 10.8 Ag
4OH → O2 + 2H2O + 4e
4F ↔ 1mole O2
4F = 22.4 dm3 χ 0.1 = 0.56 dm3
Users' Answers & CommentsH = 108 g Ag
= 0.11 10.8 Ag
4OH → O2 + 2H2O + 4e
4F ↔ 1mole O2
4F = 22.4 dm3 χ 0.1 = 0.56 dm3
42
0.1 faraday of electricity deposited 2.95 g of nickel during electrolysis of an aqueous solution.
Calculate the number of moles of nickel that will be deposited by 0.4 faraday?
(Ni = 58.7)
Calculate the number of moles of nickel that will be deposited by 0.4 faraday?
(Ni = 58.7)
A
0.20
B
0.30
C
0.04
D
5.87
correct option: a
0.1F ↔ 2.95 g Ni = 0.4F ↔ 11.8 g Ni
No of moles = (11.8)/(58.2) = 0.20 moles
Users' Answers & CommentsNo of moles = (11.8)/(58.2) = 0.20 moles
43
A
sublimation, condensation and freezing
B
sublimation, vapourization and solidification
C
freezing, condensation and sublimation
D
evaporation, liquefaction and solidification
correct option: a
Users' Answers & Comments44
A
A
B
B
C
C
D
D
correct option: b
Users' Answers & Comments45
A
2-ethyl-4-methylpent-2-ene
B
3,5-dimethylhex-3-ene
C
2,4-dimethylhex 3-ene
D
2-methyl-4-ethylpent-3-ene
correct option: a
Users' Answers & Comments46
A
A
B
B
C
C
D
D
correct option: b
Users' Answers & Comments47
A
a displacement reaction
B
a neutralization reaction
C
an elimination reaction
D
saponification
correct option: b
Users' Answers & Comments48
A
A
B
B
C
C
D
D
correct option: a
Users' Answers & Comments49
The Avogadro number of 24g of magnesium is the same as that of
A
1g of hydrogen molecules
B
16g of oxygen molecules
C
32g of oxygen molecules
D
35.5g of chlorine molecules