2000 - JAMB Chemistry Past Questions and Answers - page 2
11
A
0.750 mole
B
0.950 mole
C
2.375 moles
D
4.750 moles
correct option: a
Users' Answers & Comments12
A
A
B
B
C
C
D
D
correct option: b
Users' Answers & Comments
14
A mixture of iodine and sulphur crystals can be separated by treatment with
A
Water to filter off sulphur
B
carbon (IV) sulphide to filter off iodine
C
ethanoic acid to filter off sulphur
D
methanol to filter off iodine
correct option: b
Users' Answers & Comments15
Sieving is a technique used to separate mixture containing solid particles of
A
small sizes
B
large sizes
C
differents sizes
D
the same sizes
correct option: c
Users' Answers & Comments16
Which of the following compounds is composed of Al, Si, O and H?
A
Epsom salt
B
Limestone
C
Clay
D
Urea
correct option: c
Users' Answers & Comments17
50 cm3 of carbon (II) oxide was exploded with 150 cm3 of air containing 20% oxygen by volume. Which of the reactants was in excess?
A
Carbon (II) oxide
B
Carbon (IV) oxide
C
Oxygen
D
Nitrogen
correct option: c
2CO + O2 → 2CO2
50cm3 → 25cm3
20% * 150 = 30cm3
30 cm3 is the volume of oxygen available for the reactions. But only 25 cm3 is required; therefore O2 is in excess
Users' Answers & Comments50cm3 → 25cm3
20% * 150 = 30cm3
30 cm3 is the volume of oxygen available for the reactions. But only 25 cm3 is required; therefore O2 is in excess
18
How many moles HCL will be required to react with potassium heptaoxodichromate (VI) to produce 3 moles of chlorine?
A
14
B
12
C
11
D
10
correct option: a
Users' Answers & Comments19
The ratio of the initial to final pressure of a given mass of gas is 1:1.5. Calculate the final volume of the gas if the initial volume was 300 cm3 at the same temperature
A
120 cm3
B
200 cm3
C
450 cm3
D
750 cm3
correct option: b
From P1V1 = P2V2
1 * V1 = 1.5 * V2
((1 * 300)/1.5) = V2
∴ V2 = 200 cm3
Users' Answers & Comments1 * V1 = 1.5 * V2
((1 * 300)/1.5) = V2
∴ V2 = 200 cm3
20
The partial pressure of oxygen in a sample of air is 452 mm Hg and the total pressure is 780 mm Hg. What is the mole fraction of oxygen?
A
0.203
B
0.579
C
2.030
D
5.790
correct option: b
Users' Answers & Comments