2006 - JAMB Chemistry Past Questions and Answers - page 3
21
When 50cm2 of a saturated solution of sugar of molar mass 342 g at 40oC was evaporated to dryness, 34.2g of dry solid was obtained. The solubility of sugar at 40oC is
A
2.0 mol dm-3
B
3.5 mol dm-3
C
7.0 mol dm-3
D
10.0 mol dm-3
correct option: a
solubility = mole * 1000cm3/volume
mass/molar mass * 1000cm3/volume
= 34.2/342 * 1000cm3/50cm3-3
Users' Answers & Commentsmass/molar mass * 1000cm3/volume
= 34.2/342 * 1000cm3/50cm3-3
22
Which of the following results in the fall of acid rain?
A
Oxides of lead
B
Particulate matter
C
Oxides of sulphur
D
Gaseous hydrocarbon
correct option: c
Users' Answers & Comments23
Water has the ability to dissolve almost all substance because its molecules has a structure with
A
one positive end and one neutral end
B
one positive end and one negative end
C
two negative ends
D
two positive ends
24
When a crystal was added to the clear solution of its salt, the crystal did not dissolve and the solution remained unchange. This showed that the solution was
A
supersaturated
B
concentrated
C
unsaturated
D
saturated
correct option: d
Users' Answers & Comments25
A particle that contains 11 protons, 12 neutrons and 10 electrons is probably a
A
neutral non-metal
B
metallic ion
C
non-metallic ion
D
neutral metal
correct option: b
Users' Answers & Comments26
A difference between chemical and physical change is that in a chemical change
A
oxygen is consumed
B
heat is supplied
C
a reversible process oocurs
D
a new substance is formed
correct option: d
Users' Answers & Comments27
The volume of 2.5 moles of oxygen at s.t.p is
[Molar volume of a gas at s.t.p = 22.4 dm3]
[Molar volume of a gas at s.t.p = 22.4 dm3]
A
50.0 dm3
B
84.0 dm3
C
28.0 dm3
D
56.0 dm3
correct option: d
1 mole of gas at s.t.p = 22.4
2.5 moles → 2.5 * 22.4 = 56.00 dm3
Users' Answers & Comments2.5 moles → 2.5 * 22.4 = 56.00 dm3
28
Nuclear fission involves the splitting of a heavy element into two nuclei of
A
nearly equal masses with a relaese of energy and radiaton
B
equal masses with a relaese of energy
C
equal masses with a release of energy and radiation
D
unequal masses without any relaese of energy
correct option: a
Users' Answers & Comments29
What is the molar mass of a substance, if 0.4 mole of the substance has a mass of 25.0g?
A
62.5 g
B
40.0 g
C
6.3 g
D
2.5 g
30
The element with the electron configuration 1s22s22p3 is
A
calcium
B
chlorine
C
oxygen
D
nitrogen
correct option: d
Users' Answers & Comments