2015 - JAMB Chemistry Past Questions and Answers - page 1
1
The filter in the cigarette reduce the nicotine construct by
A
burning
B
absorption
C
evaporation
D
absorption
correct option: a
Nicotine is a substance in cigarette which makes difficult to make one stop smoking. This can be derived by burning. Options B,C,D will not reduce this nicotine
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Which of these require crystallization most?
A
Drug making
B
Cement making
C
Paint making
D
Perfume making
correct option: a
Crystallization is required the most in industries where the purity of their products is important e.g in the manufacture of drugs and in sugar production. Options B,C and D do not undergo crystallization
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Iron is often galvanized in order to
A
Make it more malleable
B
Remove the impurities unit
C
Protect it against corrosion
D
Render it passive
correct option: c
Iron is galvanized with zinc covering to protect it against corrosion. Option A, B, D are the main reasons iron is galvanized
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In the industrial production of H2 is removed by (solution)
A
washing under pressure
B
drying over phosphorus (V) oxide
C
passing the mixture to the limewater
D
using ammonical copper (I) chlorine
correct option: a
Washing under pressure is an action in the industrial production of H. Options B,C,D will not yield Co and H
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The gas that is most useful in protecting humans against solar marathon is
A
chlorine
B
ozone
C
carbon IV oxide
D
hydrogen sulphur
correct option: b
The ozone layer or ozone shield refers to a region of Earth's stratosphere that absorbs most of the Sun's ultraviolet (UV) radiation. It contains high concentrations of ozone (O3) relative to other parts of the atmosphere, although still very small relative to other gases in the stratosphere
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Vulcanization involve the removal of
A
monometer
B
the single bond
C
the double bond
D
a polymer
correct option: c
Vulcanizer is the removal of double bend in a chemical reaction. Option A,B,D can not be removed by vulcanizer
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The acid in electrolysis of water is dilute
A
HNO3
B
CH3COOH
C
H2SO
D
HCl
correct option: c
HeSO4 is the acid used in the electrolysis of water. Option A,B,D are concentrated acid and they will react with the water
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A small quantity of solid ammonium chloride (NH4Cl) texted gently in a test tube, the solid gradually disappear produce two gases. Later, a white cloudy deposit was absence on the cooler part of the test tube. The ammonium chloride is to have undergo
A
distillation
B
sublimation
C
precipitation
D
evaporation
correct option: b
Sublimation is the transformation of solid gaseous state without passing through the liquid state. Options A,C,D do not show case these character of sublimation as they do not bye pass states. They are in a particular order
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When salt loses its water of crystallization to the atmosphere on exposure, the process is said to be
A
efflorescence
B
déliquescence
C
effervescence
D
fluorescence
correct option: a
Efflorescence is a process of long exposure to the atmosphere which favors salt loss of water. Options B, C, D are not related to loss of water
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Atomicity of ozone is
A
1
B
2
C
3
D
4
correct option: c
Ozone means Oz as the atomicity is 3. Option A,B,D cannot give ozone because their atomicity is not 3
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