2019 - JAMB Chemistry Past Questions and Answers - page 2

11

Which of the following metals is the most essential in the regulation of blood volume, blood pressure and osmotic equilibrium?

A
Zinc
B
Manganese
C
Sodium
D
Iron
correct option: c
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12

Which of the following alkaline metals react more quickly spontaneously with water?

A
Calcium
B
Beryllium
C
Magnesium
D
Strontium
correct option: a
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13

When chlorine water is exposed to bright sunlight, the following products are formed

A

HCl\(_{(aq)}\) and Cl\(_2\)

B

HOCl\(_{(aq)}\) and Cl\(_2\)

C

HCl\(_{(aq)}\) and O\(_2\)

D

HOCl\(_{(aq)}\) and O\(_2\)

correct option: c

By exposing chlorine water to sunlight, it decomposes into HCl gas and oxygen. When chlorine water is exposed to strong sunlight it produces an odourless and colourless gas called oxygen.

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14

Which process(es) is/are involved in the turning of starch iodide paper blue-black by chlorine gas?

A

chlorine attacks the starch to give the blue-black color

B

chlorine attacks the iodide ion to give the blue-black color

C

chlorine oxidizes the iodide ion to produce iodine which attacks the starch to give the blue-black color

D

iodine attacks the starch to give the blue-black color

correct option: c

The oxidization of iodide (by chlorine) ion produces the iodine which attacks the starch to give the blue-black colour

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15

Which of the following is a set of neutral oxides?

A

N\(_2\)O, H\(_2\)O, CO

B

N\(_2\)O, SO\(_2\), CO

C

N\(_2\)O, Na\(_2\)O, ZnO

D

N\(_2\)O, SO\(_3\), NO

correct option: a

Neutral oxides show neither basic nor acidic properties. As a result of this behaviour neutral oxides do not form salts when reacted with acids or bases, e.g., carbon monoxide (CO); nitrous oxide (N2O); nitric oxide (NO), etc., are neutral oxides

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16

SO\(_3\) is not directly dissolved in water in the industrial preparation of H\(_2\)SO\(_4\) by the contact process because

A
SO\(_3\) is an acidic gas
B
Acid is usually added to water and not water to acid
C
The reaction between SO\(_3\) and water is violently exothermic
D
SO\(_3\) does not dissolve readily in water
correct option: c
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17

Which of the following statements does not show Rutherford's account of Nuclear Theory? An atom contains a region

A

which contains protons and neutrons

B

which is positively charged

C

which is massive and can cause deflection of a few projectiles

D

which is very large and in which close to 98% of projectiles pass undeflected

correct option: c

Rutherford's account of Nuclear theory does not take into account the fact that atoms contain a massive region and cause deflection of from projectiles. He concluded that all of the positive charge and the majority of the mass of the atom must be concentrated in a very small space in the atom's interior, which he called the nucleus. The nucleus is the tiny, dense, central core of the atom and is composed of protons and neutrons

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18

Elements X and Y have electronic configurations 1s\(^2\)2s\(^2\)2p\(^4\) and 1s\(^2\)2s\(^2\)2p\(^6\)3s\(^2\)3p\(^1\) respectively. When they combine, the formula of the compound formed is

A
XY
B
X\(_2\)Y
C
Y\(_2\)X\(_3\)
D
X\(_2\)Y\(_3\)
correct option: c
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19

By what amount must the temperature of 200cm\(^3\) of Nitrogen at 27°C be increased to double the pressure if the final volume is 150cm\(^3\) (Assume ideality)

A
150°C
B
177°C
C
75°C
D
120°C
correct option: b
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20

The combustion of carbon(ii)oxide in oxygen can be represented by equation.
2CO + O\(_2\) → 2CO\(_2\)
Calculate the volume of the resulting mixture at the end of the reaction if 50cm\(_3\) of carbon(ii)oxide was exploded in 100cm\(_3\) of oxygen

A
75cm\(^3\)
B
125cm\(^3\)
C
100cm\(^3\)
D
50cm\(^3\)
correct option: b
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