Year : 
2004
Title : 
Chemistry
Exam : 
JAMB Exam

Paper 1 | Objectives

1 - 10 of 50 Questions

# Question Ans
1.

When a solid substance disappears completely as a gas on heating, the substance is said to have undergone

A. evaporation

B. distillation

C. crystallization

D. sublimation

D

2.

A chemical reaction is always associated with

A. an increase in the composition of one of the substance

B. a change in the volume of the reactants

C. a change in the nature of the reactants

D. the formation of new substance

D

3.

If a solution contains 4.9g of tetraoxosulphate (VI) acid, calculate the amount of copper (II) oxide that will react with it
[Cu = 64, O = 16, S = 32, H = 1]

A. 0.8g

B. 4.0g

C. 40.0g

D. 80.0g

Detailed Solution

Equation of the reaction
H2SO4(g) + CuO(s) → Cu4(aq) + H2O
Relative molecular mass of H2SO4 = 1 + 2 + 32 + 16 + 4 = 98
Relative molecular mass of CuO = 64 + 16 =80
From the above equation, 98s of H2SO4 reacts with 80s of CuO.
∴ 4.9g of H2SO4 will react with
= (4.9 * 80)/98 of CuO = 392/98 = 4.0g
4.

What volume of gas is evolved at S.t.p if 2g of calcium trioxocarbonate (IV) is added to a solution of hydrochloric acid?
[Ca = 40, C = 12, O = 16, Cl = 35.5, H = 1 Molar volume of agas at s.t.p = 22.4 dm3

A. 112 cm2

B. 224 cm2

C. 448 cm2

D. 2240 cm2

Detailed Solution

CaCO3(s) + 2HCl(aq) → CaCl2 + H2O(l) + CO2
The relative molecular mass of CaCO3 = 40 + 12 + 16 * 3 = 52 +48 = 100 ; Relative molecular mass of CO2 = 12 + 10 * 2 = 44
From the above equation, 100g of CaCO3reacts with 44g of CO2 at s.t.p. i.e 22.4 dm3
2g of CaCO3 will react with (2*22.4)/100 of CO2 = 0.448 dm3
0.448 dm3 = 0.448 * 1000 = 448cm3
5.

According to charles' law, the volume of a gas becomes zero at

A. 0 oC

B. -100 oC

C. -273 oC

D. -373 oC

C

6.

It is difficult to achieve an orderly arrangement of the molecules of a gas because they

A. have no definite shape

B. have little force of attraction between them

C. can collide with one another in the container

D. are too small in size

C

7.

A given volume of methane diffuses in 20s. How long will it take the same volume of sulphur (IV) oxide to diffuse under the same conditions?
[C = 12, H = 1, S = 32, O = 16

A. 5s

B. 20s

C. 40s

D. 60s

Detailed Solution

Relative molecular mass of CH4 = 12 * 1 + 4 = 16
Relative molecular mass of SO2 = 32 + 10 *2 = 64
tSO2/tCH4 = √MSO2/MCH4
t/20 = √64/16 = √4
t/20 = 2
∴ t = 20 * 2 = 40sec
8.

An electron can be added to a halogen atom to form a halide ion with

A. 2 valence electrons

B. 3 valence electrons

C. 7 valence electrons

D. 8 valence electrons

D

9.

The shape of s-orbitals is

A. spherical

B. elliptical

C. spiral

D. circular

A

10.

22688Ra → x86Rn + α - particle
What is the value of x in the nuclear reaction above?

A. 220

B. 222

C. 226

D. 227

Detailed Solution

22688Ra → 22286Rn + α - particle
1.

When a solid substance disappears completely as a gas on heating, the substance is said to have undergone

A. evaporation

B. distillation

C. crystallization

D. sublimation

D

2.

A chemical reaction is always associated with

A. an increase in the composition of one of the substance

B. a change in the volume of the reactants

C. a change in the nature of the reactants

D. the formation of new substance

D

3.

If a solution contains 4.9g of tetraoxosulphate (VI) acid, calculate the amount of copper (II) oxide that will react with it
[Cu = 64, O = 16, S = 32, H = 1]

A. 0.8g

B. 4.0g

C. 40.0g

D. 80.0g

Detailed Solution

Equation of the reaction
H2SO4(g) + CuO(s) → Cu4(aq) + H2O
Relative molecular mass of H2SO4 = 1 + 2 + 32 + 16 + 4 = 98
Relative molecular mass of CuO = 64 + 16 =80
From the above equation, 98s of H2SO4 reacts with 80s of CuO.
∴ 4.9g of H2SO4 will react with
= (4.9 * 80)/98 of CuO = 392/98 = 4.0g
4.

What volume of gas is evolved at S.t.p if 2g of calcium trioxocarbonate (IV) is added to a solution of hydrochloric acid?
[Ca = 40, C = 12, O = 16, Cl = 35.5, H = 1 Molar volume of agas at s.t.p = 22.4 dm3

A. 112 cm2

B. 224 cm2

C. 448 cm2

D. 2240 cm2

Detailed Solution

CaCO3(s) + 2HCl(aq) → CaCl2 + H2O(l) + CO2
The relative molecular mass of CaCO3 = 40 + 12 + 16 * 3 = 52 +48 = 100 ; Relative molecular mass of CO2 = 12 + 10 * 2 = 44
From the above equation, 100g of CaCO3reacts with 44g of CO2 at s.t.p. i.e 22.4 dm3
2g of CaCO3 will react with (2*22.4)/100 of CO2 = 0.448 dm3
0.448 dm3 = 0.448 * 1000 = 448cm3
5.

According to charles' law, the volume of a gas becomes zero at

A. 0 oC

B. -100 oC

C. -273 oC

D. -373 oC

C

6.

It is difficult to achieve an orderly arrangement of the molecules of a gas because they

A. have no definite shape

B. have little force of attraction between them

C. can collide with one another in the container

D. are too small in size

C

7.

A given volume of methane diffuses in 20s. How long will it take the same volume of sulphur (IV) oxide to diffuse under the same conditions?
[C = 12, H = 1, S = 32, O = 16

A. 5s

B. 20s

C. 40s

D. 60s

Detailed Solution

Relative molecular mass of CH4 = 12 * 1 + 4 = 16
Relative molecular mass of SO2 = 32 + 10 *2 = 64
tSO2/tCH4 = √MSO2/MCH4
t/20 = √64/16 = √4
t/20 = 2
∴ t = 20 * 2 = 40sec
8.

An electron can be added to a halogen atom to form a halide ion with

A. 2 valence electrons

B. 3 valence electrons

C. 7 valence electrons

D. 8 valence electrons

D

9.

The shape of s-orbitals is

A. spherical

B. elliptical

C. spiral

D. circular

A

10.

22688Ra → x86Rn + α - particle
What is the value of x in the nuclear reaction above?

A. 220

B. 222

C. 226

D. 227

Detailed Solution

22688Ra → 22286Rn + α - particle