JAMB Chemistry Past Questions & Answers - Page 387

1,931.

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

Correct answer is B

In most cases, there are essentially no attractive forces between particles. This means that a gas has nothing to hold a specific shape or volume.

1,932.

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

A.

0 oC

B.

-100 oC

C.

-273 oC

D.

-373 oC

Correct answer is C

No explanation has been provided for this answer.

1,933.

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

Correct answer is C

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

1,934.

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

Correct answer is B

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

1,935.

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

Correct answer is D

No explanation has been provided for this answer.