JAMB Chemistry Past Questions & Answers - Page 242

1,206.

Pure sulfuric acid is a liquid of 1.84 density. What volume of it would be required to prepare 250 cm3 of 2.0 M solution?


(H = 1, S = 32, O = 16)

A.

2.00

B.

2.66

C.

3.00

D.

3.66

E.

4.00

Correct answer is B

1000 cm3 of 1 m H2SO4 contains 98 gm of H2SO4
250 of 1 m H2SO4 (98)/(4) x (2)/(10) = 4.9 gm
But density = (mass)/(volume)
Volume = (Mass)/(Density) (4.90)/(1.84) = 2.66

1,207.

In the extraction of iron, which of the following reactions does NOT take place in the blast furnace?

A.

CO2 + C → 2CO

B.

2Fe2O3 + 3C → 4Fe + 3CO2

C.

Fe2O3 + 3C → 2Fe + 3CO2

D.

CaCO3 → CaO + CO2

E.

CaO + SiO2 → CaSiO3

Correct answer is B

No explanation has been provided for this answer.

1,208.

5cm3 of a saturated solution of sodium chloride at 30°C gave, on careful evaporation, 1.95g of solid salt. The solubility of sodium chloride at 30°C?

(Na = 23, Cl = 35.5)

A.

5.00 mole dm3

B.

5.67 mole dm3

C.

6.00 mole dm3

D.

6.67 mole dm3

E.

7.00 mole dm3

Correct answer is D

1.95 gms of NaCl dissolves in 5 cm solution at 30°C
Number of gm of solute required to dissolve in
100 gm = (1.950 x 100)/ (5 x 1) = 1.95 x 20 = 39.0
390 gms will dissolve in 1000 dm3
Solution
Solubility of NaCl at 30°C in
(dm3 is 390)/(Mol wt g NaCl) = 6.67 mol dm3

1,209.

The electronic configuration of elements X and Y are X = 2, 8, 6; Y = 2, 8, 7. The bond in the compound formed by X and Y is expected to be?

A.

ionic

B.

covalent

C.

dative covalent

D.

metallic

E.

none of the above

Correct answer is B

No explanation has been provided for this answer.

1,210.

Which of the following is NOT a true statement of the kinetic Theory of Gases?

A.

The molecules move at random

B.

The size of molecules is negligble as compared with the volume of gas

C.

The molecular collisions are perfectly elastic

D.

Every molecule has the same kinetic energy at a particular temperature

E.

The average kinetic energy is proportional to the absolute temperature of the gas

Correct answer is D

No explanation has been provided for this answer.