JAMB Past Questions and Answers - Page 1372

6,856.

Depreciation on a particular piece of machinery was N2,700 during the fifth year of its service life and N4,050 during the sixth year. The logical explanation for this is that?

A.

An addition was made to the asset during the sixth year

B.

The estimate of salvage value on this equipment was decreased

C.

A unit-of-output method of depreciation was used during the sixth year

D.

The estimate remaining service life of the assets was increased at the beginning of the sixth year

Correct answer is A

No explanation has been provided for this answer.

6,857.

A chemical reaction in which the hydration energy is greater than the lattice energy is referred to as

A.

A reversible reaction

B.

A spontenous reaction

C.

An endothermic reaction

D.

An exothermic reaction

Correct answer is D

In salts for which the hydration energy is higher than the lattice energy, solvation occurs with a release of energy in the form of heat. A reaction in which there is a release of energy as LIGHT OR HEAT is EXOTHERMIC.

6,858.

The gas that is used for the treatment of cancer is

A.

Neon

B.

Radon

C.

Xenon

D.

Argon

Correct answer is B

No explanation has been provided for this answer.

6,860.

Calculate the volume in cm3 of oxygen evolved at s.t.p when a current of 5A is passed through acidified water for 193s?
[F = 96500 C mol1. Molar volume of a gas at s.t.p = 22.4dm3]

A.

0.056dm3

B.

0.224dm3

C.

224.000dm3

D.

56.000dm3

Correct answer is A

Q = 193 x 5 = 965C
40H \(\mapsto\) 2H2O + O2 + 4e
4 x 96500C = 22.4dm3
965C = x

x = \(\frac{22.4 \times 965}{4 \times 96500}\)
= 0.056dm3