Loading [MathJax]/jax/output/HTML-CSS/jax.js

WAEC Chemistry Past Questions & Answers - Page 87

431.

The energy value of petrol can be determined by

A.

Bomb calorimeter

B.

Catalytic cracker

C.

Fractionating column

D.

Thermometer

Correct answer is C

Fractionating column contains petrol with different densities.

432.

The basic particles from which matter could be made up of are as follow, except?

A.

Salt

B.

Atom

C.

Ion

D.

Molecule

Correct answer is A

Salt is a chemical used for varieties of purposes, so it’s not part of matter, Atom being the smallest part of molecule and ion are charge which are part of matter

433.

The number of isomers formed by C6H14 is

A.

4

B.

5

C.

2

D.

3

Correct answer is B

The number of isomers C6H14 cm is 5. it will not form options A,C, D

434.

Cu2S(s)+O2(g)=2CU(s)+SO2(g).

In the above reaction, the oxidation number of Cu changes from ___ to _______?

A.

+1 to 0

B.

0 to +2

C.

+2 to +1

D.

0 to +1

Correct answer is A

The oxidation number is from +1 to O as a result of the release of sulphur. Options B, C, and D are not the actual oxidation number for copper

435.

All these are electromagnetic waves except

A.

White light

B.

Photon

C.

X-ray

D.

Infrared

Correct answer is B

Photon is unit of energy that carries light and has zero mass A, C and D are all electromagnetic waves of higher mass