WAEC Chemistry Past Questions & Answers - Page 154

766.

What is the value of -14oC on the Kelvin temperature scale?

A.

259K

B.

287 K

C.

287oK

D.

259oK

Correct answer is A

No explanation has been provided for this answer.

767.

What is the percentage by weight of calcium in Ca(OCI)2? [Ca = 40, Cl = 35.5, O = 16]

A.

28.0%

B.

31.6%

C.

43.8%

D.

44.5%

Correct answer is A

No explanation has been provided for this answer.

769.

How many molecules are there in 14 g of nitrogen at s.t.p.? [N = 14, Avogadro's constant = 6.02 x 1023 mol-1]

A.

6.02 x 1023

B.

3.01 x 1023

C.

8.43 x 1024

D.

1.20 x 1024

Correct answer is A

No explanation has been provided for this answer.

770.

The number of particles in one mole of a chemical compound is the

A.

atomic number

B.

avogadro's number

C.

mass number

D.

oxidation number

Correct answer is B

No explanation has been provided for this answer.