WAEC Chemistry Past Questions & Answers - Page 76

376.

Consider the following reaction equation:
C2H4(g) + 3O2(g) \(\to\) 2CO2(g) + 2H2O(g)

The volume of CO2(g) produced at s.t.p when 0.05 moles of C2H4(g) was burnt in O2(g) is
[Molar Volume of gas = 22.4dm3

A.

1.12dm3

B.

2.24dm3

C.

3.72dm3

D.

4.48dm3

Correct answer is B

\(\frac{\text{volume}}{\text{molar volume}}\) = 0.05

1 mole of ethane produces 2 moles of carbon(iv)oxide

∴ 0.05  mole of ethane will produce x moles of carbon(iv)oxide

= \(\frac{\text{volume}}{22.4}\) = 0.05 X 2 X 22.4 =  2.24dm\(_3\)

377.

Which of the following trioxonitrate(V) salts would decompose on heating to form a metal?

A.

Cu(NO3)2

B.

AgNO3

C.

Pb(NO3)2

D.

KNO3

Correct answer is B

No explanation has been provided for this answer.

378.
379.

Which of the following oxides is ionic?

A.

P4O10

B.

MgO

C.

Al2O3

D.

SO2

Correct answer is B

No explanation has been provided for this answer.

380.

The shape of a graphite crystal is

A.

Tetrahedral

B.

Pyramidal

C.

Octahedral

D.

Hexagonal

Correct answer is D

No explanation has been provided for this answer.