WAEC Past Questions and Answers - Page 1292

6,456.

The following steps are scientific methods except

A.

experimentation

B.

problem identification

C.

Analysis

D.

Open-mindedness

Correct answer is D

From the given options, "Open-mindedness" is not a specific step in the scientific method. Open-mindedness is a general mindset that scientists should have throughout the entire process. It involves being receptive to new ideas, evidence, and interpretations, which helps scientists avoid biases and reach more accurate conclusions.

6,457.

Which of the following reactions represents the hydrolysis of an alkanoate?

A.

\(CH_3COOH + OH^- ⇌H^+⇌ CH_3COO^- + H_2O\)

B.

\(CH_3COOH + C_2H_5OH ⇌H^+⇌ CH_3COOC_2H_5 + H_2O\)

C.

\(CH_3COOC_2H_5 + H_2O ⇌H^+⇌ CH_3COO^- + CH_3CH_2OH\)

D.

\(CH_3COOCH_2CH_3 + H_2O ⇌H^+⇌ CH_3COOH + CH_3CH_2OH\)

Correct answer is D

The hydrolysis of an alkanoate is the reaction of an alkanoate with water to form a carboxylic acid and an alcohol. The correct reaction is:

\(CH_3COOC_2H_5 + H_2O ⇌H^+⇌ CH_3COOH + CH_3CH_2OH\)

6,458.

The following statements are correct except

A.

energy is released when liquids change to solids.

B.

carbon atoms in gaseous methane are further apart than those in solid diamond.

C.

there is large decrease in the volume of a solid metal when pressure is applied to it.

D.

particles move faster in the gaseous state than in the liquid state.

Correct answer is C

In general, solids are relatively incompressible compared to liquids and gases. When pressure is applied to a solid, there is typically only a small change in volume. Solids have tightly packed particles with strong intermolecular forces, making them less responsive to changes in pressure. Liquids and gases, on the other hand, can undergo larger volume changes in response to pressure.

6,459.

The vapour density of an organic compound with the molecular formula \(C_2H_4O_2\), is
[H=1.0, C=12.0, O= 16.0]

A.

40

B.

120

C.

65

D.

30

Correct answer is D

Molar mass of \(C_2H_4O_2\),= (12 × 2) + (1 × 4) + (16 × 2)= 60 g/mol
Vapour density = RMM/2
=60/2=30

6,460.

Which of the following is a nominal account?

A.

Machinery account

B.

Drawings account

C.

Debtors account

D.

Wages account

Correct answer is D

No explanation has been provided for this answer.