Chemistry questions and answers

Chemistry Questions and Answers

Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.

551.

A 0.1\(moldm^{-3}\) solution of sodium hydroxide was diluted with distilled water to 0.001\(moldm^{-3}\). What is the dilution factor?

A.

1000.00

B.

100.00

C.

10.00

D.

0.01

Correct answer is D

Dilution factor = \(\frac{molar conc. of diluted}{molar conc. of undiluted}\)

= \(\frac{0.001}{0.1} = 0.01\)

552.

Which of the following statements about endothermic reaction is correct?

A.

Activation energy is high

B.

A catalyst is required

C.

It occurs reversibly

D.

Heat energy is absorbed

Correct answer is D

Endothermic reactions are those reactions which absorb energy from the surroundings and result in a net decrease in temperature.

553.

The use of diamond in abrasives is due to its

A.

high melting point

B.

hardness

C.

octahedral shape

D.

durability

Correct answer is B

Diamonds are very hard, they are often used as an abrasive.

554.

The properties of a good primary standard include the following except

A.

high molecular mass

B.

low molecular mass

C.

high degree of purity

D.

readily available

Correct answer is B

Characters of a good primary standard include: high purity, low reactivity with the air or surrounding environment, low hygroscopicity, large molar mass, a predictable reactivity and readily available.

555.

The bond angle in tetrahedral molecules such as tetrachloromethane is 

A.

180.0°

B.

109.5°

C.

105.5°

D.

90.0°

Correct answer is B

No explanation has been provided for this answer.