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.

131.

Which noble gas is radioactive and is produced as a decay product of uranium and thorium?

A.

Argon

B.

Krypton

C.

Radon

D.

Neon

Correct answer is C

Radon is a radioactive noble gas and is produced as a decay product of uranium and thorium in the Earth's crust. It is colorless, odorless, and tasteless, making it potentially hazardous when it accumulates in enclosed spaces.

132.

What happens to the position of equilibrium, if a reversible exothermic reaction is subjected to a decrease in temperature?

A.

The position of equilibrium shifts to the left

B.

The position of equilibrium shifts to the right.

C.

The position of equilibrium remains unchanged

D.

The reaction stops

Correct answer is B

When the temperature is decreased in a reversible reaction, the equilibrium shifts in the direction that produces heat (exothermic direction). For an exothermic reaction, this means the equilibrium position shifts to the right, favoring the forward reaction.

133.

Hard water is water with high concentrations of dissolved ions, in particular calcium and

A.

magnesium ions

B.

nitrogen ions

C.

phosporus ions

D.

helium ions

Correct answer is A

Hard water is water with high concentrations of dissolved ions, in particular calcium and magnesium ions

134.

Which of the following sketches is a graphical representation of Boyle's law?

A.

A

B.

B

C.

C

D.

D

Correct answer is C

Boyles law states that the volume of a given mass of gas is inversely proportional to pressure at constant temperature.

135.

Which of the following scientists formulated the law of conservation of mass?

A.

A. Lavoisier

B.

J. Dalton

C.

R. Boyle

D.

J. Proust

Correct answer is A

Law of conservation of mass was given by Antoine Lavoisier in 1744. According to this law, "Matter can neither be created nor destroyed in a chemical reaction".