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.

2,656.

Which of the following is used in fire extinguishers?

A.

Carbon (ll) oxide

B.

Carbon (lV) oxide

C.

Sulphur (lV) oxide

D.

Ammonia

Correct answer is B

No explanation has been provided for this answer.

2,657.

Which property of a reversible reaction is affected by a catalyst?

A.

Heat content (enthalphy)

B.

Energy of activation

C.

Free energy change

D.

Equilibrium position

Correct answer is B

No explanation has been provided for this answer.

2,658.

Which of the followingstatements is TRUE?

A.

The dissolution of NaOH(s) in water is endothermic

B.

The heat os solution of NaOH(s) is positive

C.

The NaOH(s) gains heat from the surroundings

D.

The heat of solution of NaOH(s) is negative

Correct answer is D

No explanation has been provided for this answer.

2,659.

Which of the following will produce the greatest increase in the rate of the chemical reaction represented by the equation Na2S2O3(aq) + 2HCl(aq) → 2NaCI(aq) + H2O(I) + SO2(g) + S(g)?

A.

A decrease in temperature and an increase in the concentration of the reactants

B.

An increase in the temperature and a decrease in the cocentration of the reactants

C.

An increase in temperature and an increase in the concentration of the reactants

D.

A decrease in the temperature and a decrease in the concentration of the reactants

Correct answer is C

No explanation has been provided for this answer.

2,660.

A mixture of starch solution and potassium iodide was placed in a test tube. On adding dilute tetraoxosulphate (lV) acid and then K2Cr2O7 solutions, a blue-black colour was produced. In this reaction, the?

A.

iodide is oxidized

B.

tetraoxosulphate (Vl) acid acts as an oxidizing agent

C.

starch has been oxidized

D.

K2Cr2O7 is oxidized

Correct answer is C

No explanation has been provided for this answer.