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.

391.

Stoichiometry is based on the law?

A.

multiple proportion

B.

constant composition

C.

conservation of energy

D.

conservation of mass

Correct answer is D

The principles of stoichiometry are based upon the law of conservation of mass. Matter can neither be created nor destroyed, so the mass of every element present in the product(s) of a chemical reaction must be equal to the mass of each and every element present in the reactant(s).

392.

How many moles of carbon(iv)oxide contains 16.0g of oxygen?

[ C = 12.0, O = 16.0 ]

A.

0.20 mol

B.

0.25 mol

C.

0.40 mol

D.

0.50 mol

Correct answer is D

1 Mole of carbon(iv)oxide contains 32g of Oxygen

: 0.5 Mole of carbon(iv)oxide contains 16g of Oxygen

393.

When an equilibrium is established between dissolved and undissolved solutes, the solution is said to be?

A.

Saturated

B.

Unsaturated

C.

Concentrated

D.

Diluted

Correct answer is A

The term saturated solution is defined in chemistry as a solution in which no more solute can be dissolved in the solvent.

394.

Which of the following pairs of components have the same molecular mass?

[ H = 1.0, C = 12.0, O = 16.0 ]

A.

Ethene and Ethyne

B.

Ethane and Ethene

C.

Carbon (ii) Oxide and Ethene

D.

Carbon (iv) Oxide and Ethyne

Correct answer is C

Ethene = 28

Ethyne = 26

Carbon(ii)Oxide = 28

Carbon(iv)Oxide = 44

395.

Which of the substances is non-polar?

A.

Bromine

B.

Ammonia

C.

Water

D.

Hydrogen Bromide

Correct answer is A

 Br2 (Bromine) is nonpolar because, in this molecule, both bromine atoms have the same electronegativity due to which both atoms have equal charge distribution and results in a net-zero dipole moment.