WAEC Past Questions and Answers - Page 1347

6,731.

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

6,732.

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.

6,733.

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

6,734.

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.

6,735.

Calcium and magnesium belong to the group of the periodic table because both?

A.

are metals

B.

form cations

C.

form colourless salts

D.

have same number of valence electrons

Correct answer is D

No explanation has been provided for this answer.