Processing math: 80%
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.

811.

Chemicals that are produced in small quantities and with very degree of purity are

A.

Bulk chemicals

B.

Fine chemicals

C.

Heavy chemicals

D.

Light chemicals

Correct answer is B

No explanation has been provided for this answer.

812.

The boiling points of HF, H2O and NH3 increase in the order of

A.

NH3

B.

H2O < HF

C.

HF < NH3 < H2O

D.

NH3 < HF < H2O

Correct answer is D

Ammonia = -33.34°C;  Hydrogen fluoride = 19.5°C; Water = 100°C

813.

When element 20Y combines with element 8Z, it forms

A.

A covalent compound , YZ is formed

B.

A covalent compound, ZY is formed

C.

An ionic compound, YZ is formed

D.

An ionic compound, ZY is formed

Correct answer is C

Y = 2,8,8,2 and Z = 2,6.

Y will readily give off its 2 valence electrons and Z will accept the 2 electrons in order to achieve octet configuration. Hence, the compound YZ is formed by ionic bonding.

814.

How many electrons are present in 94Be2+?

A.

2

B.

4

C.

5

D.

6

Correct answer is A

Neutral Be has 4 electrons but Be2+ means it has lost two electrons from possible four and became a positive ion. 

the number of electrons left will be equal to two.

815.

An atom X consist of 6 protons, 6 electrons and 7 neutrons. Which of the following representations of the atom is correct?

A.

136X

B.

137X

C.

196X

D.

197X

Correct answer is A

No explanation has been provided for this answer.