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.

1,181.

An aqueous solution of Na2CO3 is

A.

acidic

B.

alkaline

C.

amphoteric

D.

neutral

Correct answer is B

No explanation has been provided for this answer.

1,182.

How many lone pair (s) of electrons is present in HF?

A.

0

B.

1

C.

2

D.

3

Correct answer is D

No explanation has been provided for this answer.

1,183.

NH4- is formed from NH3 and H- by

A.

covalent bonding

B.

dative bonding

C.

hydrogen bonding

D.

ionic bonding

Correct answer is B

No explanation has been provided for this answer.

1,184.

The relative atomic mass of chlorine is not a whole number because

A.

it is the weighted average mass of all its various isotopes

B.

it is the average mass of all the isotopes of the element

C.

the element has strong oxidizing ability

D.

the atom contains a higher number of neutrons than protons

Correct answer is B

Chlorine is a mixture of two isotopes with different abundances. Its relative atomic mass is the mean or average of the isotopic masses.

1,185.

An atom W has 17 electrons and 18 neutrons. Which of the following representations of the atom is correct?

A.

1718W

B.

1817W

C.

3517W

D.

3518W

Correct answer is C

The superscript is the atomic mass = 35

(The mass number also called atomic mass number or nucleon number, is the total number of protons and neutrons)

 

The subscript is the atomic or proton number = 17

The number of electrons in a neutral atom is equal to the number of protons