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.

151.

Which of the following bond types is intermolecular?

A.

Covalent bond

B.

Hydrogen bond

C.

Ionic bond

D.

Metallic bond

Correct answer is B

Hydrogen bond is an intermolecular force which arises when hydrogen is covalently linked to elements like nitrogen, oxygen and fluorine.

152.

What is the percentage composition of carbon
in Ca(HCO3)\(_{2}\) ?
[ Ca = 40.0, 0= 16.0, C = 12.0, H= 1.0]

A.

22.2%

B.

14.8%

C.

7.4%

D.

3.7%

Correct answer is B

. % of C in Ca(HCO3)2
Molar mass of Ca(HCO3)2 = 40+(1+12+(16*3))2
=40+(13+48)2
=40+122
=162
C/Ca(HCO3)2 x 100
=12 * 2/162 * 100
=14.8%

153.

Which of the following elements would displace copper from a solution of copper ions?

A.

silver

B.

gold

C.

lead

D.

mercury

Correct answer is C

The reactivity series allows us to predict how metals react. A more reactive metal displaces a less reactive metal from a compound. Lead is more reactive metal than copper hence, copper is displaced from copper solution by lead.

154.

If 50 cm\(^{3}\) of a saturated solution of KNO\(_{3}\) at 40 °C contained 5.05 g of the salt, its solubility at the same temperature would be
[KNO\(_{3}\) = 101]

A.

1.0 mol dm\(^{-3}\)

B.

1.5 mol dm\(^{-3}\)

C.

2.0 mol dm\(^{-3}\)

D.

5.0 mol dm\(^{-3}\)

Correct answer is A

V= 50cm\(^{3}\)
Mass= 5.05g
Relative molecular mass of KNO\(_{3}\) = (39+14+(3*16)) = 101
Convert 50cm\(^{3}\) to dm\(^{3}\) which is
1000cm³ = 1dm\(^{3}\)
50cm³ = 50*1/1000
= 0.05dm\(^{3}\)
Moles = mass/ molar mass
= 5.05/101 =0.05mole
Solubility= mole/volume
Solubility=0.05mol/0.05dm\(^{3}\)
Solubility=1.0mol/dm_\(^{3}\)

155.

What number of moles of oxygen would exert a pressure of 10 atm at 320 K in an 8.2 dm\(^{3}\) cylinder?
[R=0.082 atm dm\(^{-3}\) mol\(^{-1}\) K\(^{-1}\)]

A.

0.32

B.

1.52

C.

3.13

D.

31.25

Correct answer is C

P = 10atm, T= 320K, V= 8.2dm\(^{3}\)
PV =nRT
n = P * V/R * T
10 * 8.2/0.082 * 320
= 82/26.24
n = 3.13