Post Utme Chemistry Past Questions and Answers

Question 186:

An increase in temperature causes an increase in the pressure of a gas because there is an increase in the ____________

A. Average velocity of the gas molecules
B. Number of collisions between the gas molecules
C. Density of the gas. molecules
D. Free mean path between each molecule and the other

Question 187:

A liquid begins to boil when

A. Its vapour pressure is equal to the vapour pressure of its solid at a given temperature
B. Molecules start escaping from the surface
C. Its vapour pressure equals the atmospheric with pressure
D. Its volume is slightly increased

Question 188:

If the relative rate of diffusion of a gas is \(0.25\) and that of \(\mathrm{Cl}_{2}\) under the same conditions is \(0.20\), calculate the relative molecular mass of the gas.

A. \(22.7\)
B. \(45.4\)
C. \(68.1\)
D. \(90.8\)

Question 189:

The following molecules contain hydrogen bonding EXCEPT

A. Ammonia
B. Ethanoic acid
C. Hydrogen fluoride
D. Water

Question 190:

If \(20 \mathrm{~cm}^{3}\) of distilled water is added to \(80 \mathrm{~cm}^{3}\) of \(0.50 \mathrm{~mol} / \mathrm{dm}^{3}\) \(\mathrm{HCl}\) solution, the new concentration of the acid is ____________

A. \(0.10 \mathrm{~mol} / \mathrm{dm}^{3}\)
B. \(0.20 \mathrm{mnol} / \mathrm{dmi}^{3}\)
C. \(0.40 \mathrm{~mol} / \mathrm{dm}^{3}\)
D. \(2.00 \mathrm{~mol} / \mathrm{dm}^{3}\)