Question

The molar heat capacity of oxygen gas at STP is nearly 2.5 R. As the temperature is increased, it gradually increases and approaches 3.5 R. The most appropriate reason for this behaviour is that at high temperatures
(a) oxygen does not behave as an ideal gas
(b) oxygen molecules dissociate in atoms
(c) the molecules collide more frequently
(d) molecular vibrations gradually become effective

Answer 1

The correct answer is option (d), which is the vibrations of the molecule become effective gradually.

Explanation:

• On the degree of gas molecules’ freedom, it is noted that molar specific heat capacity has a direct requirement.
• When there is an increase in the temperature, there will be a beginning wherein the gas molecules vibrate around their mean position, which leads to the change in the freedom’s degree, that is increase in the freedom’s degree and, thus, leading to the increase in the molar heat capacity.

Answer 2

Answer:

D as at high temperature vibratory degree of freedom will also be counted which is actually responsible for the increase in molar heat capacity.