$A$ diatomic molecule has how many degrees of freedom?

Consider a gas of triatomic molecules. The molecules are assumed to be triangular and made of massless rigid rods whose vertices are occupied by atoms. The internal energy of a mole of the gas at temperature $T$ is $......RT$.

If hydrogen gas is heated to a very high temperature,then the fraction of energy possessed by gas molecules corresponding to rotational motion is ...........

According to the law of equipartition of energy, the molar specific heat of a non-rigid diatomic gas at constant volume is

$A$ container holds $1 \, \text{mole}$ of oxygen and $2 \, \text{moles}$ of nitrogen at a temperature of $300 \, K$. What is the ratio of the average rotational kinetic energy of $O_2$ to that of $N_2$?

At standard temperature and pressure $(STP)$,the density of a gas is $1.3 \ kg/m^3$ and the speed of sound in the gas is $330 \ m/s$. The degree of freedom of the gas is: