In the kinetic theory of gases,which of the following statements regarding elastic collisions of the molecules is wrong?

Two gases of equal mass are in thermal equilibrium. If $P_a, P_b$ and $V_a, V_b$ are their respective pressures and volumes,then which relation is true?

Statement-$1$: Internal energy of a gas $U = nC_VT$ is due to the random motion of gas molecules.
Statement-$2$: $A$ container is moving with speed $v$. It is suddenly stopped by a force,and the temperature of the gas increases.

An insulated system contains $4$ moles of an ideal diatomic gas at temperature $T$. When a heat $Q$ is supplied to the gas,$2$ moles of the gas is dissociated into atoms and the temperature remains constant. Then the relation between $Q$ and $T$ is ($R=$ universal gas constant.)

$A$ thermally isolated cylindrical closed vessel of height $8 \ m$ is kept vertically. It is divided into two equal parts by a diathermic (perfect thermal conductor) frictionless partition of mass $8.3 \ kg$. Thus,the partition is held initially at a distance of $4 \ m$ from the top. Each of the two parts of the vessel contains $0.1 \ mol$ of an ideal gas at temperature $300 \ K$. The partition is now released and moves without any gas leaking from one part of the vessel to the other. When equilibrium is reached,the distance of the partition from the top (in $m$) will be. . . . . . (take the acceleration due to gravity $g = 10 \ m/s^2$ and the universal gas constant $R = 8.3 \ J \ mol^{-1} \ K^{-1}$).

At a temperature of $300 \ K$,the average translational kinetic energy and $rms$ speed of a sample of oxygen gas are $6.21 \times 10^{-21} \ J$ and $484 \ m/s$ respectively. At $600 \ K$,these values will be respectively: (Assume ideal gas behavior)