What is an elastic molecular collision?

What is the temperature at which the kinetic energy of $0.3 \ mol$ of helium is equal to the kinetic energy of $0.4 \ mol$ of argon at $400 \ K$ (in $K$)?

The kinetic theory of gases predicts that the total kinetic energy of a gaseous assembly depends on

According to the kinetic molecular theory of gases, which of the following statements are correct?
$a$) The actual volume of the molecules is negligible in comparison to the empty space between them.
$b$) Collisions of gas molecules are inelastic.
$c$) At any particular time, different particles in the gas have the same speed and same kinetic energies.
$d$) Pressure is exerted by the gas as a result of the collision of the particles with the walls of the container.

At $27^{\circ} C$ kinetic energy of $4 \ g$ of $H_2$ is $x \ J$. What is the kinetic energy (in $J$) of $6.4 \ g$ of oxygen at $127^{\circ} C$?

If a gas expands at constant temperature,it indicates that