If the four tubes of a car are filled to the same pressure with $N_2$,$O_2$,$H_2$ and $Ne$ separately,then which one will be filled first?

The mass of molecule $A$ is half the mass of molecule $B$. The $rms$ speed of $A$ is twice the $rms$ speed of $B$. If the number of molecules in samples of $A$ and $B$ are equal,what is the ratio of the pressures of samples $A$ and $B$ in separate containers of equal volume?

Liquids diffuse more slowly than gases because.....

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 $K$)?

Two gases $A$ and $B$ are released from the two ends of a tunnel of length $100 \ m$. $A$ travels $40 \ m$ before meeting the gas $B$ in the tunnel. If the molecular weight of $B$ is $18$, what is the molecular weight of $A$ (in $.5$)?

What is the average translational kinetic energy of a gas molecule?