At what temperature $K$ will the kinetic energy of $0.3 \ mol$ of $He$ be equal to the kinetic energy of $0.4 \ mol$ of $Ar$ at $400 \ K$?

One mole of an ideal gas at $300 \ K$ is expanded isothermally from $1 \ L$ to $10 \ L$ volume. $\Delta U$ for this process is $....... \ J$ (Use $R = 8.314 \ J \ K^{-1} \ mol^{-1}$)

If the density of gas $A$ is $1.5$ times that of gas $B$,and the molecular mass of $A$ is $M$,then the molecular mass of $B$ is:

At $27^{\circ} C$ in a $10 \ L$ flask,$4.0 \ g$ of an ideal gaseous mixture containing $He$ (molar mass $4.0 \ g \ mol^{-1}$) and $Ne$ (molar mass $20 \ g \ mol^{-1}$) has a pressure of $1.23 \ atm$. What is the mass $\%$ of neon? $(R = 0.082 \ L \ atm \ K^{-1} \ mol^{-1})$

If $R = 8.314$,express it with its units.

The density of Neon will be highest at