$A$ gas sample of $1.47 \ L$ was collected over water at $30 \ ^\circ C$ and $744 \ mm \ Hg$ pressure. If the weight of the gas is $1.98 \ g$,what is the molar mass of the gas? (Assume the vapor pressure of water at $30 \ ^\circ C$ is $31.8 \ mm \ Hg$)

When a sample of gas is compressed at constant temperature from $15 \, atm$ to $60 \, atm$,its volume changes from $76 \, cm^3$ to $20.5 \, cm^3$. Which of the following statements are possible explanations of this behaviour?
$(1)$ The gas behaves non-ideally
$(2)$ The gas dimerises
$(3)$ The gas is adsorbed into the vessel walls

Which of the following statements is correct?

The normal boiling point of water is $373 \ K$ (at $760 \ mm$). The vapor pressure of water at $298 \ K$ is $23 \ mm$. If the enthalpy of vaporization of water is $40.656 \ kJ/mol$,then the boiling point of water at $23 \ mm$ pressure will be ........... $K$.

$A$ $4 : 1$ molar mixture of $He$ and $CH_4$ is kept in a vessel at $20 \ bar$ pressure. Due to a hole in the vessel,the gas mixture leaks out. What is the composition of the mixture effusing out initially?

Two flasks $I$ and $II$ shown below are connected by a valve of negligible volume. When the valve is opened,the final pressure of the system in bar is $x \times 10^{-2}$. The value of $x$ is $.....$ . (Integer answer) [Assume-Ideal gas; $1 \, bar = 10^{5} \, Pa$; Molar mass of $N_{2} = 28.0 \, g \, mol^{-1}$; $R = 8.31 \, J \, mol^{-1} \, K^{-1}$]