An open vessel containing air was heated from $27^{\circ} C$ to $727^{\circ} C$. Some air was expelled. What is the fraction of air remaining in the vessel? (Assume air as an ideal gas)

$A$ home owner uses $4.00 \times 10^{3} \ m^{3}$ of methane $(CH_{4})$ gas (assume $CH_{4}$ is an ideal gas) in a year to heat his home. Under the pressure of $1.0 \ atm$ and $300 \ K$,the mass of gas used is $X \times 10^{5} \ g$. The value of $X$ is $.......$ (Nearest integer).
(Given $R = 0.083 \ L \ atm \ K^{-1} \ mol^{-1}$)

$A$ $10 \ g$ of a gas at atmospheric pressure is cooled from $273 \ ^oC$ to $0 \ ^oC$ keeping the volume constant,its pressure would become ............. $atm$.

One litre of a gas weighs $2 \ g$ at $300 \ K$ and $1 \ atm$ pressure. If the pressure is made $0.75 \ atm$,at which of the following temperatures will one litre of the same gas weigh $1 \ g$?

$A$ container is divided into two equal parts $A$ and $B$ containing $H_2$ and $O_2$ respectively,each at $1 \ atm$ pressure. If the wall separating the two sections is removed,what happens to the pressure?

At what temperature in $K$ will $28 \ g$ of $N_2$ gas occupy a volume of $10.0 \ L$ at $2.46 \ atm$ pressure?