At what temperature does the volume of a gas become theoretically zero?

Which relation represents the change in density of an ideal gas with changes in temperature and pressure?

In the equation $PV = nRT$,which of the following is not equal to the numerical value of $R$?

At $300 \ K$,a sample of $3.0 \ g$ of gas $A$ occupies the same volume as $0.2 \ g$ of hydrogen $(H_2)$ at $200 \ K$ at the same pressure. The molar mass of gas $A$ is $...... \ g \ mol^{-1}$ (nearest integer). Assume that the gases behave as ideal gases.

$A$ dry gas occupies $136.5 \, cm^3$ at $STP$. If the same mass of gas is collected over water at $27 \, ^oC$ and a total pressure of $725 \, torr$,what volume will it occupy in $cm^3$? (Vapour pressure of water at $27 \, ^oC$ is $25 \, torr$.)

Calculate the final volume of a gas when the pressure of $60 \ mL$ of gas is increased from $1 \ atm$ to $1.5 \ atm$,keeping the temperature constant.