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

$A$ vessel contains $1.6 \ g$ of dioxygen at $STP$ ($273.15 \ K$,$1 \ atm$ pressure). The gas is now transferred to another vessel at constant temperature,where pressure becomes half of the original pressure. Calculate
$(A)$ volume of the new vessel.
$(B)$ number of molecules of dioxygen.

What will be the pressure exerted by a mixture of $3.2 \ g$ of methane and $4.4 \ g$ of carbon dioxide contained in a $9 \ dm^3$ flask at $27^{\circ} C$?

Density of a gas is found to be $5.46 \, g / dm^3$ at $27^{\circ} C$ at $2 \, bar$ pressure. What will be density at $STP$?

Dalton's law of partial pressure will not apply to which of the following mixtures of gases?

What is the relationship between the mass and volume of a gas?