What is the compressibility factor of an ideal gas?

$A$ container is filled with nitrogen gas at a certain temperature and pressure. The mass of the gas is $0.6 \ g$. Now,the container is filled with another gas at the same temperature and pressure. If the mass of the second gas under the given conditions is $0.73 \ g$,identify the gas.

$A$ gas at a pressure of $2 \ atm$ is heated from $25^{\circ} C$ to $323^{\circ} C$ and simultaneously compressed to $\frac{2}{3}$ of its original volume. What is the final pressure (in $atm$)?

If $500 \ cm^3$ of hydrogen gas is at a pressure of $760 \ mm$ and a temperature of $300 \ K$,what is the number of moles?

Containers $A$ and $B$ contain the same gas. If the pressure,volume,and temperature of container $A$ are all twice those of container $B$,what is the ratio of the number of molecules in $A$ to those in $B$?

In a $1 \ L$ flask,$N_2$ gas is at $100 \ kPa$ pressure,and in another $3 \ L$ flask,$O_2$ gas is at $320 \ kPa$ pressure. If both flasks are connected,what will be the resultant pressure in $kPa$?