State Gay-Lussac's Law of Gaseous Volumes.

What is the number of molecules in $1 \, litre$ of an ideal gas at $S.T.P.$?

$A$ container $AB$ in the shape of a rectangular parallelepiped of length $5 \,m$ is divided internally by a movable partition $P$ as shown in the figure. The left compartment is filled with a given mass $m$ of an ideal gas of molar mass $M_1 = 32$ while the right compartment is filled with an equal mass $m$ of another ideal gas of molar mass $M_2 = 18$ at the same temperature. What will be the distance of $P$ from the left wall $A$ when equilibrium is established (in $\,m$)?

An ideal gas at atmospheric pressure has a temperature of $300 \,K$ and a volume of $1 \,m^3$. If its temperature and volume are both doubled,its pressure will be ...........

Three containers of the same volume contain three different gases. The masses of the molecules are $m_1, m_2$ and $m_3$ and the number of molecules in their respective containers are $N_1, N_2$ and $N_3$. The gas pressures in the containers are $P_1, P_2$ and $P_3$ respectively. All the gases are now mixed and put in one of the containers. The pressure $P$ of the mixture will be

The equation of state for $5 \, g$ of oxygen at a pressure $P$ and temperature $T$,when occupying a volume $V$,will be (where $R$ is the gas constant).