What are the measurable properties of a gas?

If three unreactive gases having partial pressures $P_A$,$P_B$,and $P_C$ and their moles are $1$,$2$,and $3$ respectively,then their total pressure will be:

Which physical property decreases with an increase in intermolecular forces?

The ratio $\gamma$ for inert gases is

The rate of diffusion of two gases $x$ and $y$ is $10 \ mL/sec$ and $40 \ mL/sec$ respectively. The ratio of their molar masses $(Mw)_{x} : (Mw)_{y}$ is:

$A$ vessel of $2.461 \ L$ contains a mixture of $0.3 \ mol$ of $N_2$,$0.5 \ mol$ of $He$,and $6.2 \ mol$ of $O_2$ at $27 \ ^oC$. What is the partial pressure of $N_2$ in the mixture in $atm$?