What is meant by payload?

Which factors can cause a change in the physical states of matter?

According to Graham's law of diffusion at a given temperature,the ratio of the rate of diffusion $r_A/r_B$ for gases $A$ and $B$ is given by:

At $400 \ K$ temperature in a closed vessel,the $\%$ by volume of $He, Ne$,and $Ar$ are $40\%, 40\%$,and $20\%$ respectively. If the total pressure is $25 \ bar$,find the partial pressure of each gas.

Pressure-volume $(pV)$ work done by an ideal gaseous system at constant volume is (where $E$ is internal energy of the system):

$A$ mixture of $N_2$ and $Ar$ gases in a cylinder contains $7 \ g$ of $N_2$ and $8 \ g$ of $Ar$. If the total pressure of the mixture of gases in the cylinder is $27 \ bar$,the partial pressure of $N_2$ is $......... \ bar$.
[Use atomic masses (in $g \ mol^{-1}$) : $N=14, Ar=40$]