Pressure of a gas in a vessel can be measured by

On a certain day,the humidity in the atmosphere is $1\%$. If the barometer reads $760 \ mm \ of \ Hg$,what will be the pressure of the dry gas in $mm \ of \ Hg$?

Under standard conditions of temperature and pressure,what will be the ratio of the rate of diffusion of helium to methane?

One atmosphere is equal to

$2.0 \ g$ of $H_2$ diffuses through a porous container in $10 \ minutes$. How many grams of $O_2$ would diffuse from the same container in the same time under similar conditions (in $.0$)?

Which of the following is not considered in the calculation of the rate of diffusion according to Graham's Law?