The rate of diffusion of $SO_{2}$,$CO_{2}$,$PCl_{3}$ and $SO_{3}$ are in the following order:

$A$ sample of air contains $N_2, O_2$ and $H_2O$. It is saturated with water vapor and the total pressure is $640 \, torr$. The vapor pressure of water is $40 \, torr$ and the molar ratio of gases ${N_2}:{O_2}$ is $3:1$. What is the partial pressure of $N_2$ in the sample in $torr$?

The total pressure exerted by a mixture of non-reacting gases is equal to the sum of the partial pressures of the individual gases under the same conditions. This is known as:

$A$ sample of air contains $N_2$ and $O_2$ saturated with water vapor,with a total pressure of $640 \ torr$. If the water vapor pressure is $40 \ torr$ and the molar ratio of $N_2$ to $O_2$ is $3 : 1$,what is the partial pressure of $N_2$ in the sample in $torr$?

Equal masses of helium and oxygen are mixed in an empty container at $25^{\circ} C$. What is the fraction of the total pressure exerted by helium?

The ratio of the rate of diffusion of a given element to that of helium is $1.4$. The molecular weight of the element is