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

$A$ closed vessel contains an equal number of nitrogen and oxygen molecules at a pressure of $P \ mm$. If nitrogen is removed from the system,then the pressure will be

When $0.0168 \ mol$ of $O_2$ obtained from the decomposition of $KClO_3$ is collected over water at $25 \ ^oC$,the volume is $428 \ mL$ and the total pressure is $754 \ mm$. What is the aqueous tension (water vapor pressure) at $25 \ ^oC$ in $mm$?

Sulphur dioxide $(SO_2)$ and oxygen $(O_2)$ were allowed to diffuse through a porous partition. $20 \ dm^3$ of $SO_2$ diffuses through the porous partition in $60 \ seconds$. The volume of $O_2$ in $dm^3$ which diffuses under the similar conditions in $30 \ seconds$ will be (atomic mass of sulphur $= 32 \ u$)

The temperature at which the vapor pressure of a liquid becomes equal to the atmospheric pressure is called.....

The atomic masses of carbon,nitrogen,and oxygen are $12, 14$,and $16$ respectively. Which of the following pairs of gases will diffuse at the same rate?