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

On what factors does the vapor pressure of a liquid depend?

If the rate of diffusion of $A$ is $5$ times the rate of diffusion of $B$,what will be the ratio of the densities of $A$ and $B$?

$A$ mixture of one mole each of $H_2$,$He$ and $O_2$ are enclosed in a cylinder of volume $V$ at temperature $T$. If the partial pressure of $H_2$ is $2 \ atm$,the total pressure of the gases in the cylinder is $....... \ atm$

Two gases $A$ and $B$ having the same volume diffuse through a porous partition in $20$ and $10$ seconds respectively. The molecular mass of $A$ is $49 \ u$. The molecular mass of $B$ will be .............. $u$.

Pressure cooker reduces cooking time for food because