The density of air is higher at sea level. This fact is a practical application of which law?

At $300\, K$,the density of a certain gaseous molecule at $2\, bar$ is double that of dinitrogen $(N_2)$ at $4\, bar$. The molar mass of the gaseous molecule is ............... $g\, mol^{-1}$.

At $298 \, K$ temperature,$4 \, g$ of $H_2$ gas is filled in a $500 \, mL$ vessel. Due to a small hole in the vessel,after some time,the pressure in the vessel becomes $50 \, bar$. Find the number of $H_2$ molecules that have escaped from the vessel? $(R = 8.314 \times 10^{-2} \, L \, bar \, mol^{-1} \, K^{-1})$

The temperature of $1 \, mol$ of a gas is increased by $2 \, ^oC$ at constant pressure. The work done will be:

An open vessel at $27\,^{\circ}C$ is heated until $3/5$ of the air in it has been expelled. Assuming the pressure remains constant,what is the final temperature of the vessel in $^{\circ}C$?

In a $1 \ L$ flask,$N_2$ gas is at $100 \ kPa$ pressure,and in another $3 \ L$ flask,$O_2$ gas is at $320 \ kPa$ pressure. If both flasks are connected,what will be the resultant pressure in $kPa$?