$A$ gas is contained in a closed vessel. The initial temperature of the gas is $100^{\circ} C$. If the pressure of the gas is increased by $4 \%$,what is the increase in the temperature of the gas (in $^{\circ} C$)?

The graph of four gases with the same number of moles is given. Then:

At a room temperature of $23^{\circ}C$,a person inhales $1500 \, ml$ of air at a body temperature of $37^{\circ}C$. If the pressure and mass remain constant,what will be the volume of the air in the person's lungs in $ml$?

If the intermolecular forces vanish away,the volume occupied by the molecules contained in $4.5 \,kg$ of water at standard temperature and pressure will be

In the relation $n = \frac{PV}{RT}$,what does $n$ represent?

$A$ long cylindrical pipe of radius $20 \,cm$ is closed at its upper end and has an airtight piston of negligible mass as shown. When a $50 \,kg$ mass is attached to the piston,it moves down. If the air in the enclosure is cooled from temperature $T$ to $T-\Delta T$,the piston moves back to its original position. Then $\Delta T / T$ is close to (Assuming air to be an ideal gas,$g=10 \,m/s^2$,atmospheric pressure is $10^5 \,Pa$)