Dry air at sea level contains $75.5\%\, N_2$ by mass. If the total atmospheric pressure is $1 \,atm$,the partial pressure of nitrogen is approximately $... \,atm$.

When the pressure on $1200 \ ml$ of a gas is increased from $70 \ cm$ to $120 \ cm$ of mercury at constant temperature,the new volume of the gas will be ........ $ml$.

$A$ 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 $^{\circ} C$)?

One mole of a perfect gas in a cylinder fitted with a piston has a pressure $P,$ volume $V,$ and temperature $T.$ If the temperature is increased by $1 \, K$ keeping pressure constant,the increase in volume is

The following graph represents the $T-V$ curves of an ideal gas (where $T$ is the temperature and $V$ is the volume) at three pressures $P_1, P_2$ and $P_3$ compared with those of Charles's law represented as dotted lines. Then the correct relation is:

Estimate the total number of air molecules (inclusive of oxygen,nitrogen,water vapour,and other constituents) in a room of capacity $25.0 \; m^{3}$ at a temperature of $27^{\circ} C$ and $1 \; atm$ pressure.