At a given temperature,the pressure of an ideal gas of density $\rho$ is proportional to

The pressure $P$,volume $V$,and temperature $T$ of a gas in jar $A$ are given. Another gas in jar $B$ has pressure $2P$,volume $V/4$,and temperature $2T$. The ratio of the number of molecules in jar $A$ to jar $B$ is:

Which one of the following represents correctly the variation of volume $(V)$ of an ideal gas with temperature $(T)$ under constant pressure conditions?

Which of the following graphs represents the behavior of an ideal gas? Symbols have their usual meaning.

At the top of a mountain,a thermometer reads $7^{\circ}C$ and a barometer reads $70 \, cm$ of $Hg$. At the bottom of the mountain,these read $27^{\circ}C$ and $76 \, cm$ of $Hg$ respectively. The ratio of the density of air at the top to that at the bottom is

$A$ cylinder of volume $30 \, L$ contains oxygen at an initial gauge pressure of $15 \, atm$ and a temperature of $27^{\circ}C$. After some oxygen is withdrawn from the cylinder,the gauge pressure drops to $11 \, atm$ and its temperature drops to $17^{\circ}C$. The mass of oxygen taken out of the cylinder is approximately ........ $kg$. (Given: $R = 8.31 \, J \, mol^{-1} K^{-1}$,molar mass of $O_2 = 32 \, g/mol$ or $32 \times 10^{-3} \, kg/mol$)