If $P$ is pressure and $\rho$ is density of a gas,then $P$ and $\rho$ are related as

An ideal gas expands isothermally and reversibly from $10 \ m^3$ to $20 \ m^3$ at $300 \ K$,performing $5.187 \ kJ$ of work on the surroundings. Calculate the number of moles of gas used.

The volume of a given mass of a gas is directly proportional to its Kelvin temperature at constant pressure. The above statement is known as . . . . . .

An ideal gas with a molar mass of $40 \ g \ mol^{-1}$ has a mass of $120 \ g$. It occupies a volume of $20 \ L$ at a temperature of $400 \ K$. Using $R = 0.0821 \ L \ atm \ K^{-1} \ mol^{-1}$,the pressure of the gas is ........ $atm$.

Which of the following statements is incorrect?

Calculate the volume in liters for $7 \ g$ of $O_2$ gas at $27 \ ^\circ C$ and $750 \ mm$ of $Hg$ pressure.