What will be the value of the gas constant $R$ when pressure is expressed in $dyne \, m^{-2}$ and volume in $mm^3$?

$A$ box contains $0.90 \ g$ of liquid water in equilibrium with water vapour at $27^{\circ} C$. The equilibrium vapour pressure of water at $27^{\circ} C$ is $32.0 \ Torr$. When the volume of the box is increased,some of the liquid water evaporates to maintain the equilibrium pressure. If all the liquid water evaporates,then the volume of the box must be $.... \ litre$. [nearest integer]
(Given $R = 0.082 \ L \ atm \ K^{-1} \ mol^{-1}$)
(Ignore the volume of the liquid water and assume water vapours behave as an ideal gas.)

Two closed vessels of equal volume containing air at pressure $P_1$ and temperature $T_1$ are connected to each other through a narrow tube. If the temperature in one of the vessels is now maintained at $T_1$ and that in the other at $T_2$,what will be the final pressure in the vessels?

$34.05 \ mL$ of phosphorus vapor weighs $0.0625 \ g$ at $546 \ ^oC$ and $0.1 \ bar$ pressure. What is the molar mass of phosphorus (in $g/mol$)?

At what new pressure will $100 \ mL$ of a gas at a pressure of $720 \ mm$ occupy a volume of $84 \ mL$,keeping the temperature constant (in $mm$)?

State the combined gas law and the ideal gas equation.