If $2$ moles of an ideal gas at $546 \ K$ has a volume of $44.8 \ L$,then what will be its pressure (in $atm$)? $(R=0.082 \ L \ atm \ K^{-1} \ mol^{-1})$

Which of the following is equal to $[{\partial P/\partial V}]_T$ for an ideal gas?

$A$ 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.)

In the equation $PV = nRT$,the number of moles per liter can be expressed as:

$A$ and $B$ are ideal gases. At $T(K)$,$2 \ L$ of $A$ with a pressure of $1 \ bar$ is mixed with $4 \ L$ of $B$ with a pressure $p_B \ bar$ in a $100 \ L$ flask. The pressure exerted by the gaseous mixture is $0.1 \ bar$. What is the value of $p_B$ in $bar$?

What is the number of molecules in $0.082 \ L$ of an ideal gas kept at a temperature of $400 \ K$ and a pressure of $10 \ atm$?