How does a thermal power plant work?

$10$ moles of an ideal gas confined to a volume of $10 \, L$ is released into the atmosphere at $300 \, K$ where the pressure is $1 \, bar$. The work done by the gas is ....$L \, bar$
$(R = 0.083 \, L \, bar \, K^{-1} \, mol^{-1})$

Identify the state functions and path functions out of the following: enthalpy,entropy,heat,temperature,work,free energy.

$A$ perfect gas $(0.1 \ mol)$ having $\overline{C}_{v}=1.50 \ R$ (independent of temperature) undergoes the transformation shown in the graph from point $1$ to point $4$. If each step is reversible,the total work done $(w)$ while going from point $1$ to point $4$ is $(-)$ . . . . . . $J$ (nearest integer). [Given: $R=0.082 \ L \ atm \ K^{-1} \ mol^{-1}$,$1 \ L \ atm = 101.3 \ J$]

For $1 \text{ mole}$ of an ideal gas expanding isothermally from $1 \text{ L}$ to $10 \text{ L}$ at $300 \text{ K}$,the value of $\Delta U$ is: $(R = 2 \text{ cal mol}^{-1} \text{ K}^{-1})$

For a massless piston undergoing an expansion of $\Delta V$ at constant temperature against a variable external pressure $P$,which equation represents the work done?