The change in internal energy of a system depends upon

Which of the following expressions is true for an ideal gas?

Work done during isothermal expansion of $1 \, \text{mole}$ of an ideal gas from $10 \, \text{atm}$ to $1 \, \text{atm}$ at $300 \, \text{K}$ is ....... $\text{cal}$ (Gas constant $R = 2 \, \text{cal} \, \text{K}^{-1} \, \text{mol}^{-1}$) (in $.8$)

In the equation $C_P - C_V = R$,what does $R$ represent?

Consider the expansion given in problem $6.2$,for $1 \, mol$ of an ideal gas conducted reversibly.

$1.0 \ mol$ of a monoatomic ideal gas is expanded from state $(1)$ to state $(2)$ as shown in the figure. Calculate the work done for the expansion of the gas from state $(1)$ to state $(2)$ at $298 \ K$.