Use the worked example above to help you solve this problem. A balloon contains $5\mathrm{.}20$ moles of a monatomic ideal gas. As energy is added to the system by heat $($say$,$ by absorption from the Sun$),$ the volume increases by $25\%$ at a constant temperature of $21\mathrm{.}0$C$.$

Find the work Wenv done by the gas in expanding the balloon, the thermal energy Q transferred to the gas, and the work W done on the gas.