A piston filled with 0.04 mol of an ideal gas expands reversibly from 50.0 mL to 375 mL at a constan — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

For an isothermal process involving an ideal gas, the change in internal energy ($\Delta U$) is absolutely 0. According to the First Law of Thermodynamics, $\Delta U = q + w$. Thus, $0 = 208 \text{ J} + w$, giving $w = -208$ J. The negative sign correctly indicates work is done *by* the system.