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

💡 Solution & Explanation

Because the process is maintained at a constant temperature, it is an isothermal process. For an ideal gas, $\Delta U = 0$ J continuously. By the First Law, $\Delta U = q + w$. Thus, all 208 J of absorbed heat is exhausted as expansion work: $0 = 208 + w \Rightarrow w = -208$ J.