An ideal gas undergoes an isothermal expansion at 300 K. During this process, the gas does 500 J of work on the surroundings. What is the change in internal energy of the gas and the heat transferred to the gas?

Core Concept

For an ideal gas, the internal energy depends only on temperature. Since the process is isothermal (constant temperature), ΔU = 0 J. From the first law of thermodynamics, ΔU = Q - W, where Q is heat added to the system and W is work done by the system. Rearranging, Q = ΔU + W = 0 J + 500 J = 500 J.