An ideal gas undergoes an isothermal expansion. Which of the following correctly describes what happens to the internal energy and the temperature of the gas?

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Question

An ideal gas undergoes an isothermal expansion. Which of the following correctly describes what happens to the internal energy and the temperature of the gas?

Accepted Answer

A. Internal energy unchanged; temperature unchanged — In an isothermal process, temperature remains constant by definition. Since the internal energy of an ideal gas depends only on temperature (no intermolecular potential energy), the internal energy also remains unchanged during isothermal expansion.

Answer

D. Internal energy decreases; temperature decreases

Answer

C. Internal energy unchanged; temperature decreases

Answer

A. Internal energy unchanged; temperature unchanged

Answer

B. Internal energy increases; temperature unchanged

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