An ideal monoatomic gas initially at 300 K expands adiabatically into vacuum to double its volume. T — Thermodynamics and Thermochemistry Chemistry Question

💡 Solution & Explanation

Adiabatic expansion into vacuum is free expansion (P_ext = 0). Thus, w = 0. Since it is also adiabatic, q = 0. By First Law, Δ U = q + w = 0. For an ideal gas, since Δ U = 0, temperature must remain constant. So the final temperature is 300 K.