A mixture of 1 mol He and 1 mol H 2 (ideal, vibrations not excited) at pressure P and volume V is isothermally compressed to V/16, giving pressure P i . Starting from the same initial state it is inst

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A mixture of 1 mol He and 1 mol H 2 (ideal, vibrations not excited) at pressure P and volume V is isothermally compressed to V/16, giving pressure P i . Starting from the same initial state it is instead compressed reversibly and adiabatically to V/16, giving pressure P a . The ratio P a /P i is

TestHub · Accepted Answer

For the mixture C v = 3/2R + 5/2R = 4R and C p = 6R (per 2 mol), so γ mix = 1.5. Isothermal: P i = 16P. Adiabatic: P a = 16 1.5 P = 64P. P a /P i = 16 0.5 = 4. (Averaging the two γ values gives 4.4, which is wrong.) Matches (c).

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