A diatomic gas of volume 6 litres at 300 K and 1 atm is compressed adiabatically to half its volume, then cooled at constant pressure to 300 K (a compression), and finally expanded isothermally to its

Question

A diatomic gas of volume 6 litres at 300 K and 1 atm is compressed adiabatically to half its volume, then cooled at constant pressure to 300 K (a compression), and finally expanded isothermally to its initial state. Find the net work done by the gas in the cycle in joules (nearest integer, negative if work is done on the gas).

TestHub · Accepted Answer

T 2 ​ = 300 × 2 0.4 = 395.9 K and P 2 ​ = 2 1.4 atm. n = RT P V ​ = 0.2437 mol. W 1 ​ = − n C v ​ Δ T = − 485 J. Isobaric: V 3 ​ = 3 × 395.9 300 ​ = 2.27 litre, W 2 ​ = P 2 ​ Δ V = − 194 J. Isothermal from 2.27 to 6 litre: W 3 ​ = n RT ln 2.27 6 ​ = 590 J. Net = − 90 J.

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