Understand the first law (ΔU = Q − W): at constant volume all added heat becomes internal energy, but at constant pressure some heat leaves as boundary work.
Heat, Q
0 JWork, W
0 JΔU
0 JTemperature
300 KΔU = Q − WConstant volume: W = 0, ΔT = Q / (n·Cv)Constant pressure: W = n·R·ΔT, ΔT = Q / (n·Cp)Stay in Constant Volume mode. Add 2000 J of heat and confirm that ΔU equals Q exactly, because no boundary work is done.
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