i) How could you keep internal energy constant when you heat a gas inside a piston? ii) Which species will have a larger constant volume heat capacity, methane or benzene?

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50 GOA lab sample of gas is taken p through cycle abca shown in the p-V diagram of Fig. 18-43. The net work done is +1.2 J. Along path ab, the change in the internal energy is +3.0 J and the magnitude of the work done is 5.0 J. Along path ca, the energy trans- ferred to the gas as heat is +2.5 J. How much energy is transferred as heat along (a) path ab and (b) path bc? a b -V Figure 18-43 Problem 50.

27) Which of the following must be true for a thermodynamic process that starts and ends at the same state? A: The total heat and work for the cycle must both be zero B: The total work equals the heat C: The value of all state functions must be different at the beginning and the end of the process D: The change in internal energy over the whole cycle must equal 0 E: The temperature of the system will be constant throughout the process