Answer to Question #110613 in Physical Chemistry for DEEPAK SINGH

Question

Draw and explain the steps involved in carnot cycle.

Answer 1

The Carnot cycle consists of the following four processes:

1. A reversible isothermal gas expansion process. In this process, the ideal gas in the system absorbs q_in amount heat from a heat source at a high temperature T_high, expands and does work on surroundings.
2. A reversible adiabatic gas expansion process. In this process, the system is thermally insulated. The gas continues to expand and do work on surroundings, which causes the system to cool to a lower temperature, T_low.
3. A reversible isothermal gas compression process. In this process, surroundings do work to the gas at T_low, and causes a loss of heat, q_out.
4. A reversible adiabatic gas compression process. In this process, the system is thermally insulated. Surroundings continue to do work to the gas, which causes the temperature to rise back to T_high.

The P-V diagram of the Carnot cycle:

In isothermal processes I and III, ∆U=0 because ∆T=0. In adiabatic processes II and IV, q=0.