1. Equilibrium Processes in Gases Slow (almost unchanging) with respect to the typical relaxation times of a system Equilibrium processes are represented by lines in the state space Processes in Ideal Gases Constant volume (isochoric) processes: No work done 1. law: Q V=const. 0 Equilibrium process: Quasi-static process which transforms the system through states of thermal equilibrium

2. Constant pressure (isobaric) processes P=const. 1. law: Q m P=const. Isothermal processes Work done @ T=const. T=const.

3. Adiabatic processes:No heat heat transfer in or out of the systemQ=0 How to realize an adiabatic process 1 2 very good insulation rapid changes in volume no time for heat to be exchanged 1. law: 0 Note: although the constant volume specific heat appears, expression applies to any process that starts and ends in equilibrium V0V0 In the limit V0V0 V0V0 First order differential equation or

4. Solution ofby integration with different from constant above

5. What is the work done in an adiabatic equilibrium process during entire adiabatic process Starting at P 0 and V 0

6. Graphic summary of various processes on a PV diagram: Constant volume (isochoric) process Constant pressure (isobaric) process Constant temperature (isothermal) process T high T low Isotherms for reference adiabatic process Q=0 Adiabat steeper than isotherm