Figure 13-2 illustrates a spontaneous process through the expansion of an ideal gas into an evacuated bulb.

Question:

Figure 13-2 illustrates a spontaneous process through the expansion of an ideal gas into an evacuated bulb. Use the one-dimensional particle-in-a-box model to represent the initial condition of Figure 13-2. Use a second particle-in-a-box model to represent the system after expansion into the vacuum. Use these models to explain on a microscopic basis why this expansion is spontaneous.

Figure 13-2

n (a) Initial condition HO (b) After expansion into vacuum