Experiment: Phase Change
The JAVA applet below simulates the dynamics of phase change in a liquid-vapor system.
Molecules of a pure substance in the vapor phase appear as green balls. The lime colored balls
represent the molecules of the same substance in the lquid phase. Select the relative magnitude
of the intermolecular forces of attraction in the liquid phase, enter the temperature in degrees Kelvin, and click the "start" button to
begin the animation. Click the "Stop" button to end the simulation. When the simulation stops, the average numbers of molecules in the vapor
and liquid phases are displayed above the reaction container.
- Select "weak" for the intermolecular forces, enter 200 K, and observe the animation for a couple
of minutes. Briefly characterize the vapor and liquid phases.
- Select "weak" for the intermolecular forces, enter 200 K, and observe the animation for a couple
of minutes. Briefly describe the process of phase change.
- Select "strong" for the intermolecular forces and observe the animation for 30 seconds at 200, 300, 400, and 500 K
. How and why does the average number of molecules in the vapor phase change with
a change in the temperature?
- Enter a temperature of 300 K and observe the animation for 30 second at each of the intermolecular
forces of attraction (weak, moderate, and strong). How and why does the average number of molecules in the
vapor phase change with a change in the magnitude of the intermolecular forces of attraction in the liquid
phase?
Include data from your experiments to support your answers to the questions.
Rodger Nutt; ronutt@davidson.edu
© Davidson College, September 1998