Kinetic energy of particles, is proportional to how fast they vibrate Potential energy of atoms or molecules is proportional to the distance between the particles. Lower Potential E More Potential E Closer together Further apart

Line a: KE ↑ PE constant Point b: gained so much kinetic energy that the forces keeping the solid distances are overcome Line c: KE constant PE ↑ Between points b and d, molecules do not move faster, it will only cause the molecules to move further apart Line e: KE ↑ Point f: gained so much kinetic energy that the forces keeping the water at liquid distances are overcome. Line g: KE constant Along line g any energy added to the molecules will not cause the molecules to move faster, it will only cause the molecules to move further apart

Phase Diagrams

Critical temperature: temperature above which the vapor can not be liquefied.

Critical pressure: pressure required to liquefy AT the critical temperature.

Critical point: critical temperature and pressure (water = 374°C and 218 atm).

Phase changes by Name

Water

Carbon dioxide

Carbon

Sulfur