phase changes

triple point

temperature and pressure where all three states of matter coexist

• all three equally stable and coexist in equilibrium

critical point

temperature and pressure at which the vapor pressure curve ends

supercritical fluid

liquid and gas are indistinguishable from each other

heating curve

1. solid begins to melt (first slope peak)

2. all solid melted (bottom of second slope)

3. liquid begins to boil (second slope peak)

4. all liquid evaporated (bottom of third slope)