Phase Changes/Heating Cooling Curves

Blog Post #2

(April 26, 2016)

Our last lecture of this unit presented us with two different types of graphs:

Heating and Cooling Curve: Shows where an element/compound will freeze/boil/melt.

Add caption

http://www.kentchemistry.com/images/links/matter/HeatCool.gif


Things to Know about Heating/Cooling:

• change of state is a physical change    
• melting and boiling points are determined by the vapor pressures of the solid and liquid states
• at 0 degrees Celsius, ice and liquid water have the same vapor pressure.
• at 100 degrees Celsius, water vapor and atm are equal.

Phase Diagram: A representation of the states of a substance in relation to temperature and pressure.

http://d2vlcm61l7u1fs.cloudfront.net/media%2F654%2F654abc63-5ebf-4f33-9507-c38acd719f38%2FphpAsNMSr.png

Things to Know about Phase Diagrams:

• triple point-point at which the solid, liquid, and vapor states all have the same vapor pressure and coexist.
• critical temperature-the temperature above which the vapor cannot be liquefied, regardless of the pressure applied.
• critical pressure-the pressure required to liquefy the vapor at the critical temperature
• critical point-point at which the critical temperature and critical pressure coincide

Useful Links:

Heating and Cooling Curves

Heating Curves

Crash Course-Enthalpy