Chemistry 39

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Vapor Pressure and Boiling Point

The pressure of vapor present at equilibrium with its liquid is called the equilibrium vapor pressure – or, more commonly – the vapor pressure of the liquid. Vapor pressures of liquids vary widely. Liquids with high vapor pressures are called volatile – that is, they evaporate rapidly. Vapor pressure of a liquid at a given temperature is determined by the intermolecular forces acting among the molecules. There is a relationship between vapor pressure and boiling point of a liquid. This topic explores vapor pressure, and its relationship to boiling point.

Lesson 1 (or “Day 1”) Material
Lesson 2 (or “Day 2”) Material
Lesson 3 (or “Day 3”) Material
Lesson 4 (or “Day 4”) Material

insert videos here …

4:49 Vapor Pressure 101

5:34 Demonstration of Vapor Pressure

3:26 Vapor Pressure


Compare Contrast and Debate

Kickoff Debate Background: 
Vapor pressure is the pressure caused by the evaporation of liquids. Three common factors that influence vapor press are surface area, intermolecular forces and temperature. The vapor pressure of a molecule differs at different temperatures. (BrightStorm)

  • Position A: A variety of liquids and gases should be studied at ambient conditions before exploring temperature and pressure effects.
  • Position B: A single liquid or gas should be selected for examining at many temperature and pressure combinations prior to examining multiple liquids or gases.

Resources Documents and Links

Notes and Notices

Instructor Emphasis:

  • Science & Engineering Practice: Use mathematical and computational thinking.
  • Cross-Cutting Concept: Stability and Change.