Crystallization from Solution, Demo #14

Using a supersaturated solution of sodium acetate in water, this demonstration illustrates three concepts:  the process of crystal growth from a solution, the properties of saturated solutions, and the idea that a seed crystal must be made of the same substance as the crystals that will grow.

Vapor Pressure of a Solution, Demo #16

This demonstration can be used to show that the vapor pressure of a homogeneous solution is the weighted average of the vapor pressures of the components (Raoult's Law).

Vapor Pressure of a Heterogeneous "Solution", Demo #17

In contrast to the vapor pressure behavior of homogeneous solutions, the equilibrium vapor pressure of a heterogeneous mixture (e.g., water and carbon tetrachloride( is the sum of the components vapor pressures.

Conductivity of Solutions, Demo #18

This demonstration uses a dimple conductivity tester made from a 9-volt battery and a flashlight bulb.  One can show strong and weak electrolytes.  An interesting part is showing that conductivity increases upon salt formation when a weak acid neutralized a weak base, e.g., ammonia and acetic acid.