Chem Class - April 14, 2010

Today we finished our test, and finished our conductivity lab by finding the conductivity of water. Distilled water on its own is not conductive, but as soon as we add salt (ions) the conductivity increases.

Electrical conduction in solutions requires charged ions to be present.
Ionic solutions dissociate (break apart) when placed in water. Molecular solutions do not usually split into ions
The following is the dissociation of sodium chloride:

Follow these steps to determine conductivity:
Is it a metal?
If yes it is conductive. If no ask...
Is it a solid non-metal?
If yes it is non-conductive. If no ask...
Is it an acid or base?
If yes it is conductive. If no ask...
Is it ionic?
If yes it is conductive. If no it is non-conductive.

Here is a video on electrical conductivity, demonstrating that ions must present in solution for electrical conductivity: