Le Chatelier's Principle
The Chromate - Dichromate Equilibrium

In this lab you are trying to see (literally, since the effects you are looking for are visible color changes), how a system at equilibrium responds to change.


The use of chromium (VI) compounds is not allowed in many high schools, because of concerns about its carcinogenicity.   Because of the small amount used by students to carry out this lab, the risk to them is small; however, disposal of waste materials may pose a problem.  For this reason, teachers should be extremely cautious in having students carry out this procedure.   Consult your local school safety guidelines before doing so.

A set of photographs showing the various results are included for reference, so that you need not actually physically handle the chemicals.

Procedure (without photographs)

Procedure (with photographs)

Explanation of Results

Copyright 1998 - 2008 David Dice