Investigation of Systems at Equilibrium

Preparation
Procedure

Index

The Hexaaquocobalt (II) - Tetrachlorocobalt(II) System Revisited

You will again be examining the hexaaquocobalt (II) - tetrachlorocobalt(II) equilibrium described by the following expression:

Place test tube B in an ice bath, created by filling a 600 mL beaker with tap water and ice (the ice will be provided by your TA).

Allow five to ten minutes to pass while the test tube cools in the ice bath. During this time, use Le Chatlier's principle to predict what color changes will occur. Note the color change observed after this time in your laboratory notebook.

 

Place test tube B in a 250mL beaker that is half-filled with tap water. Place the beaker over a Bunsen burner atop a wire gauze square and iron ring. Light the Bunsen burner and heat the water bath until the water is hot but not boiling. After five to ten minutes, note the change in solution color.

heat hot water

In your laboratory notebook, note how the equilibrium shifted with the addition of heat.

 

Turn off the Bunsen burner and allow the water bath to cool. Once it is nearly room temperature and can be taken off the wire gauze by hand, dispose of the contents of test tube B in the appropriate waste carboy. Clean and dry the test tube and all of the other unwashed glassware before leaving the laboratory.

 

Once you have cleaned up your station and replaced all of your equipment in the proper place, you're finished! You've learned how LeChatlier's principle can be used to predict how an equilibrium system will change with the addition or removal of chemicals or heat.