Temperature Dependence of Emf

In this experiment you will study the temperature dependence of the electrochemical cell

                                                    Cd (s) | Cd ²⁺ SO₄ ^2- (aq, c) | Cd (Hg, X₂) 1 bar, T                                                            for which the net reaction is:             

                                                                Cd (s) <===> Cd (Hg, X₂) 1 bar, T

This temperature dependence will allow you to determine DG, DS, DH, and DG^o for the net reaction.  This experiment is taken from Experiments in Physical Chemistry, Shoemaker, D. P., Garland, C. W. and Nibler, J. W., 5^th ed., McGraw-Hill Book Company, San Francisco (1989).  This experiment which contains the theoretical background, materials and chemicals, experimental procedure, data, calculations, and references is reproduced in the MS Word document Temperature Dependence of Emf.

This experiment involves some elementary glass blowing.  Tuturials and hints on how to blow glass can be found at East Carolina University's Glass Blowing Services web site.

Safety

The reagents used in this lab, Cd (s), Cd²⁺ (aq), CsSO₄ (s), Hg (l), and Cd(Hg) amalgam are all toxic and should be handled with care, being careful not to leave residue from these materials on your skin, to ingest these materials, or to breath their vapors.   Hg also readily amalgamates with Au and so you should remove all gold jewelry before attempting this experiment.  All of these materials should be properly disposed of at the end of the experiment.

When constructing the glass electrodes, be aware that hot glass does not appear hot and it is very easy to burn yourself - be careful!