The effect of temperature on the position of an equilibrium can easily be seen in this demonstration by observing the colour changes of the octahedral hexaaquocobalt(II) cation and the tetrahedral tetrachlorocobaltate(II) anion as the sample is moved from a low temperature to a high temperature.
You can set it up so that two halves of the tube are at different temperatures and thus of different colours.
Cobalt compounds are carcinogenic but the risk is not great in this experiment. However, anyone concerned about the safety of using tem can use the alternative that uses copper chloride. The colour change is not quite as dramatic but it is clear to see.
