posted by Jo .
Why does the equation Co(H2O)6 + 4Cl <------> CoCl4 + 6H2O shift left when cooled?
[Co(H2O)6]^2+ + 4Cl^- + heat ==> (CoCl4)^2-^
Le Chatelier's Principle tells us that a system in equilibrium will shift so as to undo what we do to it. If we add heat the reaction above will shift to the right in order to use up the heat we've added. If we cool the system it will shift to the left in order to add heat back to the system.