Solid Copper (II) Nitrate Synthesis Lab Report

http://www.chem-toddler.com/chemical-equilibrium/chromatedichromate.html http://ibchem.com/IB/ibnotes/full/aab_htm/18.3.htm In the experiment part (i) (a), the solid copper(II) nitrate is used to dissolve in a test tube filled with half distilled water. The solid copper(II) nitrate ionize in water to form copper(II) ions and nitrate ion. Hence, a blue solution is formed due to the blue copper(II) ion present in the solution. When excess solid is added, the solution will become saturated and do not allow any solid to dissolve, so excess solid will remain in the solution. This is shows that the equilibrium between solid and aqueous copper(II) nitrate is achieved. When the test tube is being placed in the water bath of 60 , the level of
The cobalt (II) chloride is added with hydrochloric acid, which a pink solution is formed. When the test tube is placed in a water bath with 60 , the solution turns from light pink to dark pink. This is because the cobalt(II) chloride dissolve in solution is an endothermic reaction which it tend s to form blue cobalt (II) chloride in the solution. The dark pink solution is formed instead of light pink because the dark pink colour of solution is the mixture of pink and blue. The equilibrium position shift to right in the equilibrium equation below:
[Co[H2O]6]2+ (aq) + 4Cl-(aq) [CoCl4]2- (aq) + 6H2O (l)
Since the equilibrium equation above is an endothermic reaction, the position of equilibrium tends to shift to right at high temperature, 60 in this experiment. The increase in equilibrium constant leads to more products is formed. So, the colour changes to dark pink due to the amount of cobalt(II) chloride formed is increases. On the other hand, the equilibrium position shifts to the left at the temperature of 0 . When the equilibrium shifts to left, the concentration of hydrated cobalt ion form and hence the solution forms at a light pink