Follow up Questions

9. The evidence that we obtained to indicate that a reaction occurred between Cu2+ ions and water was when the water was added the Cu2+ it had turned back to its turquoise blue color. Also, when the water had been added to the Cu+2 ions, the product in the test tube heated up.

10. The chemical system possess more energy after we added water to the anhydrous copper(II) sulfate. After heating the hydrated copper(II) sulfate, there was energy still in from heating it with the bunsen burner. When putting the anhydrous copper(II) sulfate then in the test tube and then adding water, it is then shown that there was a more energy because copper(II) sulfate temperature began to increase. To account for the observed energy change, we placed a thermometer in the test tube and began to add the water which increased to 40o.

11. The evidence that we have to that NH3 reacted with Cu(H2O)42+ was that the color changed from a turquoise blue to a dark blue on the top part of the water.

12. Evidence that the concentration of Cu(NH3)42+ changed when sulfuric acid was added was that both blues had started to lose there colors and turned clear.

table

1 Mass of crucible and hydrated barium chloride 14.93g

2 Mass of crucible 11.93g

3 Mass of hydrated barium chloride 3.00g

4 Mass of crucible and anhydrous barium chloride 14.45g

5 Mass of crucible 11.93g

6 Mass of anhydrous barium chloride 2.52g

Data Table II Formation and Reaction of a Hydrate

Procedure Change in Observation

Heat CuSO4 * 5H2O Color Light blue turned to greenish gray

Add H2O to CuSO4 Color-

Energy- Turquoise blue

40o then dropped

Add NH3 to CuSO4 * 5H2O Color Dark blue

Add H2SO4 to Cu(NH3)42+ Color Clear