Lab 9: Composition of a Copper Sulfate Hydrate Lab

Data: In moles, the amount of water that evaporated was 0.017 moles. We got this by dividing the grams of water evaporated by the molar mass of water. Similarly, the moles of Copper Sulfate, the anhydrate, that was left in the evaporating dish was the grams of Copper Sulfate left divided by the molar mass of Copper Sulfate, or 0.0035 moles. To find the empirical formula, we needed the ratio of moles of CuSO₄ to H₂O. We did this by dividing by the smallest amount, which was the moles of CuSO₄. We got a ratio of 5 water to 1 Copper Sulfate. As such, the empirical formula was CuSO₄ * 5H₂O. Our percentage of water was 36.9%, less than a tenth of a percent away from the accepted value for the percentage of water. Our percent error was, as such, 2.85%. This means our coefficient is very close to the actual. It is probably a little high, as our experimental value was as well.

Hydrates before and after heating (from left to right):

 Calculations: