Lab 5B: Composition of a Copper Sulfate Hydrate Lab

Lab 5A: Composition of a Copper Sulfate Hydrate Lab

Hydrate prior to heating it.

Hydrate after applying heat.

Calculations:

1. Mass of the hydrate used- mass of the evaporating dish (1.35g) subtracted from the mass of the evaporating dish and hydrate(2.25g) equaled to 0.900 grams.

2. Mass of the water lost- mass of evaporating dish and hydrate(2.25g) minus the mass of the evaporating dish and anhydrous salt(1.72g) equaled to 0.530 grams.

3. Percentage of water in the hydrate- divide mass of water lost (.530g) by the mass of hydrate used (.900g) to get 59%.

4. Percent error- |59-36|/36 *100 equals 38.9 percent error.

5. Moles of water evaporated was 2.94*10^-2. Moles of anhydrate that remained in the dish was 2.32*10^-5. Ratio of moles of CuSO4 to H2O was 13:1.

Empirical Formula: 1CuSO4 • 13H2O. The coefficient of the water molecule is not correct as indicated by the high percent error. Ours is much higher that it should be, and my estimate is that the real coefficient is around 5. We attribute the error to fluctuations on the scale while our team was measuring mass.