Lab 5B: Mole-Mass Relationship Lab

Data

Mass of evaporating dish- 1.32 g

Mass of evaporating dish + Hydrate- 2.16 g

Mass of evaporating dish + anhydrous salt- 1.96 g (1st heating)

                                                                      1.84 g (2nd heating)

                                                                      1.79 g (3rd heating)

Calculations

1. 2.16g - 1.32g = 0.84g (mass of hydrate used)

2. 1.79g - 1.32g = 0.47g

    0.84g - 0.47g = 0.37g (mass of water lost)

3. (0.37g/0.84g) * 100 = 44% (percentage of water in the hydrate)

4. Percent Error = |44-36|/36 x 100

    Percent Error = 22% error

5. CuSO₄* 7H₂O

Since our percent error was very high(22%), the empirical formula above is not correct. Since the percentage of water in the hydrate was higher than the accepted value(36%), the ratio would most likely be lower than 7.

Hydrate prior to heating

Hydrate after heating