Name _________________________ Date _________________________ Period ___

Percent Composition of Epson Salt

Purpose: Determine quantitatively the (molar ratio) percent composition of Epson salts

(MaSO4 +    ?   H2O)

Procedure:

1. Mass Crucible
2. Fill less than ½ with Epsom Salts
3. Mass Crucible + hydrate
4. Light burner
5. Heat hydrate
6. Turn off burner
7. Cool for 5 min
8. Mass Crucible + MgSO4
9. Input data into computer and print results
10. Complete the following calculation in the space provided.

Data:

1. Mass of crucible ______
2. Mass of crucible + hydrate ________
3. Mass of hydrate ______

1. Mass of anhydrous salt ______

Calculation

1. Mass of water ________

Mg = 24.3 g/mol H = 1.0 g/mol O = 16.0 g/mol S = 32.1 g/mol     Calculation

1. Percent composition by mass ________

Calculation

1. Percent composition by formula ______

Calculation

Conclusions:

Why is it necessary to let the crucible cool before massing it? 5%

Why should the mass of the crucible be measured immediately after it cools and not later? 5%

 Find result from at least two other groups. (% comps)

Compare your results with the results of other members of you class. Are there differences? If so give reasons for the differences. 10%