Question

Guys I need your help!! It’s due tomorrow! I would be very grateful if you could help me!

A hydrate has the formula of MgSO4 * 7H₂O. What is the percent water in this hydrate?

Answer 1

51.16% H₂O

Step-by-step explanation:

To find the percent water in the hydrate, you need to

(1) calculate the masses of 7H₂O and MgSO₄ · 7H₂O

(2) calculate the percent composition

(Step 1)

Atomic Mass (Mg): 24.305 g/mol

Atomic Mass (S): 32.065 g/mol

Atomic Mass (O): 15.999 g/mol

Atomic Mass (H): 1.008 g/mol

Mass (MgSO₄): 24.305 g + 32.065 g + 4(15.999 g/mol) = 120.366 g

Mass (7H₂O): 14(1.008 g/mol) + 7(15.999 g/mol) = 126.105 g

Mass (MgSO₄·7H₂O): 120.366 g + 126.105 g = 246.471 g

(Step 2)

Mass Water
Percent Composition = ---------------------------- x 100%
Total Mass

126.105 g H₂O
Percent Composition = -------------------------------------- x 100%
246.471 g MgSO₄·7H₂O

Percent Composition = 51.16% H₂O