A sample weighing 89760 g of magnesium sulfate hydrate was h

A sample weighing 8.9760 g of magnesium sulfate hydrate was heated to drive off the water in the sample. After heating the sample weighed 4.3840 g

a) How many moles of water were in the sample

b) if the amount of magnesium in the sample was detremined to be 0.8851 g, how many moles of magnesium were in the sample?

c)How many moles of sulfate were in the sample

d) what is the empirical formula of the hydrate

a) weight of water = 8.976-4.3840= 4.592g

Moles of water in sample = 4.592/18 = 0.2551

b) Molecular weight of Megnesium of 24 and given weight = 0.8851

Moles = 0.8851/24 = 0.0368

c) Weight of sulfate of = 8.976-4.3840-0.8851 = 3.7069gm

Mole of sulfate = 3.7069/96= 4.58

d) Assume Molecular formula = MgSO4.nH2O

moles of H2O in this formula = 18n/18 = n

By given value the moles of H2O = 0.25 in 4.3840/120 = 0.036mole of MgSO4

In 0.036mole of MgSO4 mole of H2O = 0.25

In 1mole of MgSO4 mole of H2O = 0.25/0.036= 6.94 ~7 = n

So empirical formula of the hydrate = MgSO4.7H2O