9. A hydrate is a compound that has water molecules within its crystal structure. Magnesium sulfate septahydrate, MgSO4 · 7H2O, is a hydrated form of magnesium sulfate. The hydrated compound has 7 moles of H2O for each mole of MgSO4. When 12.36 g of MgSO4 · 7H2O are heated to at least 300°C in a crucible by using a laboratory burner, the water molecules evaporate. The sample was heated repeatedly, until all of the water molecules evaporated and the remaining MgSO4 had a constant mass of
6.24 g.
a) Calculate the mass of water evaporated
b) Calculate the gram formula mass of MgSO4 · 7H2O
c) Calculate the percent composition by mass of water in the hydrated compound, MgSO4 · 7H2O

Please I need it as soon as possible and can you please show how you did it thanks much appreiciated