Epsom salts consist of magnesium sulfate heptahydrate. Write its formula.

a) How many atoms of oxygen are in 5.15g of Epsom salts?
b) How many formula units of the compound are present in 5.15g?
c) How many moles of water molecules are in 5.15 g of Epsom salts?

Thank you so much!!

2 answers

MgSO4.7H2O

b) 5.15/formula mass = ?
a) moles O atoms = formula units of MgSO4.7H2O x {[4(for 1SO4)+7(for 7H2O)]*6.022E23}= answer from a x 11 x 6.022E23 = ?
c) formula units from a x 7
Taymis