Question

A chemist heats 100.0 g of FeSO4 x 7H2O in a crucible to drive off the water. If all the water is driven off, what is the mass of the remaining salt?

Answer 1

FeSO₄*7H₂O(s) = FeSO₄(s) + 7H₂O(g)

M(FeSO₄*7H₂O)=278.0 g/mol
M(FeSO₄)=151.9 g/mol

m(FeSO₄*7H₂O)/M(FeSO₄*7H₂O)=m(FeSO₄)/M(FeSO₄)

m(FeSO₄)=M(FeSO₄)m(FeSO₄*7H₂O)/M(FeSO₄*7H₂O)

m(FeSO₄)=151.9*100.0/278.0=54.6 g

m(FeSO₄)=54.6 g

Answer 2

The correct answer is 54.6g