Question

Suppose 1.1854g of copper(II) sulfate pentahydrate is heated to drive off the water of crystallization. Calculate what mass of water would be expected to be released from the salt.

Answer 1

1) Copper(II) sulfate pentahydrate formula

CuSO4.5H2O

2) Molar mass, MM

63.55g/mol + 32.07g/mol +4*16g/mol + 5*18g/mol = 249.62 g/mol

3) Proportion of water in the molecule of CuSO4.5H2O

18.0 g H2O / 249.62 g CuSO4.5H2O

4) Water in 1.1854 g of CuSO4.5H2O

1.1854 gCuSO4.5H2O * [18.0 gH2O / 249.62 gCuSO4.5H2O] = 0.08548 gH2O

Answer: 0.08548 g