Bath salts such as epsom contain hydrate salts such as mgso 4 ·7h 2 o (magnesium sulfate heptahydrate). when heated, water is released as vapor and anhydrous mgso 4 remains. determine how many moles of vapor are released when 15.5 g of mgso 4 ·7h 2 o are heated. hint: include h 2 o when calculating the molar mass.

0.369 moles of H₂O.

Explanation:

The molar mass of the hydrate salt is equal to the molar mass of the anhydrous salt plus the molar mass of water times the moles of water.

M(MgSO₄·7H₂O) = M(MgSO₄) + 7 × M(H₂O)

M(MgSO₄·7H₂O) = 168 g/mol + 7 × 18 g/mol

M(MgSO₄·7H₂O) = 294 g/mol

Every 294 g of MgSO₄·7H₂O there are 126 g of H₂O. So, for 15.5 g of MgSO₄·7H₂O,