Answer to Question #152378 in General Chemistry for O.Weerasinghe

Question

In a water solubility test of aqueous magnesium sulphate at room temperature, more than 25cm3 of baCl2 [aq] was added to its saturated solution. What is the maximum mass of aqueous MgSO4 dissolved in 100g of water at room temperature?Explain with steps, [The density of saturated MgSO4 (aq) is 1.21gcm-3.]

Answer 1

Mass of MgSO4 at saturated solution = density*volume = 100ml*1.21gcm-3 = 121 g

MgSO4 + BaCl2 = MgCl2 + BaSO4

n(MgSO4) = 121g/120g/mol = 1 mol

n(BaCl2) = 25g/208g/mol = 0.12 mol

According to the equation 0.12 mol of MgSO4 reacts with BaCl2, then

m(MgSO4) = 0.88mol*120g/mol = 105.6 g will be dissolved in 100g of solution at room temperature