Question

A sample of dolomite contained 45% of CaCO3,40% of MgCO3 and 15% clay. Calculate the mass of sulphuric acid of 30% strength required to react completely with 10 g of the sample.

Answer 1

Supposing clay doesn't react with H2SO4.

Supposing the given percentages are by mass:

CaCO3 + H2SO4 → CaSO4 + H2O + CO2

(45% of 10 g) / (100.0875 g CaCO3/mol) x (1 mol H2SO4 / 1 mol CaCO3) =

0.04496 mol H2SO4 to react with the CaCO3

MgCO3 + H2SO4 → MgSO4 + H2O + CO2

(40% of 10 g) / (84.31413 g MgCO3/mol) x (1 mol H2SO4 / 1 mol MgCO3) =

0.04744 mol H2SO4 to react with the MgCO3

(0.04496 mol + 0.04744 mol) x (98.0791 g H2SO4/mol) / (0.30) = 30 g 30% H2SO4