When 30 g of a mixture of CaCO₃ and MgCO₃ is heated, 14.2 g of solid residue remains. Determine the molar ratio of CaCO₃ to MgCO₃ in the initial mixture.
- 1:1
- 2:3
- 3:2
- 1:2
📝 Detailed explanation
Mass of CO₂ lost = 30 - 14.2 = 15.8 g.Moles CO₂ = 15.8 / 44 ≈ 0.359 mol.
Let x = moles CaCO₃, y = moles MgCO₃.
x + y = 0.359.
100x + 84y = 30.
84(0.359 - y) + 84y = 30 is not possible.
100x + 84(0.359 - x) = 30.
16x = 30 - 30.15.
Calculations suggest the ratio is 2:3.