Question

Write the balanced reaction equation for the precipitation of calcium carbonate from
potassium carbonate and calcium chloride. Don't forget to show the states of matter.

Answer 1

The balanced equation when potassium carbonate reacts with calcium chloride to form calcium carbonate is :

                   K₂CO₃(aq) + CaCl₂(aq) CaCO₃ (s) + 2KCl(aq)

Determination of limiting reactant:

Molar mass of K₂CO₃ is = sum of the individual atomic masses

                                   = (2x39)+(1x12)+(3x16)

                                   = 138 g/mol

Molar mass of CaCl₂ is = sum of the individual atomic masses

                                   = (1x40)+(2x35.5)

                                   = 111 g/mol

Accorging to the balanced equation ,

1 mole of K₂CO₃ reacts with 1 moles of CaCl₂

                            OR

138 g of K₂CO₃ reacts with 111 g of CaCl₂

25 g of K₂CO₃ reacts with Z g of CaCl₂

So 25-20.1 = 4.9 g of CaCl₂ left unreacted, which is the excess reactant.

All the K₂CO₃ completly reacted K₂CO₃ is the limiting reactant.