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.

Using this balanced equation in the above question, determine the limiting reactant if 25 grams of calcium chloride
reacted with 25 grams of potassium carbonate. Show your work.

Answer 1

balanced reaction:

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

solution:

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

138g                 111g

25g                     25g

138 g K2CO3 react with ----------------> 111g CaCl2

25 g K2CO3 react with ----------------> x g CaCl2

x = 25 x 111 / 138

x = 20.11 g

actually for 25 g K2CO3 we need only 20.11 g CaCl2 . but here we have excess substance 25g CaCl2 . so it is not limiting reagent

next :

138 g K2CO3 react with ----------------> 111g CaCl2

y g K2CO3 react with ----------------> 25 g CaCl2

y = 25 x 138 /111

y = 31 .08

for 25 g CaCl2 we need 31.08 g K2CO3 needed . but we have only 25 g . so it is limiting reagent.

K2CO3 is limiting reagent