Calculate how many grams of 10% solutions of the starting salts will be required to obtain 75 g of calcium carbonate.

Since the initial salts are not indicated in the problem statement, we take sodium carbonate and calcium nitrate – soluble salts. Let us write the equation for the reaction of the interaction of salts, in which calcium carbonate is formed.

Na2CO3 + Ca (NO3) 2 = CaCO3 + 2NaNO3

Let us find the number of moles of calcium carbonate, knowing its mass.

n (CaCO3) = m / M = 75/100 = 0.75 mol

According to the reaction equation n (CaCO3) = n (Na2CO3) = n (Ca (NO3) 2) = 0.75 mol.

Let’s calculate the mass of salts.

m (Ca (NO3) 2) = n * M = 0.75 * 164 = 123 g

m (Na2CO3) = n * M = 0.75 * 106 = 79.5 g

Next, we find the mass of 10% solutions of these salts.

m (Ca (NO3) 2 (solution)) = 123 * 100/10 = 1230 g

m (Na2CO3 (solution)) = 79.5 * 100/10 = 795 g