Task 74g of a solution containing 30% calcium chloride was mixed with sodium carbonate solution.

Task 74g of a solution containing 30% calcium chloride was mixed with sodium carbonate solution. Determine the mass of the sediment formed.

Given:
m solution (CaCl2) = 74 g
ω (CaCl2) = 30%
Find: m (draft) -?
1) CaCl2 + Na2CO3 => CaCO3 ↓ + 2NaCl;
2) m (CaCl2) = ω * m solution / 100% = 30% * 74/100% = 22.2 g;
3) M (CaCl2) = Mr (CaCl2) = Ar (Ca) * N (Ca) + Ar (Cl) * N (Cl) = 40 * 1 + 35.5 * 2 = 111 g / mol;
4) n (CaCl2) = m / M = 22.2 / 111 = 0.2 mol;
5) n (CaCO3) = n (CaCl2) = 0.2 mol;
6) M (CaCO3) = Mr (CaCO3) = Ar (Ca) * N (Ca) + Ar (C) * N (C) + Ar (O) * N (O) = 40 * 1 + 12 * 1 + 16 * 3 = 100 g / mol;
7) m (CaCO3) = n * M = 0.2 * 100 = 20 g.
Answer: The mass of CaCO3 is 20 g.