When dissolving the CaCl2 * 6H2O crystalline hydrate weighing 219 g in 1000 g

When dissolving the CaCl2 * 6H2O crystalline hydrate weighing 219 g in 1000 g of water, a solution is formed with a mass fraction (%) of calcium chloride?

Given:
m (CaCl2 * 6H2O) = 219 g
m (H2O) = 1000 g

To find:
ω (CaCl2) -?

Decision:
1) Find the amount of substance CaCl2 * 6H2O:
n (CaCl2 * 6H2O) = m (CaCl2 * 6H2O) / Mr (CaCl2 * 6H2O) = 219/219 = 1 mol;

2) Find the amount of substance CaCl2 (by definition of the amount of substance):
n (CaCl2) = n (CaCl2 * 6H2O) = 1 mol;

3) Find the mass of the substance CaCl2:
m (CaCl2) = n (CaCl2) * Mr (CaCl2) = 1 * 111 = 111 g;

4) Find the mass of the resulting CaCl2 solution:
m solution (CaCl2) = m (CaCl2 * 6H2O) + m (H2O) = 219 + 1000 = 1219 g;

7) Find the mass fraction of CaCl2 in the solution:
ω (CaCl2) = m (CaCl2) * 100% / m solution (CaCl2) = 111 * 100% / 1219 = 9.1%.

Answer: The mass fraction of CaCl2 in the solution was 9.1%.