Sodium sulfate weighing 7.1 g. dissolved in water, an excess of barium chloride solution was added

Sodium sulfate weighing 7.1 g. dissolved in water, an excess of barium chloride solution was added to the resulting solution. The precipitate was filtered. Write down the molecular and ionic equations of the ongoing reaction. Determine the mass of the resulting sediment.

Given:
m (Na2SO4) = 7.1 g

To find:
m (draft) -?

Decision:
1) Na2SO4 + BaCl2 => BaSO4 ↓ + 2NaCl;
2Na + + SO42- + Ba2 + + 2Cl- => BaSO4 ↓ + 2Na + + 2Cl-;
SO42 – + Ba2 + => BaSO4 ↓;
2) M (Na2SO4) = Mr (Na2SO4) = Ar (Na) * N (Na) + Ar (S) * N (S) + Ar (O) * N (O) = 23 * 2 + 32 * 1 + 16 * 4 = 142 g / mol;
M (BaSO4) = Mr (BaSO4) = Ar (Ba) * N (Ba) + Ar (S) * N (S) + Ar (O) * N (O) = 137 * 1 + 32 * 1 + 16 * 4 = 233 g / mol;
3) n (Na2SO4) = m (Na2SO4) / M (Na2SO4) = 7.1 / 142 = 0.05 mol;
4) n (BaSO4) = n (Na2SO4) = 0.05 mol;
5) m (BaSO4) = n (BaSO4) * M (BaSO4) = 0.05 * 233 = 11.65 g.

Answer: The mass of BaSO4 is 11.65 g.