The mass of calcium sulfate obtained by the interaction of 7.4 g of calcium hydroxide and 4.9 g of sulfuric acid is …

Given:
m (Ca (OH) 2) = 7.4 g
m (H2SO4) = 4.9 g

To find:
m (CaSO4) -?

Decision:
1) Ca (OH) 2 + H2SO4 => CaSO4 + 2H2O;
2) n (Ca (OH) 2) = m (Ca (OH) 2) / M (Ca (OH) 2) = 7.4 / 74 = 0.1 mol;
3) n (H2SO4) = m (H2SO4) / M (H2SO4) = 4.9 / 98 = 0.05 mol;
4) n (CaSO4) = n (H2SO4) = 0.05 mol;
5) m (CaSO4) = n (CaSO4) * M (CaSO4) = 0.05 * 136 = 6.8 g.