What mass of sulfur (IV) oxide is formed by the interaction of 20 g of sulfur with oxygen.

Given:
m (S) = 20 g

To find:
m (SO2) -?

1) S + O2 => SO2;
2) M (S) = Ar (S) = 32 g / mol;
3) n (S) = m / M = 20/32 = 0.6 mol;
4) n (SO2) = n (S) = 0.6 mol;
5) M (SO2) = Mr (SO2) = Ar (S) * N (S) + Ar (O) * N (O) = 32 * 1 + 16 * 2 = 64 g / mol;
6) m (SO2) = n * M = 0.6 * 64 = 38 g.

Answer: The mass of SO2 is 38 g.