What is the mass of sulfur, which has reacted with 16 g of oxygen, if sulfur oxide SO2 is formed?

Given:
m (O2) = 16 g

To find:
m (S) -?

Decision:
1) Write the reaction equation:
S + O2 => SO2;
2) Calculate the amount of substance O2:
n (O2) = m (O2) / M (O2) = 16/32 = 0.5 mol;
3) Determine the amount of substance S:
n (S) = n (O2) = 0.5 mol;
4) Calculate the mass S:
m (S) = n (S) * M (S) = 0.5 * 32 = 16 g.

Answer: The mass of S is 16 g.