Rust has the formula Fe₂O₃ and it's made from iron metal reacting with oxygen over time. Assume you have a 33.5 g block of pure iron metal that is fully oxidized to rust and the mass of the rust product produced is 22.12 g. What must have been the mass of oxygen that initially reacted with pure iron?
Unbalanced chemical equation is: ___ Fe(s) + ____ O₂ → ___ Fe₂O₃
A. 3.32 g
B. 0.208 g
C. 6.65 g
D. 1.16 g