Sulfur and Oxygen React in a Combination Reaction to Produce

Multiple Choice

Sulfur and oxygen react in a combination reaction to produce sulfur trioxide, an environmental pollutant: 2S (s) + 3O₂ (g) → 2SO₃ (g)
In a particular experiment, the reaction of 1.0 g S with 1.0 g O₂ produced 0.80 g of SO₃. The % yield in this experiment is ________.

A) 30
B) 29
C) 21
D) 88
E) 47