10 g of S is mixed with 41 g of O and heated until S is changed to SO2. What mass of O is unreacted

Sulfur dioxide is 50.1% sulfur and 49.9% oxyygen by mass. Suppose that 10 grams of sulfur
is mixed with 41 grams of oxygen and heated
until all the sulfur is converted to sulfur dioxide.
What mass of oxygen remains unreacted?
Answer in units of g

S + O2 ----> SO2. Mole ratios are all 1 to 1

10 g S = 0.3119 mol

41 g of O2 = 1.28 mol

Since There is WAY more mol of O2 than is needed the S is the limiting reagent. It will be completely used up. So if 0.3119 mol of S is used up then only 0.3119 mol of O2 will be used.

That leaves 1.28 - 0.3119 or 0.96935 mol of O2 unreacted.

0.06935 mol x 32.00 g/mol = 31.02 g not used.