Answer
(a)mass of oxygen in sulfur dioxide=9.04g
(b)the mass of oxygen in sulfur trioxide=13.56g
Work Step by Step
First, we calculate the number of moles of sulfur using the formula:
Number of moles of sulfur=$\frac{mass}{molecular mass}=\frac{9.04}{32}=0.2825mol$
(a)1 mol of $SO_2$ contains 1mole of S and 2 moles of O. So, for 0.2825mol of S we will have:
$0.2825mol(S)\times\frac{2mol(O)}{1mol(S)}=0.565mol(O)$
We then calculate the mass of oxygen using the formula:
mass=$molar mass\times number of moles=16\times0.565=9.04g$
(b)1 mol of $SO_3$ contains 1mole of S and 3 moles of O. So, for 0.2825mol of S we will have:
$0.2825mol(S)\times\frac{3mol(O)}{1mol(S)}=0.8475mol(O)$
We then calculate the mass of oxygen using the formula:
mass=$molar mass\times number of moles=16\times0.8475=13.56g$
