Sulfur reacts with oxygen to yield SO3 as shown in the equation below; 2S(g)+ 3O2(g) = 2SO3(g) From part A 7.49 g of S were used. The atomic mass of sulfur is 32.06 g/mol Hence, the number of moles of sulfur used 7.49 / 32.06 = 0.2336 moles The mole ratio of S : SO3 is 1:1 Thus the mass of SO3 will be ( 1 mol of SO3= 80.06 g) 0.2336 moles × 80.06 = 18.7 g
