how many moles of SO3 will be produced from 9.1 mol O2
Here is an example stoichiometry problem I've posted. You can skip the step of converting grams to moles since you are given moles in the problem.
http://www.jiskha.com/science/chemistry/stoichiometry.html
To determine the number of moles of SO3 produced from 9.1 mol of O2, we need to use the balanced chemical equation for the reaction that produces SO3 from O2.
The balanced chemical equation is:
2 SO2 + O2 -> 2 SO3
From the balanced equation, we can see that for every 1 mole of O2, 2 moles of SO3 are produced. Therefore, we need to find the mole ratio between O2 and SO3 to calculate the number of moles of SO3 formed.
Since the mole ratio between O2 and SO3 is 1:2, we can set up a proportion to find the number of moles of SO3:
(9.1 mol O2) x (2 mol SO3 / 1 mol O2) = 18.2 mol SO3
Therefore, 9.1 mol of O2 will produce 18.2 mol of SO3.