The equation for the reaction is

2S(g) + 3O2(g) ---> 2SO3(g)

Consider a mixture of sulfur atoms and dioxygen molecules in a closed container below:

For each of the following explain why the representation is correct or incorrect. (Click on a diagram for an answer.)

This diagram is correct. The total number of sulfur and oxygen atoms are conserved in this diagram. Notice there is an excess of sulfur atoms. The original mixture did not have enough oxygen atoms to react with all of hte sulfur. So dioxygen is the limiting reagent and sulfur is in excess.