Question

Consider the reaction: C (s) + O2 (g) -> CO2 (g) If 0.3 moles of carbon are allowed to react with 0.4 moles of molecular oxygen, how many moles of CO2 are formed?

Answer 1

First you need to determine the limiting reagent, in this case it would be the carbon since there's less moles of it than the oxygen.

Answer 2

0.3 mole of C would react completely with 0.3 mole of O2, but there is more O2 present than that, so O2 is in excess and C is the limiting reactant.

(0.3 mol C) x (1 mol CO2 / 1 mol C) = 0.3 mol CO2