[sMiW]

The equation: Fe₂O₃ + 3CO --> 2Fe + 3CO₂ = 26.3 kJ (the amount of heat produced in the reaction)

If the reaction proceeds by the reaction of 20.15g of iron (III) oxide and 5.68 L of carbon monoxide at STP, how much heat in calories will be released?

I know I need to do stoichiometry to find the end result.  I converted 5.68 L of CO to 7.103g of CO.  And I know in the end I will convert my kJ to calories... but I'm stuck as to where to begin.  I know I need to begin with my given masses and use the moles and what not from the balanced equation but in actually beginning I am completely lost.  HELP please! Thanks!!!

[Schrödinger]

You need to know which reactant is the limiting reactant here.
i.e., you need to know which reactant can react completely and which one is in excess.

This is because 26.3 kJ of heat is released only when 1 mole Fe₂O₃ reacts completely with 3 moles CO.