Note that the only requirement for performing this calculation is knowing the amount of the limiting reactant and the ratio of the amount of limiting reactant to the amount of product. Calculate the relative formula masses of the substances in the question. To calculate the theoretical yield of any reaction you must know the reaction.
Write down the number of moles of your limiting reactant.
Next determine the percentage yield. Balance the Chemical Equation. 2 KClO3 s 3 O2 g 2 KCl s The balanced equation reaction shows that 2 moles of KClO3 will produce 3 moles of O2 and 2 moles of KCl. Convert moles of product to mass of product to get your theoretical yield.