To calculate the percent yield of magnesium oxide, we can use the following formula:Percent Yield = Actual Yield / Theoretical Yield 100In this case, the actual yield is the amount of magnesium oxide produced, which is 12.5 grams. The theoretical yield is given as 16.2 grams.Percent Yield = 12.5 grams / 16.2 grams 100Percent Yield = 0.7716 100Percent Yield 77.16%The percent yield of magnesium oxide in this reaction is approximately 77.16%.