Be sure to include all units in your calculations. Mass can be converted to moles using molecular weight.The conversion of volume and mass into number of moles can be done using the density and molecular weight of the material You need to know these quantities in terms of moles to do yield calculations. Usually reactants are measured out by volume or mass. Convert all amounts of reactants and products into moles: To calculate the molecular weight of a molecule, simply add up the masses of the individual atoms.ģ.You will need to know these numbers to do yield calculations. Calculate the molecular weight of each reactant and product: HCl is a catalyst, and does not get consumed in the reaction. Note that in the examples above HCl functions in Any species that is not consumed in the reaction doesn’t figure into the yield calculation. Be sure you can distinguish between reagents, solvents, and catalysts.A balanced equation is needed to correctly determine percentage yield. It is important for the reaction, but isn’t a reagent so it doesn’t figure into the yield calculation. Also notice that acetone is a solvent in this reaction. Therefore, you need twice as much NaI as ClCH2CH2CH2Cl in this reaction. Notice that it takes two moles of NaI to react with every mole of ClCH2CH2CH2Cl, giving one mole of the diiodide product and two moles of NaCl (equation 2 is balanced).
In the above example equation 1 is one way you might see this reaction written, but it is not balanced. Make sure you are looking at a balanced equation before trying to do any yield calculations. Many times reactions are not written in balanced form.To figure out percentage yield you need to know the correct ratio of each of the reactants and products of interest (this is called stoichiometry). Write a balanced equation for the reaction: Follow this step-by-step guide and you will be able to calculate limiting reagent, theoretical yield, and percent yield. Calculating percent yield actually involves a series of short calculations. Yield calculations are common in chemistry.
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