Q&A for How to Calculate Percent Yield in Chemistry

Percent yield is important because many chemical reactions form byproducts, meaning not all the reactants in the equation actually react. This is important in the manufacturing of products because a low percent yield would indicate that the company is wasting reactants and money.

To increase percent yield, you can either increase the concentration and/or surface area of your reactants. Adding a catalyst to your reaction may also improve percent yield.

If the reaction you are referring to is 2C2H6 + 7O2 --> 4CO2 + 6H2O then you would find the percent yield as follows: 1) 32g C2H6 * (1mol C2H6/30.08g C2H6)* (4mol CO2/2mol C2H6) *(44.01g CO2/1mol CO2) = 93.64g CO2. This is your theoretical yield based on the 32g of C2H6 you started with and the molar ratio between C2H6 and CO2 in your balanced equation. 2) Your experiment produced 44g of CO2, so your actual yield is 44g CO2. % yield = (actual yield/theoretical yield) x 100 (44g CO2/93.64g CO2) x 100 = 46.99%

1) Make sure the chemical equation you are working with is balanced. 2) Determine the mole ratios between the desired reactant and product. You can determine this by the coefficients in front of your desired reactant and product in your balanced equation. 3) Use molar mass of reactant to convert grams of reactant to moles of reactant. 4) Use the mole ratio between the reactant and product (step 2) to convert moles of reactant to moles of product. 5) Use the molar mass of the product to convert moles of product to grams

Multiply the volume by the density of the substance to get the mass.

Well water is composed of 3 atoms, 2 hydrogen and 1 oxygen. Therefore the yield should be 2 parts hydrogen for every 1 part oxygen, so it should be 66% hydrogen, and 33% oxygen.

Actual yield divided by theoretical yield. ( actual ÷ theoretical = % yield ) .

Find the number of moles of the reactants and compare them. The reactant with the least number of moles will be your limiting reactant.

Actual yield is the mass that will be given to you after the experiment or in the exam question. You can use the Mass = MR*Mols equation to find the mols of the actual yield given to you. However, the actual yield will nearly always be given.