# Percent Yield - drv4chemistry.weebly.com Percent Yield *Notice, kind of like the opposite of Percent Error. Percent Yield Problems The amount of product produced from a reaction based on a calculation is the expected yield (or theoretical yield) The amount of product that is really obtained during the reaction (in a lab or industrial setting) is the actual yield (real life) It is useful to determine what percent of the expected yield was actually obtained. percent yield = expected yield

actual yield x 100% Potential reasons for differences between actual and expected yield 1. some reactants didnt fully react 2. there were side reactions that differ from the reaction on which the expected yield was based 3. some product was lost during recovery or transfer

Example Problem N use otice up ! Yo all u h CS ave 2, d o ple nt n rea t wo y of ge rry oxy nt! ab ge

ou n, c t li mi an tin g A reaction occurs between 500.0 g of carbon disulfide and an excess amount of oxygen gas. The actual mass of sulfur dioxide produced is 768 g. What is the percent yield for this reaction? Step 1: Write the balanced equation. CS2 + 2 O2 2 SO2 + C

Example Problem CS2 + 2 O2 2 SO2 + C Step 2: Determine the expected yield using stoichiometry 500.0 g CS2 x 1 mol CS2 x 2 mol SO2 x 64.07 g SO2 = 841.36 g SO2 76.15 g CS2 1 mol CS2 1 mol SO2 This is how much SO2 you should be able to produce (theoretical yield) Example Problem CS2 + 2 O2 2 SO2 + C

Step 3: Compare the actual yield to the expected yield using the percent yield equation. percent yield = actual yield x 100% expected yield Percent yield = 768 g x 100% = 91.28 % (of expected) 841.36 g