Chapter 9 Lecture Basic Chemistry Fourth Edition 9.4 Percent Yield Learning Goal Given the actual quantity of product, determine the percent yield for a reaction. © 2014 Pearson Education, Inc. Chapter 9 Chemical Quantities in Reactions

Theoretical yield is the amount of product we expect, if all the reactants were converted to the desired product. Actual yield is the amount of product obtained when the reaction takes place. Percent yield is the ratio of actual yield to theoretical yield. © 2014 Pearson Education, Inc. Percent Yield

© 2014 Pearson Education, Inc. On a space shuttle, LiOH is used to absorb exhaled CO 2 and form LiHCO 3. LiOH(s) + CO 2 (g)  LiHCO 3 (s) Calculating Percent Yield On a space shuttle, the LiOH in the canisters removes Co2 from the air.

© 2014 Pearson Education, Inc. Calculating Percent Yield What is the percent yield of LiHCO 3 if 50.0 g of LiOH produces 72.8 g of LiHCO 3 ? LiOH(s) + CO 2 (g)  LiHCO 3 (s) Step 1 State the given and needed quantities. Given: 50.0 g of LiOH, 72.8 g of LiHCO 3 Need: Theoretical yield, LiHCO 3 Percent yield, LiHCO 3

© 2014 Pearson Education, Inc. LiOH(s) + CO 2 (g)  LiHCO 3 (s) 50.0 g72.8 g Actual yield ? Theoretical yield Step 2 Write a plan to calculate the theoretical and percent yield. Calculating Percent Yield grams of LiOH Molar Mass moles of LiOH Molar Mass moles of LiHCO 3 grams of LiHCO 3 Mole– Mole factor

© 2014 Pearson Education, Inc. LiOH(s) + CO 2 (g)  LiHCO 3 (s) 50.0 g 72.8 g Actual yield ? Theoretical yield Step 3 Write the molar mass and mole−mole factors. 1 mole of LiOH = g of LiOH Calculating Percent Yield

© 2014 Pearson Education, Inc. LiOH(s) + CO 2 (g)  LiHCO 3 (s) 50.0 g 72.8 g Actual yield ? Theoretical yield Step 3 Write the molar mass and mole−mole factors. 1 mole of LiHCO 3 = g of LiHCO 3 Calculating Percent Yield

© 2014 Pearson Education, Inc. LiOH(s) + CO 2 (g)  LiHCO 3 (s) 50.0 g 72.8 g Actual yield ? Theoretical yield Step 3 Write the molar mass and mole−mole factors. 1 mole of LiOH = 1 mole of LiHCO 3 Calculating Percent Yield

© 2014 Pearson Education, Inc. Calculating Percent Yield LiOH(s) + CO 2 (g)  LiHCO 3 (s) 50.0 g 72.8 g Actual yield ? Theoretical yield Step 4 Calculate the percent yield by dividing the actual yield by the theoretical yield and multiplying by 100%. Calculation of theoretical yield:

© 2014 Pearson Education, Inc. Calculating Percent Yield LiOH(s) + CO 2 (g)  LiHCO 3 (s) 50.0 g 72.8 g Actual yield ? Theoretical yield Step 4 Calculate the percent yield by dividing the actual yield by the theoretical yield and multiplying by 100%. Calculation of theoretical yield:

© 2014 Pearson Education, Inc. Without proper ventilation and limited oxygen, the reaction of carbon and oxygen produces carbon monoxide. 2C(g) + O 2 (g)  2CO(g) What is the percent yield if 40.0 g of CO is produced when 30.0 g of O 2 is used? Learning Check

© 2014 Pearson Education, Inc. What is the percent yield if 40.0 g of CO is produced when 30.0 g of O 2 is used? 2C(g) + O 2 (g)  2CO(g) 30.0 g 40.0 g Actual yield ? Theoretical yield Step 1 Write the given and needed quantities. Given: 30.0 g of O 2, 40.0 g of CO Need: Theoretical yield, CO Percent yield, CO Solution

© 2014 Pearson Education, Inc. 2C(g) + O 2 (g)  2CO(g) 30.0 g 40.0 g Actual yield ? Theoretical yield Step 2 Write a plan to calculate the theoretical and percent yield. Solution grams of O 2 Molar Mass moles of O 2 Molar Mass moles of CO grams of CO Mole– Mole factor

© 2014 Pearson Education, Inc. 2C(g) + O 2 (g)  2CO(g) 30.0 g 40.0 g Actual yield ? Theoretical yield Step 3 Write the molar mass and mole– mole factors. 1 mole of O 2 = g of O 2 Solution

© 2014 Pearson Education, Inc. 2C(g) + O 2 (g)  2CO(g) 30.0 g 40.0 g Actual yield ? Theoretical yield Step 3 Write the molar mass and mole– mole factors. 1 mole of CO = g of CO Solution

© 2014 Pearson Education, Inc. 2C(g) + O 2 (g)  2CO(g) 30.0 g 40.0 g Actual yield ? Theoretical yield Step 3 Write the molar mass and mole– mole factors. 1 mole of O 2 = 2 moles of CO Solution

© 2014 Pearson Education, Inc. 2C(g) + O 2 (g)  2CO(g) 30.0 g 40.0 g Actual yield ? Theoretical yield Step 4 Calculate the percent yield by dividing the actual yield by the theoretical yield and multiplying by 100%. Calculation of theoretical yield: Solution

© 2014 Pearson Education, Inc. 2C(g) + O 2 (g)  2CO(g) 30.0 g 40.0 g Actual yield ? Theoretical yield Step 4 Calculate the percent yield by dividing the actual yield by the theoretical yield and multiplying by 100%. Calculation of theoretical yield: Solution