Chemistry 16.3 Slide 1 of 36 12.3 Limiting Reagent and Percent Yield If a carpenter had two tabletops and seven table legs, he could only build one four-legged table. The number of table legs is the limiting factor in the construction of four-legged tables. Similarly, in chemistry, the amount of product made in a chemical reaction may be limited by the amount of one or more of the reactants. © Copyright Pearson Prentice Hall Slide 2 of 36 12.3 Limiting Reagent and Percent Yield > Limiting and Excess Reagents Limiting and Excess Reagents How is the amount of product in a reaction affected by an insufficient quantity of any of the reactants? Slide 3 of 36 © Copyright Pearson Prentice Hall 12.3 Limiting Reagent and Percent Yield > Limiting and Excess Reagents In a chemical reaction, an insufficient quantity of any of the reactants will limit the amount of product that forms. The limiting reagent is the reagent that determines the amount of product that can be formed by a reaction. Slide 4 of 36 © Copyright Pearson Prentice Hall 12.3 Limiting Reagent and Percent Yield > Limiting and Excess Reagents In the reaction of nitrogen and hydrogen, hydrogen is the limiting reagent. Nitrogen is the reagent that is not completely used up in the reaction. The reagent that is not used up is called the excess reagent. Slide 5 of 36 © Copyright Pearson Prentice Hall 12.3 Limiting Reagent and Percent Yield > Limiting and Excess Reagents The Chemical Equation for the Preparation of Ammonia Slide 6 of 36 © Copyright Pearson Prentice Hall Limiting Reagent and Percent Yield > Limiting and Excess Reagents Animation 13 Apply the limiting reagent concept to the production of iron from iron ore. Slide 7 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.7 Slide 8 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.7 Slide 9 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.7 Slide 10 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.7 Slide 11 of 36 © Copyright Pearson Prentice Hall Practice Problems for Sample Problem 12.7 Problem Solving 12.25 Solve Problem 25 with the help of an interactive guided tutorial. © Copyright Pearson Prentice Hall Slide 12 of 36 SAMPLE PROBLEM 12.8 Slide 13 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.8 Slide 14 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.8 Slide 15 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.8 Slide 16 of 36 © Copyright Pearson Prentice Hall Practice Problems for Sample Problem 12.8 Problem Solving 12.28 Solve Problem 28 with the help of an interactive guided tutorial. Slide 17 of 36 © Copyright Pearson Prentice Hall 12.3 Limiting Reagent and Percent Yield > Percent Yield Percent Yield What does the percent yield of a reaction measure? Slide 18 of 36 © Copyright Pearson Prentice Hall 12.3 Limiting Reagent and Percent Yield > Percent Yield The percent yield is a measure of the efficiency of a reaction carried out in the laboratory. A batting average is actually a percent yield. Slide 19 of 36 © Copyright Pearson Prentice Hall 12.3 Limiting Reagent and Percent Yield > Percent Yield • The theoretical yield is the maximum amount of product that could be formed from given amounts of reactants. • In contrast, the amount of product that actually forms when the reaction is carried out in the laboratory is called the actual yield. Slide 20 of 36 © Copyright Pearson Prentice Hall 12.3 Limiting Reagent and Percent Yield > Percent Yield The percent yield is the ratio of the actual yield to the theoretical yield expressed as a percent. Slide 21 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.9 Slide 22 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.9 Slide 23 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.9 Slide 24 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.9 Slide 25 of 36 © Copyright Pearson Prentice Hall Practice Problems for Sample Problem 12.9 Problem Solving 12.29 Solve Problem 29 with the help of an interactive guided tutorial. © Copyright Pearson Prentice Hall Slide 26 of 36 SAMPLE PROBLEM 12.10 Slide 27 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.10 Slide 28 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.10 Slide 29 of 36 © Copyright Pearson Prentice Hall SAMPLE PROBLEM 12.10 Slide 30 of 36 © Copyright Pearson Prentice Hall Practice Problems for Sample Problem 12.10 Problem Solving 12.31 Solve Problem 31 with the help of an interactive guided Slide tutorial. 31 of 36 © Copyright Pearson Prentice Hall 12.3 Section Quiz. Assess students’ understanding of the concepts in Section 12.3. Continue to: -or- Launch: Section Quiz Slide 32 of 36 © Copyright Pearson Prentice Hall 12.3 Section Quiz. 1. In the reaction 3NO2 + H2O 2HNO3 + NO, how many grams of HNO3 can form when 1.00 g of NO2 and 2.25 g of H2O are allowed to react? a. 0.913 g b. 0.667 g c. 15.7 g d. 1.37 g Slide 33 of 36 © Copyright Pearson Prentice Hall 12.3 Section Quiz. 2. How many grams of H2O can be formed from 24.0 g O2 and 6.00 g H2? a. 30.0 g b. 27.0 g c. 54.0 g d. 13.5 g Slide 34 of 36 © Copyright Pearson Prentice Hall 12.3 Section Quiz. 3. Octane burns according to the following equation. 2C8H18 + 25O2 16CO2 + 18H2O What is the percent yield if 14.6 g of CO2 are produced when 5.00 g of C8H18 are burned? a. 106% b. 94.8% c. 34.2% d. 62.5% Slide 35 of 36 © Copyright Pearson Prentice Hall Limiting Reagent and Percent Yield > Concept Map 12 Solve the Concept Map with the help of an interactive guided tutorial. Slide 36 of 36 © Copyright Pearson Prentice Hall END OF SHOW