Ch 11 sec 4 .pptx; PERCENT YIELD

Percent Yield

1. Chapter 11: stoichiometry Section 4 : Percent yield

2. Objectives Calculate the theoretical yield of a chemical reaction from data. Determine the percent yield for a chemical reaction

3. limiting reactant &Excess reactant ( in your own words ) limiting reactant: is the reactant that limits the extent of the reaction and determines the amount of the product formed . E xcess reactants Reactants that leftover when a reaction stops

4. Theoretical and Actual Yields The theoretical yield is the maximum amount of product that can be produced from a given amount of reactant . A chemical reaction rarely produces the theoretical yield of product. A chemist determines the actual yield of a reaction through a careful experiment in which the mass of the product is measured

5. The actual yield is the amount of product produced when the chemical reaction is carried out in an experiment . Percent yield is a measure of the efficiency of a Percent yield

6. The actual yield Chemists need to know how efficient a reaction is in producing the desired product. One way of measuring efficiency is by means of percent yield.

7. Percent yield of product : Percent yield of product : is the ratio of the actual yield to the theoretical yield expressed as a percent

8. Answer the following : What is the theoretical yield of NaCl when 20 grams of Cl 2 reacting with excess of sodium iodide a. Balance the equation : NaI ( aq )  Cl 2 (g)  NaCl ( aq )  I 2 (s).

9. If the actual yield of NaCl is find the percent yield ?

10. Percent Yield in the Marketplace : Percent yield is important in the cost effectiveness of many industrial manufacturing processes. For example, the sulfur is used to make sulfuric acid ( H 2 S O 4 ). Sulfuric acid is an important chemical because it is a raw material used to make products such as fertilizers detergents Pigments textiles

11. Formulas for polyatomic ionic compounds: The cost of sulfuric acid affects the cost of many of the consumer items you use every day. The first two steps in the manufacturing process are shown below.

12. The first step, the combustion of sulfur, produces an almost 100% yield . The second step also produces a high yield if a catalyst is used at the relatively low temperature of 400°C. A catalyst : is a substance that speeds a reaction but does not appear in the chemical equation .