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.
Excess 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 Cl2 reacting with excess of sodium iodide
 a. Balance the equation:
 NaI(aq)  Cl2(g)  NaCl(aq)  I2(s).

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

12. 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

13. 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.

14.  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.