1. Yield
Amount of Products 1

2. Amount of Products Two types of yield Theoretical Practical/Actual2

3. Theoretical and percent yield
=products
Theoretical and percent yield
If a chemical reaction occurs, in theory you can calculate how much of the product is created. This would be the maximum amount that is produced.
What mass of ammonia can be made from g of Nitrogen?
N2 +3H2  2NH3 3

4. Theoretical and percent yield
=products
Theoretical and percent yield
If a chemical reaction occurs, in theory you can calculate how much of the product is created. This would be the maximum amount that is produced.
However, in the real world often not all the possible product are produced in a chemical reaction. 4

5. Why can’t get 100% yield?
Impure reactants
Handling and pouring
Inaccurate measurement techniques
Human Error

6. Theoretical yield
The maximum amount of product that could be produced determined by calculations using the chemical equation.
% yield = 26.5g actual yield
60.0 g Theoretical yield 6

7. Theoretical yield
The maximum amount of product that could be produced determined by calculations using the chemical equation.
Chemistry Marks = actual yield
Theoretical yield 7

8. Theoretical Yield is always large quantity
Actual Yield is always smaller number
% Yield =
Actual Yield
Theoretical Yield
x 100
3.10 8

9. Rearrange the formula to find practical Yield
Rearrange the formula to find theoretical yield
% Yield =
Actual Yield
Theoretical Yield
x 100
3.10 9

10. 2HCl(aq) + Ca(s)  CaCl2(s) + H2(g)
Example:
2HCl(aq) + Ca(s)  CaCl2(s) + H2(g)
Assume the theoretical yield of CaCl2 in this equation were 30 g. If the actual yield of CaCl2 were 25 g, calculate the percentage yield. 10

11. %yield = actual yield X 100%
Theoretical yield
25 g X 100 = 83.3%
30g 11

12. Theoretical Yield is the amount of product that would
result if all the limiting reagent reacted.
Actual Yield is the amount of product actually obtained
from a reaction.
% Yield =
Actual Yield
Theoretical Yield
x 100
3.10 12

13. NH4NO3 --> N2O + 2 H2O
Calculate the percent yield of N2O that was produced by heating 454 g of NH4NO3,
Later it was found that only 131 g of N2O was produced, what is the percent yield?

14. 454 g of NH4NO3 --> N2O + 2 H2O
STEP 1 Calculate the theoretical yield
STEP 2 know actual yield

15. 454 g of NH4NO3 --> N2O + 2 H2O
STEP 3 Calculate the percent yield

16. Mr. Ewan wishes to react 38.34g of powdered aluminum (Al) together with excess of Iron Oxide to produce pure iron. how much Fe will be produced? If it is discovered afterwards that 69.0 g of Fe is obtained what is the percent yield? Al + Fe2O3  Fe+ Al2O3

17. When 250g of C10H22 is burned with 560
When 250g of C10H22 is burned with 560.0L of Oxygen what volume of Carbon Dioxide should be attained. What is the percent yield when 350L of CO2 is actually obtained? C10H22 + O2  CO2 + H2O

19. If 5. 45g of KClO3 are decomposed to form KCl and 1
If 5.45g of KClO3 are decomposed to form KCl and 1.95g of O2 are collected. Calculate the theoretical and percentage yields. 2KClO3  2KCl + 3O2

21. % PURITY
is the amount of pure reactants in the total amount of impure reactants.
Reactants are not pure mostly, so we do not get products as much as we expect.
% Purity =
Pure Reactants
Impure Reactants Mass
x 100
3.10 21

22. % PURITY Impure mass of reactants is given by the experiment
Pure Reactants
Impure Reactants Mass
x 100
Impure mass of reactants is given by the experiment
Only pure part of reactants react, others are left over.
Pure mass of reactants can be calculated from the amount of products
3.10 22

23. % yield and % purity
% yield, calculate toward products % purity, calculate toward reactants

24. If 100. 0 g(impure) of FeO produce 12
If g(impure) of FeO produce 12.0g of Fe according to the reaction. 2FeO + 2C +O2  2Fe + 2CO2 What is % purity of the FeO used?

26. When 15.0 g of CH4 is reacted with an excess of Cl2 according to the reaction CH4 + Cl2 ---> CH3Cl + HCl a total of 29.7 g of CH3Cl is formed,. what is the percentage yield of the reaction?

27. When 15.0 g of CH4 is reacted with an excess of Cl2 according to the reaction CH4 + Cl2 ---> CH3Cl + HCl a total of 29.7 g of CH3Cl is formed,. what is the percentage yield of the reaction? Answer= 62.7

28. When 15.0 g of CH4 is reacted with an excess of Cl2 according to the reaction CH4 + Cl2 ---> CH3Cl + HCl a total of 29.7 g of CH3Cl is formed,. what is the percentage purity of CH4?

30. Expectations 1.Find % yield 2. Find Theoretical yield
3. Calculate Actual yield, from given theoretical yield and % yield
4. Find % purity of reactants

31. Problems
Page 137
Question
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