1. Determining Mr. Lawson’s Wealth ($)
At the front of the room is a Silver coin
With your phone take a close-up picture of BOTH sides of a coin
Examine the picture CLOSELY and determine how many TOTAL atoms of silver make up Mr. Lawson’s net worth!
DO NOT OPEN THE CASE, Mr. Lawson is a new teacher and does not get paid very much… 

2. Not all materials are pure (entirely made of JUST the chemical we are interested in)
In order to find the purity of a substance we use the following formula…
Percent Purity

3. Answer:

4. Percent Purity Percent Yield

5. Percent Purity Chemicals don’t always exist in pure form.
The purity of a chemical is indicated as the percentage purity.
The impure substance contains another substance to make the mass higher than a pure substance
Percent Purity

6. Percent Purity An analogy
What is the percent purity of gold in gold quartz?
When refined the gold weighs 6.0 g
Gold Quartz Weighs 28.0 g

7. Mass of impure chemical
Percent Purity
Percent Purity =
Mass of pure chemical x
100 %
Mass of impure chemical
What is the percent purity of gold in gold quartz?
When refined the gold weighs 6.0 g
Gold Quartz Weighs 28.0 g

8. Percent Purity What is the percent purity of gold in gold quartz?=
6.0 g pure gold
x 100%
= 21%
28.0 g impure gold
What is the percent purity of gold in gold quartz?
When refined the gold weighs 6.0 g
Gold Quartz Weighs 28.0 g

9. Did you know. Gold Karat is a measure of percentage purity, not weight
Did you know? Gold Karat is a measure of percentage purity, not weight. Karats are often mistaken to be a weight measure used by jewelers. Instead karats are a measure of gold's purity. Pure gold is too malleable to be used as-is by jewelers: a ring made of pure gold would bend and loose its shape and be impossible to wear. So jewelers "dilute" gold by mixing it with other stronger metals. One Karat measures the fineness of gold in 1/24 part which is 4.2%. Hence a 18 karat gold ring is made of 18/24 parts of gold, or 75% gold and 25% other metals. Metals added to gold are of cheaper value, so for equals weight, the price of a jewelry item goes up when the karat count goes up too.
Gold Karat

10. Mass of impure chemical
Percent Purity =
Mass of pure chemical x
100 %
Mass of impure chemical
Percent Purity

11. If 100.0g of FeO produces 12.0g of pure Fe according to the reaction FeO + C + O2  Fe + CO2 What is the percentage purity of FeO used?
Example 1

12. Example 1

13. What mass of impure zinc metal having a purity of 89
What mass of impure zinc metal having a purity of 89.5% is required to produce 975 mL of hydrogen gas at STP according to the reaction: Zn + HCl  ZnCl2 + H2
Example 2

14. Example 2

15. Please collect a % Purity worksheet from the front of the class
Work through the Quick Check and then attempt the practice problem on the back.
Make sure you TRY the practice problem before viewing the answer
Purity Problems

16. Sometimes 100% of the expected amount of products cannot be attained from a reaction. This can occur because:
The reactants may not all react
They may not be 100% pure
Some of the products are lost due to the experiment procedures
Percent Yield

17. Percent Yield Percent Yield = Mass of product attained x 100 %
Mass of product expected
Percent Yield

18. Percent Yield
An analogy
What is the percent yield?
30 kernels

19. What is the percent yield?
Actual yield
Percent yield =
Theoretical yield
30 kernels

20. What is the percent yield?
Actual yield
Percent yield =
Theoretical yield = 30
30 kernels

21. What is the percent yield?
Actual yield = 24
Percent yield =
Theoretical yield = 30
30 kernels
24 popped corn

22. What is the percent yield?
Actual yield = 24
= 80%
Percent yield =
Theoretical yield = 30
30 kernels
24 popped corn

23. Example 1 – The process Given the following equation:
_____ K2PtCl4  + _____ NH3    _____ Pt(NH3)2Cl2  + _____ KCl
Balance the equation.
Determine the theoretical yield of KCl if you start with 34.5 grams of NH3.
Starting with 34.5 g of NH3, and you isolate 76.4 g of Pt(NH3)2Cl2, what is the percent yield?
Example 1 – The process

24. Example 1 – The process Given the following equation:
_____ K2PtCl4  + __2___ NH3    _____ Pt(NH3)2Cl2  + __2___ KCl
Balance the equation.
Determine the theoretical yield of KCl if you start with 34.5 grams of NH3.
Starting with 34.5 g of NH3, and you isolate 76.4 g of Pt(NH3)2Cl2, what is the percent yield?
Example 1 – The process

25. Example 1 – The process Given the following equation:
_____ K2PtCl4  + __2___ NH3    _____ Pt(NH3)2Cl2  + __2___ KCl
Balance the equation.
Determine the theoretical yield of KCl if you start with 34.5 grams of NH g KCl
Starting with 34.5 g of NH3, and you isolate 76.4 g of Pt(NH3)2Cl2, what is the percent yield?
Example 1 – The process

26. Example 1 – The process Given the following equation:
_____ K2PtCl4  + __2___ NH3    _____ Pt(NH3)2Cl2  + __2___ KCl
Balance the equation.
Determine the theoretical yield of KCl if you start with 34.5 grams of NH g KCl
Starting with 34.5 g of NH3, and you isolate 76.4 g of Pt(NH3)2Cl2, what is the percent yield? % yield = 25.1%
Example 1 – The process

27. Example 1

28. Given the following reaction: CH4 + Cl2  CH3Cl + HCl When 15
Given the following reaction: CH4 + Cl2  CH3Cl + HCl When 15.0g of CH4 is reacted with Cl2, a total of 29.7g of CH3Cl is formed. What is the percentage yield of the reaction?
Example 2

29. Example 2

30. What mass of K2CO3 is produced when 1
What mass of K2CO3 is produced when 1.50g of KO2 is reacted according to the reaction, KO2 + CO2  K2CO3 + O2 if the reaction has a 76.0% yield?
Example 3

31. Example 3

32. What mass of CuO is required to make 10
What mass of CuO is required to make 10.0g of Cu according to the reaction NH3 + CuO  N2 + Cu + H2O if the reaction has a 58.0% yield?
Example 4

33. Example 4