1. PERCENT COMPOSITION
SCH3U

2. What is it? Element Percent by Mass Oxygen – 65% Carbon – 18%
Hydrogen – 10%
Nitrogen – 3%
Calcium - 1.5%
Phosphorus - 1.2%
Potassium - 0.2%, Sulfur - 0.2%, Chlorine - 0.2%, Sodium - 0.1%, Magnesium %
Iron, Cobalt, Copper, Zinc, Iodine <0.05 % each
Selenium, Fluorine <0.01 % each

4. What is the percent composition of each colour?
(part / whole) x 100

5. Try this!
A box composed of 60 sections was 15 % blue, 60 % red, and 25 % white. a.) How many sections were blue? b.) How many sections were red? c.) How many sections were white?
Again, students were given five minutes and then strategies were discussed as a class until a systematic method was reached: (percent / 100) x total.

6. Mass percent:
The mass of an element in a compound, expressed as a percent of the total mass of the compound.
Ex. CO
The mass of C = g
The mass of CO = g
The mass percent of C is
42.88%
Ex. CO2
The mass of CO2 = g
27.29%
1 mol of water = 2.02 g H and 16 g of oxygen. Based on atomic mass
To determine the mass percent of each element in the compound, divide the mass of each element by the mass of the compound and multiple by 100%.
Can be determined theoretically or experimentally.
Ex/ CO the mass of C=
the mass of CO=
The mass percent of C is
CO2 the mass of C=
the mass of CO2=

7. Percentage composition:
Is the percent by mass of each element in a compound.
Ex. Percentage composition of NO2 (g)
Mass percent of N = %
Mass percent of O = %
TOTAL = 100%
N = 14.01, o = 32 g, Total: g
Percentage composition of N2O => N = 63.65%, O = 36.25%. Total=100%

8. SAMPLE
A sample of a compound that is found in gasoline has a mass of 35.8 g. The sample contains g of carbon and 5.70 g of hydrogen. What is the percentage composition of the compound? Find the mass % of Carbon and Hydrogen.
Carbon
The mass of C = g
The mass of sample = 35.8 g
= g / 35.8 g X 100%
= 84.1 %
Hydrogen
The mass of H = 5.70 g
= 5.70 g / 35.8 g X 100%
= 15.9 %

9. SAMPLE
A sample of a compound that is found in gasoline has a mass of 35.8 g. The sample contains g of carbon and 5.70 g of hydrogen. What is the percentage composition of the compound? Find the mass % of Carbon and Hydrogen.
Carbon
The mass of C = g
The mass of sample = 35.8 g
= g / 35.8 g X 100%
= 84.1 %
Hydrogen
The mass of H = 5.70 g
= 5.70 g / 35.8 g X 100%
= 15.9 %

10. SAMPLE
A sample of a compound that is found in gasoline has a mass of 35.8 g. The sample contains g of carbon and 5.70 g of hydrogen. What is the percentage composition of the compound? Find the mass % of Carbon and Hydrogen.
Carbon
The mass of C = g
The mass of sample = 35.8 g
= g / 35.8 g X 100%
= 84.1 %
Hydrogen
The mass of H = 5.70 g
= 5.70 g / 35.8 g X 100%
= 15.9 %

11. SAMPLE
A sample of a compound that is found in gasoline has a mass of 35.8 g. The sample contains g of carbon and 5.70 g of hydrogen. What is the percentage composition of the compound? Find the mass % of Carbon and Hydrogen.
Carbon
The mass of C = g
The mass of sample = 35.8 g
= g / 35.8 g X 100%
= 84.1 %
Hydrogen
The mass of H = 5.70 g
= 5.70 g / 35.8 g X 100%
= 15.9 %

12. SAMPLE
A sample of a compound that is found in gasoline has a mass of 35.8 g. The sample contains g of carbon and 5.70 g of hydrogen. What is the percentage composition of the compound? Find the mass % of Carbon and Hydrogen.
Carbon
The mass of C = g
The mass of sample = 35.8 g
= g / 35.8 g X 100%
= 84.1 %
Hydrogen
The mass of H = 5.70 g
= 5.70 g / 35.8 g X 100%
= 15.9 %

13. Sample
Determine the percent composition of Cu2S: Mass percent of Cu = mass of Cu in 1 mol of Cu2S X 100% mass of 1 mol of Cu2S = (2 X g) X 100% g = 79.9 %