1. Percent Composition

2. Percent Composition from the Chemical Formula % mass = mass of element in 1 mole of compound molar mass of compound Then multiply by 100 to get %

3. Propane (C 3 H 8 ) is one of the compounds obtained from petroleum. Calculate the percent composition of propane. Need to find mass of each element in 1 mole of the compound & mass of the 1 mole of the compound Mass of C in one mole of C 3 H 8 = 36.033 g Mass of H in one mole of C 3 H 8 = 8.064 g Molar mass of C 3 H 8 = 44.097 g

4. % of C = mass of Cx 100 mass of propane (36.033 g/44.097 g) x 100 = 81.713% % of H = mass of Hx 100 mass of propane (8.064 g/44.097 g) x 100 = 18.29 %

5. Results should add up to approximately 100%. If not, you did something wrong!

6. Using % composition Can determine how much of a substance can be produced. For example, how many grams of hydrogen are contained in a 100 g sample of propane?

7. How many grams of hydrogen are contained in a 39.0 g sample of propane? How many grams are carbon?

8. Examples Determine the percent composition of AlPO 4.

9. Lab Directions Complete “Day 1” Instructions (except for acid part) Place a piece of tape with your names on it on the beaker Place the beaker with penny on the cart