1. Welcome to Chemistry!!

2. Candy Question
You will be given a package of candy. It is your job to find the mass percent of each color.
Remember that percents are written as a partial amount out of a whole amount:
Example: 50/100 = 50% ¾ = 75%

3. Candy Question
We can use this same technique to find the mass percent in different compounds.

4. Percent Composition
We can use the information from the formula of compound to find the percent composition
We use the mass of each element in 1 mole of the compound

5. Percent Composition
For example, we are going to use the compound ethanol with the formula C2H5OH
First find the molecular weight of ethanol

6. Percent Composition Mass of C = 12.01 x 2 = 24.02
Mass of H = x 6 = 6.048
Mass of O = x 1 = 16.00
Sum = 46.07g = molecular mass

7. Percent Composition Solve for mass percent of each element
MP of C = 24.02/46.07 x 100%
MP of C = 52.14%

8. Percent Composition MP of H = 6.048/46.07 x 100% MP of H = 13.13%
MP of O = 16.00/46.07 x 100%
MP of O = 34.73%

9. Percent Composition
The easiest way to check is to make sure that all your percents total 100%!!!