1. Percentage Composition

2. Percentage composition
Indicates the relative amount of each element present in a compound.

3. Calculating percentage composition
Step 1 : Calculate molar mass
Step 2 : Divide the subtotal for each element’s mass by the molar mass.
Step 3: Multiply by 100 to convert to a percentage.

4. What is the percent composition of water?
Step 1 Calculate the molar mass of water, H2O.
H: (1.01)= 2.02
O: (16.0)= 16.0
________
18.02 g/mol

6. Example 2
Calculate the percentage composition of sucrose , C12H22O11.

7. Example 3
Find the percentage composition of hydrogen in sulfuric acid.