Topic 15: Empirical Formula, Video B: Percent Composition Part 1

Question 1

How to calculate molecular formula from percentage composition?

Answer 1

1. Convert percentage composition to grams of each element.
2. Calculate atomic mass to find moles of each element.
3. Determine the simplest integer mole ratio to find EF.
4. With the molecular weight of a given compound determine mass of EF.
5. Compute the ratio of MW to mass of EF.
6. Multiply EF by ratio to get MF.