Section 11 - Determination of Formulae from Experiments

Question 1

What is empirical formula?

Answer 1

The empirical formula of a compound is the simplest ratio of the atoms of each element in the compound

Question 2

What is molecular formula?

Answer 2

The molecular formula of a compound gives the actual number of atoms of each element in the compound

Question 3

Describe the steps to calculate empirical formulae (5)

Answer 3

1) Write the mass or percentage mass of each element.
2) Find the number of moles of each substance by dividing by the atomic or molecular mass.
3) Divide all answers by the smallest answer.
4) If required: multiply to make up to whole numbers.
5) Use the ratio of atoms to write the formula (this gives the empirical formula).