Empirical and Molecular Formulae

Question 1

what is the empirical formula?

Answer 1

the smallest whole number ratio of atoms in a compound

Question 2

how to find the empirical formula

Answer 2

1. list all the elements in the compound
2. underneath them write their experimental masses
3. find the number of moles in each element
4. turn the numbers you get into a simple ratio by diving by the smallest number of moles
5. get the ratio in the simplest whole number form - that is the empirical formula

Question 3

what is the molecular formula?

Answer 3

the actual number of atoms of each element in a single molecule - molecular formula are whole number multiples of empirical formula

Question 4

how to find the molecular formula using the empirical formula

Answer 4

1. find the mass of the empirical formula using the RFM of the elements
2. divide the relative molecular mass by the empirical mass
3. then times the empirical formula by the product of step 2