What is empirical formula and how is it worked out?

Empirical formula is  the simplest ratio of elements in a formula. chemists use it to make big molecules easier to work with when doing calculations.

An example of a working out an empirical formula is;

Q) Hexane has molecular formula C₆H_14. Work out the empirical formuale of hexane  

A) you need to divide both _subtext numbers by the largest number that goes into both. if this number isnt obvious to you start with a number you know goes into both, e.g 2 

using that here we would divide both ₆ and ₁₄ by 2 and get C₃H₇ 

as 3 and 7 dont have any more numbers that go into both (except 1) C₃H₇ is the empirical formula