For example , the empirical formula of ethanol may be written C H O because the molecules of ethanol all contain two carbon atoms , six hydrogen atoms , and one oxygen atom .
For molecular compounds , these ratio numbers can all be expressed as whole numbers .
The empirical formula of ethanol may be written C H O because the molecules of ethanol all contain two carbon atoms , six hydrogen atoms , and one oxygen atom .
For molecular compounds , these ratio numbers can all be expressed as whole numbers .