How can you tell the difference between an ester, ketone, carboxylic acid, aldehyde, amines, amides and phenol?
Each is just an additional part to a molecule.
Amines (I, II, and III)
By Phenol I assume you ment an alcohol:
Now we can see the differences. An ester is a ketone where one of the carbons is bonded to an oxygen that is bonded to something else. A carboxylic acid is where an ester's oxygen is bonded with a hydrogen. Aldehyde is a ketone where one of the bonds on the carbon is a hydrogen.
Amines get complicated because there are 3 types, Primary, Secondary, and Tertiary. The first is an NH2 group. The Second is two bonds leading to an NH group. The Tertiary is a trigonal plainer bond of three groups to one Nitrogen.
Alcohols are simply an OH group bonded to a carbon.
As simple as that. Hope this helped.