Simplify the following text for a Grade 10 native English-speaking person.
Original: Chemical similarity ( or molecular similarity ) refers to the similarity of chemical elements , molecules or chemical compounds with respect to either structural or functional qualities , i.e. the effect that the chemical compound has on reaction partners in anorganic or biological settings .
Simplified: Chemical similarity or molecular similarity is a similarity between two different molecules . Two molecules with chemical similarity may do the same or a very similar thing in an organism .