This is the 13339th most frequent Spanish word.
químico
"Químico" means "chemical" or "chemist" in English, depending on context.
In this sentence, 'químico' is used as a noun referring to a professional in the field of chemistry.
El químico explicó cómo se realiza la reacción.
The chemist explained how the reaction takes place.
Here, 'químico' is used as an adjective describing 'behavior,' attributing it to the field of chemistry.
Estudio el comportamiento químico de las sustancias.
I study the chemical behavior of substances.
In this case, 'químico' is an adjective describing the type of smell, indicating its artificial or laboratory-associated origin.