Difference Between Elements and Compounds

"Chemistry is the study of physical matter, which is classified in many different ways, such as state of matter (gas, liquid or solid), chemical form (element, mixture or compound), chemical structure (atoms or molecules, etc.) and so on.

It is important to understand the words element, mixture and compound, because these convey useful information.
substance, which can be used to refer to either an element or a compound - but not to a mixture because a 'substance' always has a definite composition. The most general word is matter which can be used to refer to any of 'substances', 'elements', 'mixtures' or 'compounds'."