In general terms, a substance refers to a particular kind of matter that has uniform properties and composition throughout. It is a more specific term than “matter,” which can encompass anything that occupies space and has mass. Substances are often classified into elements and compounds based on their composition.
Here are two primary categories of substances:
Elements:
An element is a pure substance that consists of only one type of atom. Each element is represented by a unique chemical symbol, and it cannot be broken down into simpler substances by chemical means. Examples of elements include oxygen (O), hydrogen (H), carbon (C), and gold (Au).
Compounds:
A compound is a substance composed of two or more elements chemically combined in fixed proportions. Compounds have unique properties that are different from the properties of their individual elements. The components of a compound are chemically bonded, and compounds can be broken down into their constituent elements through chemical reactions. Water (Hâ‚‚O) and carbon dioxide (COâ‚‚) are examples of compounds.
Substances can exist in various states of matter—solid, liquid, or gas—depending on factors such as temperature and pressure. For example, water (H₂O) can exist as ice (solid), liquid water, or water vapor (gas) while still being the same substance.
It’s important to note that the term “substance” is often used in a broad sense, and the context may determine the level of specificity. In chemistry and physics, the term is often used to refer to elements and compounds, emphasizing their chemical nature and uniform composition.