We explain what a substance is in chemistry, what types exist and differences with compounds. Also, the substance in philosophy.
In chemistry, a substance is a homogeneous type of matter.What is a substance?
A substance is the most essential part of something, that is, the matter in its most stable, specific and invariable state. It is not easy to define the substantial, and this is largely responsible for the philosophy, on the one hand, and the chemistry, on the other: the first from a conceptual point of view, the second from the point of view scientific.
When we refer to the substance of something, we are pointing to its essential, central, purest part: that which is not composed of other substances, but of itself and, therefore, also the most important, defining, nuclear part.
For this reason, chemistry distinguishes between substances and compounds, since by reacting two or more substances we can obtain a compound. However, depending on the nomenclature, it is possible to speak also in these cases of "simple substances" and "compound substances".
In the same way, we use this term to refer to things that have value in themselves, that is, that contribute something, that are dense. "An insubstantial comment", for example, is a comment that has no substance and, therefore, has no value, it is empty.
In another sense, "a substantial dinner" is a nutritious meal, abundant, full of content and therefore good, desirable.
Substance in chemistry
Chemistry defines substances as those homogeneous types of matter, endowed with a defined and fixed chemical composition. Substances are composed of molecules, and you are in turn of atoms, that is, of particles chemically bonded to each other in a fixed and stable way.
Substances are different from mixtures, which are combinations, distinguishable or not, of two or more substances to form a single matter (called, depending on the case, solution, dissolution, alloy, etc.).
Something different happens when two substances react chemically, and they combine through molecular bonds and changing their nature. Thus it gives rise to a compound (or compound chemical substance), that is to say, to a new chemically stable substance.
Examples of chemicals are:
- Simple (formed by the same type of element). Gold, oxygen, nitrogen, argon, iron, fullerene.
- Composite (made up of two or more types of elements). Water, glucose, carbon dioxide, ammonia.
Chemicals cannot be separated by any physical method of separation (as the decantation, the filtration wave evaporation). Each substance has specific properties, such as melting point, Boiling point Y density. Also each substance exists in a State of aggregation determined (solid, liquid, gaseous, plasma).
Substance in philosophy
Philosophically speaking, the substance of things is their essence or their being, understood as an intrinsic property of the thing, something that is "underneath" or that "underlies" the accidental qualities of matter. By structurally changing a substance, we are basically exchanging one substance for another.
Since ancient times there has been an attempt to define what the substance is. Aristotle (4th century BC) defined it as “that which is neither predicated of a subject, nor is present in a subject, for example, a man or an individual horse ”. While René Descartes (1596-1650), one of the fathers of modern philosophy, defined it as “everything that does not need anything else to exist”.