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A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. [ 1][ 2] Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combined without reacting, they may form a chemical mixture. [ 3]
The United States Supreme Court has defined "composition of matter" to mean "all compositions of two or more substances and all composite articles, whether they be the results of chemical union, or of mechanical mixture, or whether they be gases, fluids, powders or solids." [2] That definition is problematic, however, because composite articles ...
Matter. Hydrogen in its plasma state is the most abundant ordinary matter in the universe. In classical physics and general chemistry, matter is any substance that has mass and takes up space by having volume. [ 1] All everyday objects that can be touched are ultimately composed of atoms, which are made up of interacting subatomic particles ...
Chemistry is the scientific study of the properties and behavior of matter. [1] It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances.
A chemical composition specifies the identity, arrangement, and ratio of the chemical elements making up a compound by way of chemical and atomic bonds . Chemical formulas can be used to describe the relative amounts of elements present in a compound. For example, the chemical formula for water is H 2 O: this means that each molecule of water ...
Atoms are the basic particles of the chemical elements. An atom consists of a nucleus of protons and generally neutrons, surrounded by an electromagnetically bound swarm of electrons. The chemical elements are distinguished from each other by the number of protons that are in their atoms. For example, any atom that contains 11 protons is sodium ...
A chemical property is any of a material's properties that becomes evident during, or after, a chemical reaction; that is, any quality that can be established only by changing a substance's chemical identity. [1] Simply speaking, chemical properties cannot be determined just by viewing or touching the substance; the substance's internal ...
A chemical equation is an expression that gives the identities and quantities of the substances of reactants and products in a chemical reaction. A chemical equation displays the exact mole ratio of reactants and products which is the coefficient. Converting amounts of substances to moles, and vice versa, is the key to all Stoichiometry problems.