Question | Answer |
Law of Conservation of Mass | the principle that in any closed system subjected to no external forces, the mass is constant irrespective of its changes in form; the principle that matter cannot be created or destroyed. |
Physical Change | a usually reversible change in the physical properties of a substance, as size or shape |
Chemical Change | a usually irreversible chemical reaction involving the rearrangement of the atoms of one or more substances and a change in their chemical properties or composition, resulting in the formation of at least one new substance |
Element | one of a class of substances that cannot be separated into simpler substances by chemical means. See also chart under periodic table. |
Chemical Formula | a representation of a substance using symbols for its constituent elements |
Element (Diatomic) Molecule | diatomic molecules are molecules composed only of two atoms. |
Compound Molecule | The smallest particle into which an element or a compound can be divided without changing its chemical and physical properties |
Chemical Equation | a representation of a chemical reaction using symbols of the elements to indicate the amount of substance, usually in moles, of each reactant and product |
Chemical Reaction | the action caused by the resistance to another action. |
Reactants (of a chemical equation) | any substance that undergoes a chemical change in a given reaction. |
Products (of a chemical equation) | substance that forms as a result of a chemical reacion. |
Coefficient (in a chemical equation) | A number or symbol multiplied with a variable or an unknown quantity in an algebraic term, |
Subscript (in a chemical equation) | A distinguishing character or symbol written directly beneath or next to and slightly below a letter or number. |