Question | Answer |
laws of conservation of mass | the mass of an isolated system will remain constant over time |
physical change | a usually reversible change in the physical properties of a substance |
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 |
element (diatomic) molecule | are molecules composed only of two atoms |
compound molecule | when 2 or more atoms are chemically combined |
chemical equations | shorthand form of writing what reactants are used and what products are formed in a chemical reaction |
chemical reaction | process that produces chemical change, creating a new substance that have different properties |
reactants
(in a chemical equation) | substances that go through a chemical change |
products
(in a chemical equation) | substances that result from a chemical change |
coefficient
(in a chemical equation) | tells the number of molecules |
subscript
(in a chemical equation) | tells the number of a certain type of atom in one molecule |
chemical formula | a representation of a substance using symbols for its constituent elements |
element | substances that can not be broken down into smaller substances |