| A | B |
|---|
| Precipitate | A solid that forms from a solution during a chemical reaction |
| Endothermic Reaction | A reaction that absorbs energy in the form of heat |
| Exothermic Reaction | A reaction that releases energy in the form of heat |
| Chemical Equation | A short, easy way to show a chemical reaction, using symbols instead of words |
| Subscript | A number in a chemical formula that tells the number of atoms in a molecule or the ratio of elements in a compound |
| Reactant | A substance that enters into a chemical reaction |
| Product | A substance formed as a result of a chemical reaction |
| Conservation of Mass | The principle stating that matter is not created or destroyed during a chemical reaction |
| Coefficient | A number placed in front of a chemical formula in an equation that indicates how many atoms or molecules of each reactant and product are involved in a reaction |
| Synthesis | A chemical reaction in which two or more simple substances combine to form a new, more complex substance |
| Decomposition | A chemical reaction that breaks down a compound into simpler products |
| Replacement | A reaction in which one element replaces another in a compound, or in which two elements in different compounds trade places |
| Activation Energy | The minimum amount of energy needed to start a chemical reaction |
| Concentration | The amount of one material dissolved in a given amount of another material |
| Catalyst | A material that increases the rate of a chemical reaction by lowering the activation energy |
| Enzyme | A biological catalyst that lowers the activation energy of reactions in cells |
| Inhibitor | A material that decreases the rate of a reaction |
| Combustion | A rapid reaction between oxygen and fuel that produces thermal energy |
| Fuel | A material that releases energy when it burns |
| Ion | An atom or group of atoms that is electrically charged |
| Ionic Bond | The attraction between two oppositely charged ions |
| Polyatomic Ion | An ion that his made of more than one atom |
| Crystal | An orderly, three-dimensional pattern of ions or atoms in a solid |
| Covalent Bond | A chemical bond formed when two atoms share electrons |
| Double Bond | A chemical bond formed when two atoms share two pairs of electrons with each other |
| Molecular Compounds | A compound consisting of molecules of covalently bonded atoms |
| Polar | The description of a covalent bond in which electrons are shared unequally, or of a molecule containing containing polar bonds that do not cancel out |
| Nonpolar | The description of a covalent bond in which electrons are shared equally, or of a molecule containing nonpolar or polar boands that cancel out |
| Mineral | A naturally occuring solid that has a crystal structure and a definite chemical composition; a simple element, which is not organic, that is needed by the body |
