| A | B |
|---|
| molar mass | A term used to refer to the mass of a mole of any substance. |
| mole (mol) | The amount of a substance that contains 6.02 × 1023 representative particles of that substance. |
| representative particle | The smallest unit into which a substance can be broken down without a change in composition usually atoms, molecules or ions. |
| Avogadro’s number | The number of representative particles contained in one mole of a substance. |
| molar volume | The space occupied by 1 mole of a gas at standard temperature and pressure (STP). |
| Avogadro’s hypothesis | Equal volumes of gases at the same temperature and pressure contain equal numbers of particles. |
| percent composition | The percent by mass of each element in a compound. |
| empirical formula | A formula with the lowest whole-number ratio of elements in a compound. |
| chemical equation | An expression representing a chemical reaction; the formulas of the reactants are connected by an arrow with the formulas for the products. |
| skeleton equation | A chemical equation that does not indicate the relative amounts of reactants and products. |
| catalyst | A substance that increases the rate of reaction by lowering the activation-energy barrier. |
| coefficient | A small whole number that appears in front of a formula in a balanced chemical equation. |
| standard temperature and pressure (STP) | The conditions under which the volume of a gas is usually measured. |
| balanced equation | A chemical equation in which mass is conserved; each side of the equation has the same number of atoms of each element. |
| inhibitor | A substance that interferes with the action of a catalyst. |
| combination (synthesis) reaction | A chemical change in which two or more substances react to form a single new substance. |
| decomposition reaction | A chemical change in which a single compound is broken down into two or more simpler products. |
| single-replacement reaction | A chemical change in which one element replaces a second element in a compound. |
| double-replacement reaction | A chemical change that involves an exchange of positive ions between two compounds. |
| combustion reaction | A chemical change in which an element or a compound reacts with oxygen often producing energy in the form of heat and light. |
| activity series | A list of elements in order of decreasing activity. |
| endothermic reaction | Energy must be provided for the reaction to take place. |
| exothermic reaction | Some form of energy is given off by the reaction. |
| precipitate | Often seen as a non-soluable solid that forms during a double-replacement reaction. |
