| Chemical equilibrium | the state reached by a reaction mixture when the rate of forward reaction and that of the reverse reaction have become equal |
| Endothermic process | a chemical reaction or physical change in which heat is absorbed |
| Equilibrium constant Kc | the value obtained for the equilibrium-constant expression when equilibrium concentrations are substituted |
| Exothermic process | a chemical reaction or physical change in which heat is evolved |
| Le Chatelier's principle | a principle stating that when a system in equilibrium is disturbed by a change of temperature, pressure, or concentration variable, the system shifts in equilibrium composition in a way that tends to counteract this change of variable |
| Pressure | the force exerted per unit area of surface |
| Product | a substance that results from a chemical reaction |
| Reactant | a starting substance in a chemical reaction |