- activated complex: transitional structure that results from an effective collision and that persists while old bonds are breaking and new bonds are forming
- activation energy: the minimum energy required to transorm the reactants into an activated complex
- calorimeter: unit of measure of the energy absorbed or released as heat in a chemical or physical change
- catalysis: the action of a catalyst
- catalyst: a substance that changes the rate of a chemical reaction without itself being permanently consumed
- chemical kinetics: the area of chemistry that is concerned with reaction rates and reaction mechanisms
- collision theory: set of assumptions regarding collisions and reactions
- enthalpy change: the amount of energy absorbed or lost by a system as heat during a process at constant pressure
- entropy: a measure of the degree of randomness of the particles, as as molecules, in a system
- free energy: combined enthalpy-entropy function of the system
- free-energy change: the difference between the change in enthalpy and the product of the Kelvin temperature and the entropy change
- heat: the energy transferred between samples of matter because of a difference in their temperatures
- heat of combustion: the energy released as heat by the complete combustion of one mole of a substance
- heat of reaction: the quantity of energy released or absorbed as heat during a chemical reaction
- Hess's law: the overall enthalpy change in a reaction equal to the sum of enthalpy changes for the individual steps in the process
- heterogeneous catalyst: a catalyst that is not in the same phase as all the reactants and products in a reaction system
- heterogeneous reactions: involves reactants in two different phases
- homogeneous catalyst: a catalyst that is in the same phase as all the ractants and products in a reaction system
- homogeneous reaction: a reaction whose reactants and products exist in a single phase
- intermediates: species that appear in some steps but not in the net equation
- joule: the SI unit of heat, as well as all other forms of energy
- molar heat of formation: the energy released or absorbed as heat when one mole of a compound is formed by combination of its element
- rate law: an equation that relates reaction rate and concentrations of reactants
- rate-determining step: the slowest-rate step for the chemical reaction
- reaction mechanism: the step-by-step sequence of reactions by which the overall chemical change occurs
- reaction rate: the change in concentration of reactants per unit time as a reaction proceeds
- specific heat: the amount of energy required to raise the temperature of one gram of substance by one Celsius degree or one Kelvin
- temperature: a measure of the average kinetic energy of the particles in a sample of matter
- thermochemical equation: an equation that includes the quantity of energy released or absorbed as heat during the reaction as written
- thermochemistry: the study of the transfers of energy as heat that accompany chemical reactions and physical changes