Thermochemical Terms
 
Thermochemistry: the study of the energy changes that accompany physical or chemical changes in matter

thermal energy: energy available from a substance as a result of the motion of its molecules

chemical system: a set of reactants and products under study, usually represented by a chemical equation

 surroundings: all matter around the system that is capable of absorbing or releasing thermal energy

heat: amount of energy transferred between substances

exothermic: releasing thermal energy as heat flows out of the system

endothermic: absorbing thermal energy as heat flows into the system

temperature: average kinetic energy of the particles in a sample of matter

open system: one in which both matter and energy can move in or out

isolated system:  an ideal system in which neither matter nor energy can move in or out

closed system: one in which energy can move in or out, but not matter

calorimetry: the technological process of measuring energy changes in a chemical system

specific heat capacity: quantity of heat required to raise the temperature of a unit mass of a substance
1°C or 1K
physical change: a change in the form of a substance, in which no chemical bonds are broken

chemical change: a change in the chemical bonds between atoms, resulting in the rearrangement of atoms into new substances

nuclear change:  a change in the protons or neutrons in an atom, resulting in the formation of new atoms