The heat capacity (C) is the ratio of the heat added (Q) or subtracted to an object to the resulting temperature change (≡ Q/ΔT with units J ˣ K -1 ). The specific heat (capacity) is the heat capacity per unit mass of a material. C P and C V are the heat capacities at constant pressure (isobaric, C P = (δU/δT) P ) and constant volume (isochoric, C V = (δU/δT) V ) respectively. The specific heat is the amount of heat needed to raise the temperature of one kilogram of mass by 1 kelvin. The molar heat capacity is the heat capacity per mole of a pure substance.
In an exergonic reaction, the chemical bonds formed are stronger than those broken. When there is an exothermic reaction, the temperature of the surroundings increase. Two related terms are endergonic reaction and endothermic reaction. An endergonic reaction refers to energy being absorbed from the surroundings. When there is an endergonic reaction, the chemical bonds formed are weaker than those broken. An endothermic reaction describes when an endergonic reaction occurs and the energy being absorbed from the surroundings is heat energy. When there is an endothermic reaction, the temperature of the surroundings decrease.