The calorimetry equation is used to find the enthalpy change for a reaction at a constant pressure. It is the product of the mass, the specific heat capacity of the substance and the change in temperature. This type of calorimetry is also known as coffee cup calorimetry.
For calorimetry at constant volume, the equation giving the enthalpy of combustion is the change in internal energy subtracted from the change of moles, multiplied by the gas constant R, multiplied by the temperature. This equation is used in bomb calorimetry. Calorimetry can also be used to find the heat capacity of a substance by dividing the change in energy by the change in temperature.