<Tr> <Td> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> </Td> </Tr> <Ul> <Li> </Li> <Li> </Li> <Li> </Li> </Ul> <P> Enthalpy / ˈɛnθəlpi / (listen) is a property of a thermodynamic system . The enthalpy of a system is equal to the system's internal energy plus the product of its pressure and volume . For processes at constant pressure, the heat absorbed or released equals the change in enthalpy . </P> <P> The unit of measurement for enthalpy in the International System of Units (SI) is the joule . Other historical conventional units still in use include the British thermal unit (BTU) and the calorie . </P>

What type of equation includes the quantity of energy released or absorbed during the reaction