Darwinism designates a distinctive form of evolutionary explanation for the history and diversity of life on earth. Its original formulation is provided in the first edition of On the Origin of Species in 1859.
The enthalpy - or internal energy - of a substance is a function of its temperature and pressure. The change in internal energy with respect to change in temperature at fixed pressure is the Specific Heat at constant pressure - cp.
The enthalpy of reaction measures the heat released/absorbed by a reaction that occurs at constant pressure. Review enthalpy of reaction. 1  At constant volume, the heat of reaction is equal to the change in the internal energy of the system.  At constant pressure, the heat of reaction is equal to the enthalpy change of the system.