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.
An energy profile of an exothermic reaction. by definition the enthalpy change has a negative value: in an exothermic reaction, gives a negative value for Î´H, since a larger value (the energy released in the reaction) is subtracted from a smaller value (the energy used for the reaction).