Dr. Steve Rapp, 2005
Enthalpy Changes for Chemical
When carbon (as coal) is burned energy is released:
C + O
The energy released is called the enthalpy of
H. In this case,
H = -393.5 kJ.
The change in enthalpy that occurs when a
chemical reaction takes place is due primarily to the
energy required to break the chemical bonds in the
reactants and the energy produced by forming the
chemical bonds in the product.