Imagine being able to use your computer to make phone calls with the help of special software and a microphoneâand bypassing your phone company and their charges.
So O2 has zero of heat of formation (or enthalpy of formation). The enthalpy of a reaction is defined like this: H = Hproducts-H reactants. The enthalpy of reaction in this case, is the same as the heat of combustion. Hproducts is obtained summing the heats of formation.
Heats of combustion (the energy released when a certain amount of a substance burns in oxygen) have practical importance. A buyer of coal is more interested in the heat of combustion than in the actual weight of the coal. A dietician is interested in knowing the number of calories that are obtained from various foods. Review and/or review Sections 3-4.2, 3-5.1, 5-1, 5-2.1, 6-2, 6-3 in your textbook.