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Difference between bond enthalpies and standard enthalpies of formation

Posted: Thu Jan 26, 2017 8:50 pm
by divya_devineni_2E
What is the difference between bond enthalpies and standard enthalpy of formation?

Re: Difference between bond enthalpies and standard enthalpies of formation

Posted: Thu Jan 26, 2017 10:10 pm
by TramHo2G
Hi,

Bond enthalpy(aka bond energy) is the amount of energy required to break one mole of the stated bond. For example, the bond energy of a O-H single bond is 463 kJ/mol. This means that it requires 463 kJ of energy to break one mole of O-H bonds.

When all reactants and products are in their standard state at 1 atm, the reaction enthalpy is called the standard reaction enthalpy.
The standard reaction enthalpy for the formation of 1 mole of a substance from its elements in their most stable form is called the standard enthalpy of formation. The most stable form is zero. This information was found in the Course Reader on page 17.