the difference between bond dissociation energy and bond energy
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Bond dissociation energy is the enthalpy change per mole or per bond, when a bond is split by homolytic fission at a temperature of absolute zero.
In homolytic fission a bond is split so that each half retains half of the electrons involved in the bond - so that two free radicals are formed. An example would be splitting methane by pulling away one hydrogen atom with its unpaired electron, leaving a methyl radical with one unpaired electron - you form two reactive groups this way.
Bond energy is quite a bit different - it is related to the enthalpy change required to split a molecule completely into its constituent atoms.
So in methane there are 4 carbon hydrogen bonds, you break them all up, and that requires a certain input of heat per mole - the result is 4 moles of hydrogen and one mole of carbon. The bond energy of the carbon hydrogen bond in methane will be that enthalpy change divided by 4.
Bond energy can be used to estimate enthalpy of formation of molecules to within a few percent, just given tables of bond energies and counting up the number and type of bonds in a given molecule.
So bond dissociation energy is a lot more specific - it will be different depending on the molecule and the particular bond that is split.
In homolytic fission a bond is split so that each half retains half of the electrons involved in the bond - so that two free radicals are formed. An example would be splitting methane by pulling away one hydrogen atom with its unpaired electron, leaving a methyl radical with one unpaired electron - you form two reactive groups this way.
Bond energy is quite a bit different - it is related to the enthalpy change required to split a molecule completely into its constituent atoms.
So in methane there are 4 carbon hydrogen bonds, you break them all up, and that requires a certain input of heat per mole - the result is 4 moles of hydrogen and one mole of carbon. The bond energy of the carbon hydrogen bond in methane will be that enthalpy change divided by 4.
Bond energy can be used to estimate enthalpy of formation of molecules to within a few percent, just given tables of bond energies and counting up the number and type of bonds in a given molecule.
So bond dissociation energy is a lot more specific - it will be different depending on the molecule and the particular bond that is split.
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bond energy refers to the average amount of energy needed to break down all bonds between the same two types of atoms in a compound whereas bond dissociation energy is the amount of energy needed to break down a particular bond in homolysis. In other words, bond energy is the average of bond dissociation energies of all bonds existing between the same types of atoms.
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