Im doing my chemistry project And I dont know how much energy will take to destroy some bonds how I can calkulate it? for example 2Al2O3 ->4Al +
3O2 how I can calculate Al-O bond energy? blogfast25 - 10-4-2016 at 11:27
Im doing my chemistry project And I dont know how much energy will take to destroy some bonds how I can calkulate it? for example 2Al2O3 ->4Al +
3O2 how I can calculate Al-O bond energy?
You may just have chosen the wrong example but for Al2O3 the concept of bond energy (bond enthalpy) isn't really applicable.
In Al2O3 no Al-O bonds exist in the narrow sense of the word: alumina forms an ionic lattice of 2 mol Al3+ cations
and 3 mol O2- anions per mol alumina. That lattice is held together by the electrostatic attractions between the cations and anions.
Compare this to e.g. H2O, in which each O atom covalenty bonds to two hydrogen atoms, to form a H2O molecule.DraconicAcid - 10-4-2016 at 12:05
Bond enthalpies are only useful for gas-phase reactions.MeshPL - 12-4-2016 at 11:12
But you can calculate the enthlapy of the reaction easily using data given in tables you can find on the Internet. Al2O3 has enthalpy of formation
equal to -1675,7 kJ/mol. O2 and Al have 0 (as they are pure elements). You can easily find out that to break a mole of Al2O3 you need to supply it
with 1675,7kJ. I'm not sure if molar enthropy would play a part in that. If it does, you will need to specify temperature, and mentioned value would
be incorrect, but for 1atm 25°C it would be 1582,3kJ per mole.
