The Student Room Group

Born Haber cycle

Hey! Can i just check that bond dissociation enthalpy occurs when ONE MOLE of gaseous bonds are broken forming gaseous atoms. And enthalpy change of atomisation occurs when ONE MOLE of gaseous atoms are formed from element in their standard state?? For in my booklet its written down that Cl2(g) to 2Cl(g) is enthalpy of atomisation and I thought because two moles are formed it would be bond dissociation enthalpy as enthalpy of atomisation for chlorine would instead be 1/2 Cl2(g)-->Cl(g). Thanks for the help, hopefully ive explained it clearly.
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Original post by dafydd888
For in my booklet its written down that Cl2(g) to 2Cl(g) is enthalpy of atomisation


You're correct. That is 2x DH atomisation (as 2 mol of atoms are formed), which in this case is equal to bond enthalpy.

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