In the homework for lecture #8, Problem #7, a version of Pauling's electronegativity equation is used that is valid for bond energies given in kJ. Using the homework solution, I managed to put this equation together.$$(\chi_A-\chi_B)^2 = \frac{1}{96.3} \bigg(E_{d(A-B)} - \sqrt{E_{d(A-A)} * E_{d(B-B)}}\bigg)$$$$Some \space Unknown \space Magic \space Number\approx \frac{1}{96.3} \hspace{12pt} \bigg| \hspace{12pt}\space E_{d(Bond)} = E_{dissociation(Bond)}$$Where did this equation come from? I do not think it was covered in any of the lectures up to this point.

Question

In the homework for lecture #8, Problem #7, a version of Pauling's electronegativity equation is used that is valid for bond energies given in kJ.  Using the homework solution, I managed to put this equation together.$$(\chi_A-\chi_B)^2 = \frac{1}{96.3} \bigg(E_{d(A-B)} - \sqrt{E_{d(A-A)} * E_{d(B-B)}}\bigg)$$$$Some \space Unknown \space Magic \space Number\approx \frac{1}{96.3} \hspace{12pt} \bigg| \hspace{12pt}\space E_{d(Bond)} = E_{dissociation(Bond)}$$Where did this equation come from?  I do not think it was covered in any of the lectures up to this point.

anonymous · Answer

I vaguely seem to recall reading about something like this equation in the textbook.  I can't seem to find the Pauling electronegativity equation in the book, so I may be vaguely remembering something else.

The magic number 1/96.3 seems to have something to do with expressing bond energies in kJ, but I have no idea where it comes from or why this value is used.  Evidently Pauling expressed values in kcal, and the versions of this equation I find on the net are a little different from the version used to solve the homework problem.