Born-Haber cyles...?

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I can do these born-haber cycle questions when asked to calculate the lattice enthalpy of formation but I got given a question of how to calculate the first electron affinity of calcium iodide and I was given a bond dissociation enthalpy value and a value for the enthalpy of formation.

Does anyone know how i would calculate this, using a cycle diagram to help?

Thanks a lot in advance :)

Posted Tue 17th February, 2015 @ 17:08 by :) PurpleJaguar (: - Team GR

2 Answers

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Once you have drawn out the diagram and added in the known values you can use this method. The sum of the clockwise arrows is equal to the sum of the anti cockwise arrows. Therefore, if you have all values on the born haber cycle apart from the first electron affinity of calcium iodide then you can calculate the missing value by adding up the other values in the opposite direction. (Also remember that you keep them same sign if you are going in the direction of the arrow, and change the sign if you are going in the opposite direction to an arrrow). Let me know if this helps, but it sounds like you don't have enough values to draw a cycle. 

Answered Sun 15th March, 2015 @ 15:57 by Former Member
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Thanks this is helpful, thats what i thought that i didnt have enough values, i will ask my teachers at college to make sure, but thanks for your help :)

Answered Sun 12th April, 2015 @ 13:48 by :) PurpleJaguar (: - Team GR