Answer : The energy change for the reaction is CsCl is, 95 KJ/mole
Explanation :
The steps involved in the formation of
:
(1) Conversion of gaseous potassium atoms into gaseous potassium ions.
![K(g)\overset{\Delta H_I}\rightarrow K^{+1}(g)+1e^-](https://tex.z-dn.net/?f=K%28g%29%5Coverset%7B%5CDelta%20H_I%7D%5Crightarrow%20K%5E%7B%2B1%7D%28g%29%2B1e%5E-)
= ionization energy of potassium = 419 kJ/mol
(2) Conversion of gaseous bromine atoms into gaseous bromine ions.
![Br(g)+1e^-\overset{\Delta H_E}\rightarrow Br^-(g)](https://tex.z-dn.net/?f=Br%28g%29%2B1e%5E-%5Coverset%7B%5CDelta%20H_E%7D%5Crightarrow%20Br%5E-%28g%29)
= electron affinity energy of bromine = -324 kJ/mol
The overall reaction will be:
![K(g)+Br(g)\rightarrow K^+(g)+Br^-(g)](https://tex.z-dn.net/?f=K%28g%29%2BBr%28g%29%5Crightarrow%20K%5E%2B%28g%29%2BBr%5E-%28g%29)
To calculate the overall energy change the expression used is:
![\Delta H=\Delta H_I+\Delta H_E](https://tex.z-dn.net/?f=%5CDelta%20H%3D%5CDelta%20H_I%2B%5CDelta%20H_E)
Now put all the given values in this equation, we get:
![\Delta H=419KJ/mole+(-324KJ/mole)](https://tex.z-dn.net/?f=%5CDelta%20H%3D419KJ%2Fmole%2B%28-324KJ%2Fmole%29)
![\Delta H=95KJ/mole](https://tex.z-dn.net/?f=%5CDelta%20H%3D95KJ%2Fmole)
Therefore, the energy change for the reaction is CsCl is, 95 KJ/mole