Answer : The energy change for the reaction is CsCl is, 95 KJ/mole
Explanation :
The steps involved in the formation of [tex]KBr[/tex] :
(1) Conversion of gaseous potassium atoms into gaseous potassium ions.
[tex]K(g)\overset{\Delta H_I}\rightarrow K^{+1}(g)+1e^-[/tex]
[tex]\Delta H_I[/tex] = ionization energy of potassium = 419 kJ/mol
(2) Conversion of gaseous bromine atoms into gaseous bromine ions.
[tex]Br(g)+1e^-\overset{\Delta H_E}\rightarrow Br^-(g)[/tex]
[tex]\Delta H_E[/tex] = electron affinity energy of bromine = -324 kJ/mol
The overall reaction will be:
[tex]K(g)+Br(g)\rightarrow K^+(g)+Br^-(g)[/tex]
To calculate the overall energy change the expression used is:
[tex]\Delta H=\Delta H_I+\Delta H_E[/tex]
Now put all the given values in this equation, we get:
[tex]\Delta H=419KJ/mole+(-324KJ/mole)[/tex]
[tex]\Delta H=95KJ/mole[/tex]
Therefore, the energy change for the reaction is CsCl is, 95 KJ/mole
