Respuesta :
Answer : The value of [tex]\Delta G^o_{rxn}[/tex] for the reaction is -1131.4 kJ
Explanation :
According to Hess’s law of constant heat summation, the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps.
The given main reaction is,
[tex]4CO(g)+2NO_2(g)\rightarrow 4CO_2(g)+N_2(g)[/tex] [tex]\Delta G^o_{rxn}=?[/tex]
The intermediate balanced chemical reaction will be,
(1) [tex]2NO(g)+O_2(g)\rightarrow 2NO_2(g)[/tex] [tex]\Delta G^o_1=-72.6kJ[/tex]
(2) [tex]2CO(g)+O_2(g)\rightarrow 2CO_2(g)[/tex] [tex]\Delta G^o_2=-514.4kJ[/tex]
(3) [tex]\frac{1}{2}O_2(g)+\frac{1}{2}N_2(g)\rightarrow NO(g)[/tex] [tex]\Delta G^o_3=87.6kJ[/tex]
Now we will reverse the reaction 1, multiply the reaction 2 by 2, reverse and half the reaction 3 and then adding all the equations, we get :
(1) [tex]2NO_2(g)\rightarrow 2NO(g)+O_2(g)[/tex] [tex]\Delta G^o_1=72.6kJ[/tex]
(2) [tex]4CO(g)+2O_2(g)\rightarrow 4CO_2(g)[/tex] [tex]\Delta G^o_2=2\times (-514.4kJ)=-1028.8kJ[/tex]
(3) [tex]2NO(g)\rightarrow O_2(g)+N_2(g)[/tex] [tex]\Delta G^o_3=-2\times 87.6kJ=-175.2kJ[/tex]
The expression for [tex]\Delta G^o_{rxn}[/tex] will be,
[tex]\Delta G^o_{rxn}=\Delta G^o_{1}+\Delta G^o_{2}+\Delta G^o_{3}[/tex]
[tex]\Delta G^o_{rxn}=(72.6kJ)+(-1028.8kJ)+(-175.2kJ)[/tex]
[tex]\Delta G^o_{rxn}=-1131.4kJ[/tex]
Therefore, the value of [tex]\Delta G^o_{rxn}[/tex] for the reaction is -1131.4 kJ
