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At 25 ∘C , the equilibrium partial pressures for the reaction were found to be PA=5.16 bar, PB=5.04 bar, PC=4.11 bar, and PD=4.85 bar . A(g)+2B(g)↽−−⇀4C(g)+D(g) What is the standard change in Gibbs free energy of this reaction at 25 ∘C ? Δ????∘rxn= kJmol

Respuesta :

Answer: 5.85kJ/Kmol.

Explanation:

The balanced equilibrium reaction is

[tex]A(g)+2B(g)\rightleftharpoons 4C(g)+D(g)[/tex]

The expression for equilibrium reaction will be,

[tex]K_p=\frac{[p_{D}]\times [p_{C}]}^4{[p_{B}]^2\times [p_{A}]}[/tex]

Now put all the given values in this expression, we get the concentration of methane.

[tex]K_p=\frac{(4.85)\times [(4.11)^4}{(5.04)^2\times (5.16)}[/tex]

[tex]K_p=10.6[/tex]

Relation of standard change in Gibbs free energy and equilibrium constant is given by:

[tex]\Delta G^o=-2.303\times RT\times \log K_c[/tex]

where,

R = universal gas constant = 8.314 J/K/mole

T = temperature = [tex]25^0C=(25+273)K=298 K[/tex]

[tex]K_c[/tex] = equilibrium constant = 10.6

[tex]\Delta G^o=-2.303\times 8.314\times 298\times \log (10.6)[/tex]

[tex]\Delta G^o=5850.23J/Kmol[/tex]

[tex]\Delta G^o=5.85kJ/Kmol[/tex]

Thus standard change in Gibbs free energy of this reaction is 5.85kJ/Kmol.