Question

Calculate ΔG⁰ for the following reactions at 25^oC.

(a) N₂(g) + O₂(g) → 2NO(g)

ΔG⁰ = kJ/mol

(b) H₂O(l) → H₂O(g)

ΔG⁰ =    kJ/mol

(c) 2C₂H₂(g) + 5O₂(g) → 4CO₂(g) + 2H₂O(l)

ΔG⁰ = kJ/mol

Answer 1

ΔG^{0 rxn=} $\sum$ n $\Delta$ Gfo (products)- $\sum$ m $\Delta$ Gfo (products)

$\Delta$ Gfo-std gibbs energy of formation

n,m=coefficients of reactants

$\Delta$ Gfo (N2)=0

$\Delta$ Gfo (O2)=0

$\Delta$ Gfo (NO)=87.6 KJ/mol

ΔG0 rxn=2*87.6 KJ/mol-0=175.2kj/mol

b) $\Delta$ Gfo (H2O L)=-237.14 KJ/MOL

$\Delta$ Gfo (H2O GAS)=0

ΔG0 rxn=0--237.14 KJ/MOL=-237.14 KJ/MOL

C) $\Delta$ Gfo (C2H2))=209 KJ/mol

$\Delta$ Gfo (o2)=0

$\Delta$ Gfo (CO2)=-394.39kj/mol

$\Delta$ Gfo (H2O L)=-237.14 KJ/MOL

$\Delta$ G 0 rxn=[4*(-394.39)+2*(-237.14)]-[2*209+0]=-2051.84-418=-2469.84 kj/mol