Question

What is the chemical equation of this coupled process? Show that the reaction is in equilibrium. Include physical states ar represent graphite as C(s). chemical equation: MO,(s) + C(s) = M(s) + CO,(g) What is the thermodynamic equilbrium constant for the coupled reaction? 0110 101 backspa 96

Answer 1

Given

MO2 (s) ==> M(s) + O2(g) ΔG° = 289.8 kJ/mol

Temperature = 25°C = (25+273) K = 298 K

Other reaction is conversion of graphite to carbon dioxide

C (s) + O2 (g) ==> CO2 (g) ΔG° = - 394.4 kJ/mol

Chemical equation of coupled process is

Adding both the equations give

MO2 (s) ==> M (s) + O2 (g). ΔG° = 289.8 kJ/mol

C(s) + O2 (g) ==> CO2 (g). ΔG° = -394.4 kJ/mol

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MO2 (s) + C(s) + O2 (g) ==> M(s) + O2(g) + CO₂(g)

MO2 (s) + C(s) ==> M(s) + CO2 (g)

The above one is the chemical equation of coupled process

Now

ΔG⁰ = 289.8 kJ/mol -394.4 kJ/mol

= -104. 6 kJ/mol

We know that

ΔG°=−RT lnK

K = e^( - ΔG/RT)

= e^((104.6 kJ/mol) / (8.314 J/mol K * 298 K))

= 2.16 * 10^(18)

Hence thermodynamic equilibrium constant for the coupled reaction is

2.16 * 10¹⁸