Question

Calculate 

(a) ∆G° and 

(b) the equilibrium constant for the formation of NO₂ from NO and O₂ at 298 K 

Where: 

∆_fG° (NO₂) = 52.0 kJ/mol 

∆_fG° (NO) = 87.0 kJ/mol 

∆_fG° (O₂) = 0 kJ/mol 

Answer 1

(a) For the given reaction, 

∆G° = ∆G°( Products) – ∆G°( Reactants)

 ∆G° = 52.0 – {87.0 + 0} 

= – 35.0 kJ mol–1 

(b) We know that, 

∆G° = RT log Kc 

∆G° = 2.303 RT log Kc 

Hence, the equilibrium constant for the given reaction Kc is 1.36 × 106