Question:
Following data is given for the reaction: CaCO3 (s) → CaO3 (s) + CO2 (g)
ΔfH⊖ [CaO (s)] = -635.1 kJ mol=-1
ΔfH⊖ [CO2 (g)] = -393.5 kJ mol-1
ΔfH⊖ [CaCO3 (s)] = -1206.9 kJ mol-1
Predict the effect of temperature on the Equilibrium constant of the above reaction.
Solution:
ΔfH⊖ = ΔfH⊖products- ΔfH⊖reactants
ΔfH⊖ = ΔfH⊖ [CaO(s)] + ΔfH⊖ [CO2(g)]- ΔfH⊖ [CaCO3(s)]
= -635.1 -393.5+1206.9 = 178.3 kJ mol-1
=positive
i.e. the reaction is exothermic.
Hence according to Le Chatelier’s Principle on increasing the temperature, the reaction will shift to forward direction.