Question

Calculate the heat of decomposition for this process at constant pressure and 25°C: CaCO3(s) → CaO(s) + CO2(g) The standard enthalpies of formation for the reactant are: ΔHf CaCO3(s) = −1206.9 kJ/mol ; ΔHf CaO(s) = −635.6 kJ/mol; ΔHf CO2(g) −393.5 kJ/mol

Answer 1

Answer:

177.8kJ/mol

Explanation:

In this reaction, the heat of decomposition is the same as the heat of formation. This is a decomposition reaction.

Given parameters:

ΔHf CaCO₃ = -1206.9kJ/mol

ΔHf CaO = −635.6 kJ/mol

ΔHf CO₂ = −393.5 kJ/mol

The heat of decomposition =

                     Sum of ΔHf of products - Sum of ΔHf of reactants

The equation of the reaction is shown below:

     CaCO₃ → CaO + CO₂

The heat of decomposition = [ -635.6 + (-393.5)] - [−1206.9 ]

                                             = -1029.1 + 1206.9

                                             = 177.8kJ/mol