Wet limestone is used to scrub SO2 gas from the exhaust gases of power plants. One possible reaction gives hydrated calcium sulfite:
CaCO3(s) + SO2(g) + ½ H2O(ℓ) ⇄ CaSO3 · ½ H2O(s) + CO2(g)
Another reaction gives hydrated calcium sulfate:
CaCO3(s) + SO2(g) + ½ H2O(ℓ) + ½ O2(g) ⇄ CaSO4 · ½H2O(s) + CO2(g)
(a) Which reaction is more product-favored at equilibrium? Use the data in the table below and any other information needed in Appendix L to calculate ΔrG° for each reaction at 25 °C.
(b) Calculate ΔrG° for the reaction
CaSO3 · ½ H2O(s) + ½ O2(g) ⇄ CaSO4 · ½ H2O(s)
Is this reaction product- or reactant-favored at equilibrium?
(a)
Interpretation:
Among the given reactions the reactions that is more favoured at product side should be determined.
Concept introduction:
The Gibbs free energy or the free energy change is a thermodynamic quantity represented by
Here,
Answer to Problem 76GQ
The reaction which is more product-favored at equilibrium is reaction
Explanation of Solution
The value of
Given:
The Appendix L referred for the values of standard entropies and enthalpies.
For reaction
The standard enthalpy change is expressed as,
Substituting the respective values
Also,
Substituting the respective values
Now,
Substituting the value of
For reaction
The standard enthalpy change is expressed as,
Substituting the respective values
Also,
Substituting the respective values
Now,
Substituting the value of
(b)
Interpretation:
The
Concept introduction:
The Gibbs free energy or the free energy change is a thermodynamic quantity represented by
Here,
Answer to Problem 76GQ
The
Thus, the reaction is product-favored at equilibrium.
Explanation of Solution
The value of
Given:
The Appendix L referred for the values of standard entropies and enthalpies.
The standard enthalpy change is expressed as,
Substituting the respective values
Also,
Substituting the values,
Now,
Substitute the value of
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Chapter 18 Solutions
Chemistry & Chemical Reactivity
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