Answer to Question #346239 in General Chemistry for Ashter

Question

Calculate the Standard Gibbs free energy change for the following reaction at 25 degree celcius.

CaCO₃ + 2HCI(g) > CaCI₂(s) + CO₂(g) + H₂O(I)

ΔG⁰_f (kJ/mol) 1129 -95.3 -750.2 -394.4 -237.2

Answer 1

If the reaction is carried out under standard conditions (unit concentrations and pressures) and at a temperature that corresponds to a table of thermodynamic values (usually 298 K or 25° C), then you can subtract the standard Gibbs Free Energy of Formation ( ΔG ) of the reactants from those of the products:

∆G⁰ = ∆G(H2O) + ∆G(CO₂ ) + ∆G(CaCl₂) - 2*∆G(HCl) - ∆G(CaCO₃):

∆G = -237,2 + (-394,4) + (-750,2) - (2*(-95,3)) - 1129 = -443,4

ANSWER: ∆G = -443,4