Calculate the ΔG°_rxn using the following information.
4 HNO₃(g) + 5 N₂H₄(l) → 7 N₂(g) + 12 H₂O(l) ΔG°_rxn= ?
ΔH°_f (kJ/mol) -133.9 50.6 -285.8
S°(J/mol^∙K) 266.9 121.2 191.6 70.0

Question

Calculate the ΔG°_rxn using the following information. 4 HNO₃(g)+ 5 N₂H₄(l)→ 7 N₂(g)+ 12 H₂O(l)ΔG°_rxn= ? ΔH°_f (kJ/mol)-133.9 50.6 -285.8 S°(J/mol^∙K)266.9 121.2 191.6 70.0

Quizplus · Accepted Answer

- First, we need to calculate the standard entropy change ΔS°rxn using the equation:
ΔS°rxn = ΣS°(products) - ΣS°(reactants)
ΔS°rxn = [7(121.2) + 12(70.0)] - [4(266.9) + 5(191.6) + 14(70.0)]
ΔS°rxn = -442.6 J/K
- Next, we need to calculate the standard enthalpy change ΔH°rxn using the given values of standard enthalpies of formation:
ΔH°rxn = [7(0) + 12(-285.8)] - [4(-133.9) + 5(50.6) + 14(0)]
ΔH°rxn = -4167.8 kJ/mol
- Finally, we can calculate the standard Gibbs free energy change ΔG°rxn using the equation:
ΔG°rxn = ΔH°rxn - TΔS°rxn
We need to convert the units of ΔS°rxn to kJ/mol before plugging in the values:
ΔG°rxn = -4167.8 kJ/mol - (298 K)(-0.4426 kJ/mol/K)
ΔG°rxn = -3297.9 kJ/mol
Rounding to three significant figures, we get:
ΔG°rxn = -3.298 × 10³ kJ/mol, which corresponds to answer choice E.

Calculate the ΔG°rxn Using the Following Information

Calculate the ΔG°_rxn Using the Following Information