Table of contents

1. Intro to General Chemistry3h 48m
2. Atoms & Elements4h 16m
3. Chemical Reactions4h 10m
4. BONUS: Lab Techniques and Procedures1h 38m
5. BONUS: Mathematical Operations and Functions48m
6. Chemical Quantities & Aqueous Reactions3h 53m
7. Gases3h 49m
8. Thermochemistry2h 37m
9. Quantum Mechanics2h 58m
10. Periodic Properties of the Elements3h 9m
11. Bonding & Molecular Structure3h 29m
12. Molecular Shapes & Valence Bond Theory1h 57m
13. Liquids, Solids & Intermolecular Forces2h 23m
14. Solutions3h 1m
15. Chemical Kinetics2h 53m
16. Chemical Equilibrium2h 29m
17. Acid and Base Equilibrium5h 1m
18. Aqueous Equilibrium4h 47m
19. Chemical Thermodynamics1h 50m
20. Electrochemistry2h 42m
21. Nuclear Chemistry2h 36m
22. Organic Chemistry5h 7m
23. Chemistry of the Nonmetals2h 39m
24. Transition Metals and Coordination Compounds3h 16m

19. Chemical Thermodynamics

Gibbs Free Energy And Equilibrium

General Chemistry

19. Chemical Thermodynamics

Gibbs Free Energy And Equilibrium

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Multiple Choice

Estimate the value of the equilibrium constant at 660 K for the reaction 2NO2(g) ⇌ N2O4(g) given that ΔG°f for BrCl(g) is -1.0 kJ/mol and the standard molar entropy, S°, for BrCl(g) is 240.0 J/mol⋅K. Assume ΔH°f for N2O4(g) is -9.2 kJ/mol and ΔH°f for NO2(g) is 33.2 kJ/mol.

K = 5.60

K = 0.15

K = 3.45

K = 1.25

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Verified step by step guidance

First, identify the relevant thermodynamic equation to relate the equilibrium constant (K) to the standard Gibbs free energy change (ΔG°) for the reaction: ΔG° = -RT ln(K), where R is the universal gas constant (8.314 J/mol⋅K) and T is the temperature in Kelvin.

Calculate the standard Gibbs free energy change (ΔG°) for the reaction using the formula: ΔG° = ΣΔG°f(products) - ΣΔG°f(reactants). Since ΔG°f for N2O4(g) and NO2(g) are not directly given, use the relation ΔG° = ΔH° - TΔS° to find ΔG°f for each species.

Determine the standard enthalpy change (ΔH°) for the reaction: ΔH° = ΣΔH°f(products) - ΣΔH°f(reactants). Use the given ΔH°f values for N2O4(g) and NO2(g) to calculate ΔH° for the reaction.

Calculate the standard entropy change (ΔS°) for the reaction: ΔS° = ΣS°(products) - ΣS°(reactants). Use the given standard molar entropy for BrCl(g) and assume similar values for NO2(g) and N2O4(g) if not provided.

Substitute the calculated values of ΔG°, ΔH°, and ΔS° into the equation ΔG° = ΔH° - TΔS° to solve for ΔG° at 660 K. Then, use ΔG° = -RT ln(K) to solve for the equilibrium constant K at 660 K.