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 Calculations

General Chemistry

19. Chemical Thermodynamics

Gibbs Free Energy Calculations

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Multiple Choice

Calculate and report ΔrG°T for the dissolution of Ca(OH)2(s) in water at 25°C, given that ΔH° = -985.2 kJ/mol and ΔS° = -0.353 kJ/mol·K.

-879.9 kJ/mol

-990.1 kJ/mol

-987.5 kJ/mol

-882.3 kJ/mol

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Verified step by step guidance

Understand the relationship between Gibbs free energy change (ΔrG°), enthalpy change (ΔH°), and entropy change (ΔS°) using the equation: ΔrG° = ΔH° - TΔS°. This equation helps us determine the spontaneity of a reaction at a given temperature.

Identify the given values: ΔH° = -985.2 kJ/mol, ΔS° = -0.353 kJ/mol·K, and the temperature T = 25°C. Convert the temperature to Kelvin by adding 273.15 to the Celsius temperature: T = 25 + 273.15 = 298.15 K.

Substitute the values into the Gibbs free energy equation: ΔrG° = ΔH° - TΔS°. Ensure that the units are consistent. Here, both ΔH° and ΔS° are in kJ, so no conversion is needed.

Calculate the term TΔS° by multiplying the temperature in Kelvin (298.15 K) by the entropy change (ΔS° = -0.353 kJ/mol·K): TΔS° = 298.15 K * (-0.353 kJ/mol·K).

Substitute the calculated TΔS° value back into the Gibbs free energy equation: ΔrG° = -985.2 kJ/mol - TΔS°. Perform the subtraction to find the Gibbs free energy change for the dissolution of Ca(OH)2(s) in water at 25°C.