Textbook Question
For the following values of ∆H° , ∆S°, and T, tell whether the process would be favored.
(b) ∆H° = +7.34 kcal/mol ; ∆S° = +43 cal/mol•K ; T = 325 K
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Ch. 5 - Chemical Reaction Analysis: Thermodynamics and Kinetics
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471
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Table of contents
- Ch. 2 - General Chemistry Translated: Finding the Electrons114
- Ch. 3 - Alkanes and Cycloalkanes: Properties and Conformational Analysis109
- Ch. 4 - Acids and Bases: Electron Flow144
- Ch. 5 - Chemical Reaction Analysis: Thermodynamics and Kinetics118
- Ch. 6 - Stereoisomerism: Arrangement of Atoms in Space112
- Ch. 7 - Principles of Green (Organic) Chemistry3
- Ch. 8 - Alkenes I: Properties and Electrophilic Additions158
- Ch. 9 - Alkenes II: Oxidation and Reduction150
- Ch. 10 - Alkynes: Electrophilic Addition and Redox Reactions101
- Ch. 11 - Properties and Synthesis of Alkyl Halides: Radical Reactions108
- Ch. 12 - Substitution and Elimination: Reactions of Haloalkanes172
- Ch. 13 - Alcohols, Ethers and Related Compounds: Substitution and Elimination239
- Ch. 14 - Structural Identification I: Infrared Spectroscopy and Mass Spectrometry54
- Ch. 15 - Structural Identification II: Nuclear Magnetic Resonance Spectroscopy93
- Ch. 16 - Metals in Organic Chemistry48
- Ch. 17 - Carbonyl Addition Reactions: Aldehydes and Ketones45
- Ch. 18 - Nucleophilic Acyl Substitution I: Carboxylic Acids18
- Ch. 19 - Nucleophilic Acyl Substitution II: Carboxylic Acid Derivatives39
- Ch. 20 - Enolates: Carbonyl Addition and Substitution13
- Ch. 21 - Conjugated Systems I: Stability and Addition Reactions56
- Ch. 22 - Conjugated Systems II: Pericyclic Reactions54
- Ch. 23 - Benzene I: Aromatic Stability and Substitution Reactions64
- Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring62
- Ch. 25 - Amines: Structure, Reactions, and Synthesis27
- Ch. 26 - Amino Acids, Proteins, and Peptide Synthesis9
- Ch. 27 - Carbohydrates, Nucleic Acids, and Lipids54
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
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Mullins 1st EditionCh. 5 - Chemical Reaction Analysis: Thermodynamics and KineticsProblem 11a
Mullins 1st EditionCh. 5 - Chemical Reaction Analysis: Thermodynamics and KineticsProblem 11aChapter 4, Problem 11a
For the following values of ∆H° , ∆S°, and T, tell whether the process would be favored.
(a) ∆H° = -15 kcal/mol ; ∆S° = +37 cal/mol•K ; T = 273 K
Verified step by step guidance1
Step 1: Recall the Gibbs free energy equation: . This equation determines whether a process is thermodynamically favored. A negative value for indicates a favored process.
Step 2: Convert the units of to match the units of . Since is given in kcal/mol and is in cal/mol•K, divide by 1000 to convert it to kcal/mol•K.
Step 3: Substitute the given values into the Gibbs free energy equation. Use kcal/mol, kcal/mol•K, and K.
Step 4: Calculate the term by multiplying the temperature by . This will give the contribution of entropy to the Gibbs free energy.
Step 5: Determine the sign of by subtracting from . If is negative, the process is thermodynamically favored; if positive, it is not favored.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Gibbs Free Energy
Gibbs Free Energy (G) is a thermodynamic potential that helps predict whether a process will occur spontaneously at constant temperature and pressure. It is calculated using the equation ΔG = ΔH - TΔS, where ΔH is the change in enthalpy, T is the temperature in Kelvin, and ΔS is the change in entropy. A negative ΔG indicates that the process is favored.
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05:02
Breaking down the different terms of the Gibbs Free Energy equation.
Enthalpy (ΔH)
Enthalpy (ΔH) is a measure of the total heat content of a system. A negative ΔH value, such as -15 kcal/mol, indicates that the process is exothermic, meaning it releases heat. This release of energy generally favors the spontaneity of a reaction, contributing to a negative ΔG when combined with the entropy term.
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04:38Calculating Enthalpies
Entropy (ΔS)
Entropy (ΔS) is a measure of the disorder or randomness in a system. A positive ΔS value, like +37 cal/mol•K, suggests that the process increases the disorder of the system, which is favorable for spontaneity. In the Gibbs Free Energy equation, a higher entropy contributes to a more negative ΔG, especially at higher temperatures.
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02:46Explaining what entropy is.
Related Practice
Textbook Question
For the following equilibrium processes and the corresponding ∆G°, calculate (i) Keq and (ii) the % composition of the equilibrium mixture (% reactants, % products) at 298 K.
(b)
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Textbook Question
For the following equilibrium processes and the corresponding ∆G°, calculate (i) Keq and (ii) the % composition of the equilibrium mixture (% reactants, % products) at 298 K.
(a)
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Textbook Question
For the following values of ∆H° , ∆S°, and T, tell whether the process would be favored.
(c) ∆H° = -21.3 kcal/mol ; AS° = -51 cal/mol•K ; T = 373 K
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Textbook Question
For the following values of ∆H° , ∆S°, and T, tell whether the process would be favored.
(d) ∆H° = -8.3 kcal/mol ; ∆S° = -12 cal/mol•K ; T = 298 K
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Textbook Question
For the following equilibrium processes and the corresponding ∆G° , indicate whether you expect the equilibrium constant to be greater than, equal to, or less than 1. Justify your expectation in words.
(b)
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