Domanda del libro di testo
Tell whether the free-energy changes, ΔG, for the processes listed in Problem 9.127 are likely to be positive, negative, or zero.
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Ch.9 - Thermochemistry: Chemical Energy
McMurry8th EditionChemistryISBN: 9781292336145
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TOC.tableOfContents
- Ch.1 - Chemical Tools: Experimentation & Measurement170
- Ch.2 - Atoms, Molecules & Ions160
- Ch.3 - Mass Relationships in Chemical Reactions169
- Ch.4 - Reactions in Aqueous Solution199
- Ch.5 - Periodicity & Electronic Structure of Atoms102
- Ch.6 - Ionic Compounds: Periodic Trends and Bonding Theory92
- Ch.7 - Covalent Bonding and Electron-Dot Structures61
- Ch.8 - Covalent Compounds: Bonding Theories and Molecular Structure59
- Ch.9 - Thermochemistry: Chemical Energy122
- Ch.10 - Gases: Their Properties & Behavior155
- Ch.11 - Liquids & Phase Changes54
- Ch.12 - Solids and Solid-State Materials73
- Ch.13 - Solutions & Their Properties120
- Ch.14 - Chemical Kinetics98
- Ch.15 - Chemical Equilibrium125
- Ch.16 - Aqueous Equilibria: Acids & Bases110
- Ch.17 - Applications of Aqueous Equilibria147
- Ch.18 - Thermodynamics: Entropy, Free Energy & Equilibrium86
- Ch.19 - Electrochemistry154
- Ch.20 - Nuclear Chemistry96
- Ch.21 - Transition Elements and Coordination Chemistry156
- Ch.22 - The Main Group Elements187
- Ch.23 - Organic and Biological Chemistry51
Capitolo 9, Problema 123
What are the two terms that make up the free-energy change for a reaction, ΔG, and which of the two is usually more important?
Guida verificata passo dopo passo1
Step 1: Understand that the free-energy change for a reaction, denoted as ΔG, is a thermodynamic quantity that predicts the direction of a chemical reaction and its spontaneity.
Step 2: Recognize that ΔG is composed of two main terms: the enthalpy change (ΔH) and the entropy change (ΔS), which are related by the equation ΔG = ΔH - TΔS, where T is the temperature in Kelvin.
Step 3: The enthalpy change (ΔH) represents the heat absorbed or released during a reaction at constant pressure. It indicates whether a reaction is exothermic (releases heat) or endothermic (absorbs heat).
Step 4: The entropy change (ΔS) measures the change in disorder or randomness of the system. A positive ΔS indicates an increase in disorder, while a negative ΔS indicates a decrease.
Step 5: Consider that the relative importance of ΔH and TΔS depends on the specific reaction and conditions, but generally, at lower temperatures, ΔH tends to be more significant, while at higher temperatures, TΔS can become more influential.
Concetti chiave
Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.
Gibbs Free Energy (ΔG)
Gibbs Free Energy (ΔG) is a thermodynamic potential that measures the maximum reversible work obtainable from a thermodynamic system at constant temperature and pressure. It is a crucial indicator of the spontaneity of a reaction; a negative ΔG suggests that a reaction can occur spontaneously, while a positive ΔG indicates non-spontaneity.
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01:51
Gibbs Free Energy of Reactions
Enthalpy (ΔH)
Enthalpy (ΔH) is a measure of the total heat content of a system. It reflects the energy required to break and form bonds during a chemical reaction. In the context of Gibbs Free Energy, ΔH contributes to the overall energy change, influencing whether a reaction is exothermic or endothermic, which can affect the spontaneity of the reaction.
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02:34Enthalpy of Formation
Entropy (ΔS)
Entropy (ΔS) is a measure of the disorder or randomness in a system. In thermodynamics, it plays a critical role in determining the spontaneity of a reaction. Generally, an increase in entropy (positive ΔS) favors spontaneity, and in many cases, the contribution of entropy to ΔG is considered more significant than that of enthalpy, especially at higher temperatures.
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02:46Entropy in Thermodynamics
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