Textbook Question
Consider the gas-phase reaction of AB3 and A2 molecules: (a) Write a balanced equation for the reaction.(b) What is the sign of the entropy change for the reaction?
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Ch.18 - Thermodynamics: Entropy, Free Energy & Equilibrium
McMurry8th EditionChemistryISBN: 9781292336145
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Table of contents
- Ch.1 - Chemical Tools: Experimentation & Measurement143
- Ch.2 - Atoms, Molecules & Ions134
- Ch.3 - Mass Relationships in Chemical Reactions149
- Ch.4 - Reactions in Aqueous Solution157
- Ch.5 - Periodicity & Electronic Structure of Atoms92
- Ch.6 - Ionic Compounds: Periodic Trends and Bonding Theory73
- Ch.7 - Covalent Bonding and Electron-Dot Structures47
- Ch.8 - Covalent Compounds: Bonding Theories and Molecular Structure51
- Ch.9 - Thermochemistry: Chemical Energy104
- Ch.10 - Gases: Their Properties & Behavior138
- Ch.11 - Liquids & Phase Changes43
- Ch.12 - Solids and Solid-State Materials56
- Ch.13 - Solutions & Their Properties98
- Ch.14 - Chemical Kinetics79
- Ch.15 - Chemical Equilibrium107
- Ch.16 - Aqueous Equilibria: Acids & Bases94
- Ch.17 - Applications of Aqueous Equilibria125
- Ch.18 - Thermodynamics: Entropy, Free Energy & Equilibrium66
- Ch.19 - Electrochemistry130
- Ch.20 - Nuclear Chemistry73
- Ch.21 - Transition Elements and Coordination Chemistry122
- Ch.22 - The Main Group Elements155
- Ch.23 - Organic and Biological Chemistry43
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McMurry 8th EditionCh.18 - Thermodynamics: Entropy, Free Energy & EquilibriumProblem 27c
McMurry 8th EditionCh.18 - Thermodynamics: Entropy, Free Energy & EquilibriumProblem 27cChapter 18, Problem 27c
Ideal gases A (red spheres) and B (blue spheres) occupy two separate bulbs. The contents of both bulbs constitute the initial state of an isolated system. Consider the process that occurs when the stopcock is opened.
(c) How dpes this process illustrate the second law of thermodynamics?
Verified step by step guidance1
Identify the initial state: Two separate bulbs contain ideal gases A (red spheres) and B (blue spheres), separated by a stopcock.
Understand the process: When the stopcock is opened, gases A and B will mix and occupy the combined volume of both bulbs.
Recall the second law of thermodynamics: It states that the total entropy of an isolated system can never decrease over time; it can only increase or remain constant.
Analyze the entropy change: The mixing of gases A and B increases the randomness and disorder of the system, leading to an increase in entropy.
Conclude the illustration: This process demonstrates the second law of thermodynamics as the entropy of the system increases when the gases mix, moving towards a state of higher disorder.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Second Law of Thermodynamics
The Second Law of Thermodynamics states that in any energy transfer or transformation, the total entropy of an isolated system can never decrease over time. This means that natural processes tend to move towards a state of greater disorder or randomness. In the context of the question, when the stopcock is opened, the gases A and B will mix, leading to an increase in entropy as the system transitions from a more ordered state (separate gases) to a more disordered state (mixed gases).
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Second Law of Thermodynamics Example
Entropy
Entropy is a measure of the amount of disorder or randomness in a system. It quantifies the number of ways a system can be arranged while still maintaining the same energy level. In the scenario presented, the initial state has lower entropy due to the separation of gases, while the final state after opening the stopcock has higher entropy as the gases mix, illustrating the natural tendency towards increased disorder.
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Isolated System
An isolated system is one that does not exchange matter or energy with its surroundings. In the context of the question, the two bulbs containing gases A and B represent an isolated system where the only interaction occurs when the stopcock is opened. This concept is crucial for understanding how the gases behave and how the entropy changes, as the system's isolation ensures that the total energy remains constant while the entropy increases.
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Related Practice
Textbook Question
Consider the dissociation reaction A2(g) ⇌ 2 A(g). The following pictures represent two possible initial states and the equilibrium state of the system:
(b) What are the signs ( + , - , or 0) of ∆H, ∆S, and ∆G when the system goes from initial state 1 to the equilibrium state? Explain. Is this a spontaneous process?
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Textbook Question
Ideal gases A (red spheres) and B (blue spheres) occupy two separate bulbs. The contents of both bulbs constitute the initial state of an isolated system. Consider the process that occurs when the stopcock is opened.
(b) What are the signs ( + , - , or 0) of ∆H, ∆S, and ∆G for this process? Explain.
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Textbook Question
Ideal gases A (red spheres) and B (blue spheres) occupy two separate bulbs. The contents of both bulbs constitute the initial state of an isolated system. Consider the process that occurs when the stopcock is opened.
(a) Sketch the final (equilibrium) state of the system.
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Textbook Question
Rank the situations represented by the following drawings according to increasing entropy.
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Textbook Question
The following pictures represent equilibrium mixtures for the interconversion of A molecules (red) and X, Y, or Z molecules (blue): What is the sign of ∆G° for each of the three reactions?
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