Textbook Question
The following pictures represent the composition of the equi- librium mixture for the reaction A + B ∆ AB at 300 K and at 400 K. Is the reaction exothermic or endothermic? Explain using Le Châtelier's principle.
Ch.15 - Chemical Equilibrium
McMurry8th EditionChemistryISBN: 9781292336145
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Table of contents
- 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
Chapter 15, Problem 48
The following picture represents the composition of the equi- librium mixture for the endothermic reaction A2 ∆ 2 A at 500 K. Draw a picture that represents the equilibrium mixture after each of the following changes.(b) Increasing the volume
Verified step by step guidance1
Identify the initial equilibrium mixture (image (i)) where the reaction A2 ⇌ 2A is at equilibrium.
Recognize that increasing the volume of the system will decrease the pressure.
According to Le Chatelier's principle, the system will shift to counteract this change by favoring the side with more gas molecules.
In this case, the reaction will shift towards the production of more A atoms (since 2A has more molecules than A2).
Draw the new equilibrium mixture (image (ii)) showing an increased number of A atoms and a decreased number of A2 molecules.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Le Chatelier's Principle
Le Chatelier's Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change. In the context of the reaction A2 ⇌ 2A, increasing the volume of the system will favor the side with more moles of gas, which in this case is the product side (2A), thus shifting the equilibrium to the right.
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07:32
Le Chatelier's Principle
Endothermic Reactions
An endothermic reaction is one that absorbs heat from its surroundings. In the reaction A2 ⇌ 2A, the forward reaction is endothermic, meaning that increasing the temperature will also favor the formation of products. Understanding this concept is crucial when predicting how changes in temperature and volume affect the equilibrium position.
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02:30Endothermic & Exothermic Reactions
Equilibrium Mixture
An equilibrium mixture refers to the state in a reversible reaction where the rates of the forward and reverse reactions are equal, resulting in constant concentrations of reactants and products. In the given reaction, the equilibrium mixture at 500 K consists of both A2 and A, and any changes in conditions, such as volume, will alter the concentrations of these species until a new equilibrium is established.
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02:38Equilibrium Constant Calculation
Related Practice
Textbook Question
Consider the reaction A + B ∆ AB. The vessel on the right contains an equilibrium mixture of A molecules (red spheres), B molecules (blue spheres), and AB molecules. If the stopcock is opened and the contents of the two vessels are allowed to mix, will the reaction go in the forward or reverse direction? Explain.
Textbook Question
The following pictures represent the initial and equilibrium states for the exothermic decomposition of gaseous A mol- ecules (red) to give gaseous B molecules (blue).(b) Will the number of A molecules in the equilibrium mix- ture increase, decrease, or remain the same after each of the following changes? Explain.(3) Increasing the pressure by adding an inert gas
Textbook Question
The following pictures represent the initial and equilibrium states for the exothermic decomposition of gaseous A mol- ecules (red) to give gaseous B molecules (blue). (a) Write a balanced chemical equation for the reaction.
Textbook Question
The following pictures represent the initial state and the equilibrium state for the reaction of A2 molecules (red) with B atoms (blue) to give AB molecules. (a) Write a balanced chemical equation for the reaction.
Textbook Question
The following picture represents the equilibrium state for the reaction 2 AB ∆ A2 + B2. Which rate constant is larger, kf or kr? Explain.