Textbook Question
When the following equilibria are disturbed by increasing the pressure, does the concentration of reaction products increase, decrease, or remain the same?
a. 2 CO2(g) ⇌ 2 CO(g) + O2(g)
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Ch.7 Chemical Reactions: Energy, Rate and Equilibrium
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187
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Table of contents
- Ch.1 Matter and Measurements27
- Ch.2 Atoms and the Periodic Table20
- Ch.3 Ionic Compounds8
- Ch.4 Molecular Compounds23
- Ch.5 Classification & Balancing of Chemical Reactions12
- Ch.6 Chemical Reactions: Mole and Mass Relationships28
- Ch.7 Chemical Reactions: Energy, Rate and Equilibrium64
- Ch.8 Gases, Liquids and Solids24
- Ch.9 Solutions52
- Ch.10 Acids and Bases25
- Ch.11 Nuclear Chemistry22
- Ch.12 Introduction to Organic Chemistry: Alkanes57
- Ch.13 Alkenes, Alkynes, and Aromatic Compounds47
- Ch.14 Some Compounds with Oxygen, Sulfur, or a Halogen50
- Ch.15 Aldehydes and Ketones45
- Ch.16 Amines42
- Ch.17 Carboxylic Acids and Their Derivatives57
- Ch.18 Amino Acids and Proteins82
- Ch.19 Enzymes and Vitamins63
- Ch.20 Carbohydrates44
- Ch.21 The Generation of Biochemical Energy65
- Ch.22 Carbohydrate Metabolism45
- Ch.23 Lipids42
- Ch.24 Lipid Metabolism33
- Ch.25 Protein and Amino Acid Metabolism24
- Ch.26 Nucleic Acids and Protein Synthesis45
McMurry8th EditionFundamentals of General, Organic, and Biological ChemistryISBN: 9780134015187Not the one you use?Change textbook
Chapter 7, Problem 63
The reaction CO(g) + H2O(g) ⇌ CO2(g) + H2(g) has ∆H = -9.8 kcal/mol (-41 kJ/mol). Does the amount of H2 in an equilibrium mixture increase or decrease when the temperature is decreased?
Verified step by step guidance1
Identify the type of reaction based on the given enthalpy change (∆H). Since ∆H = -9.8 kcal/mol, the reaction is exothermic, meaning it releases heat as a product.
Recall Le Châtelier's Principle, which states that if a system at equilibrium is subjected to a change in temperature, pressure, or concentration, the system will adjust to counteract that change and restore equilibrium.
Understand the effect of temperature on an exothermic reaction. Decreasing the temperature removes heat from the system. According to Le Châtelier's Principle, the equilibrium will shift to produce more heat, favoring the exothermic (forward) reaction.
Analyze the forward reaction: CO(g) + H2O(g) ⇌ CO2(g) + H2(g). Since the forward reaction produces H2 as a product, a shift toward the forward reaction will increase the amount of H2 in the equilibrium mixture.
Conclude that when the temperature is decreased, the equilibrium shifts toward the forward reaction, resulting in an increase in the amount of H2 in the equilibrium mixture.
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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 system will adjust to counteract the change and restore a new equilibrium. In the context of temperature changes, if the temperature is decreased, the equilibrium will shift in the direction that produces heat, which can affect the concentrations of reactants and products.
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09:34
The following is an endothermic reaction where Kc = 6.73 x 103.For each of the choices below predict in which direction the reaction will proceed
Exothermic Reactions
An exothermic reaction is one that releases heat, indicated by a negative enthalpy change (∆H). In this reaction, since ∆H = -9.8 kcal/mol, it means that heat is released when CO and H2O react to form CO2 and H2. Lowering the temperature favors the formation of products in exothermic reactions, as the system seeks to produce more heat.
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Equilibrium Constant (K)
The equilibrium constant (K) is a numerical value that expresses the ratio of the concentrations of products to reactants at equilibrium for a given reaction at a specific temperature. Changes in temperature can alter the value of K, influencing the position of equilibrium. For exothermic reactions, a decrease in temperature typically increases K, favoring the formation of products, including H2.
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Related Practice
Textbook Question
The reaction H2(g) + I2(g) ⇌ 2 HI(g) has ∆H = -2.2 kcal/mol (-9.2 kJ/mol). Will the equilibrium concentration of HI increase or decrease when
c. A catalyst is added?
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Textbook Question
Hydrogen chloride can be made from the reaction of chlorine and hydrogen:
Cl2(g) + H2(g) → 2 HCl(g)
For this reaction, K = 26 × 1033 and ∆H = -44 kcal/mol(-184 kJ/mol) at 25 °C.
a. Is the reaction endothermic or exothermic?
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Textbook Question
For the following equilibria, use Le Châtelier's principle to predict the direction of the reaction when the pressure is increased by decreasing the volume of the equilibrium mixture.
a. C(s) + H2O(g) ⇌ CO(g) + H2(g)
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Textbook Question
The reaction Fe3+(aq) + Cl-(aq) ⇌ FeCl2+(aq) is endothermic. How will the equilibrium concentration of FeCl2+ change when
b. Cl- is precipitated by addition of AgNO3?
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Textbook Question
The reaction H2(g) + I2(g) ⇌ 2 HI(g) has ∆H = -2.2 kcal/mol (-9.2 kJ/mol). Will the equilibrium concentration of HI increase or decrease when
b. H2 is removed?
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