Textbook Question
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?
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Ch.7 Chemical Reactions: Energy, Rate and Equilibrium
McMurry8th EditionFundamentals of GOBISBN: 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
Chapter 7, Problem 66b
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?
Verified step by step guidance1
Identify the key components of the reaction: The reaction is Fe³⁺(aq) + Cl⁻(aq) ⇌ FeCl²⁺(aq), and it is endothermic. The equilibrium depends on the concentrations of Fe³⁺, Cl⁻, and FeCl²⁺.
Understand the effect of adding AgNO₃: Ag⁺ ions from AgNO₃ will react with Cl⁻ ions to form a precipitate of AgCl (Ag⁺(aq) + Cl⁻(aq) → AgCl(s)). This reduces the concentration of Cl⁻ in the solution.
Apply Le Châtelier's Principle: When the concentration of Cl⁻ decreases, the equilibrium will shift to counteract this change by producing more Cl⁻. This means the reaction will shift to the left (toward the reactants).
Determine the effect on FeCl²⁺: As the equilibrium shifts to the left, the concentration of FeCl²⁺ will decrease because it is being converted back into Fe³⁺ and Cl⁻.
Summarize the result: The equilibrium concentration of FeCl²⁺ will decrease when Cl⁻ is precipitated by the addition of AgNO₃.
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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 this case, adding AgNO3 causes Cl- ions to precipitate, which reduces their concentration in the solution. According to Le Chatelier's Principle, the equilibrium will shift to the right to produce more Cl- ions, thereby increasing the concentration of FeCl2+.
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. For the reaction Fe3+ + Cl- ⇌ FeCl2+, the equilibrium constant can help predict how changes in concentration will affect the system. If Cl- is removed from the solution, the equilibrium constant remains unchanged, but the concentrations of the species will adjust to restore equilibrium.
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Endothermic Reactions
An endothermic reaction is one that absorbs heat from its surroundings, resulting in a decrease in temperature of the environment. In the context of the given reaction, the endothermic nature implies that increasing temperature will favor the formation of products. However, in this scenario, the focus is on the concentration changes due to the precipitation of Cl-, which will influence the equilibrium position without directly altering the temperature.
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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
b. H2 is removed?
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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
c. A catalyst is added?
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Textbook Question
For the unbalanced combustion reaction shown, 1 mol of ethanol, C2H5OH, releases 327 kcal (1370 kJ):
C2H5OH + O2 → CO2 + H2O
e. If the density of ethanol is 0.789 g/mL, calculate the combustion energy of ethanol in kilocalories/milliliter and kilojoules/milliliter
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Textbook Question
For the production of ammonia from its elements, ∆H = -22 kcal/mol(-19 kJ/mol).
b. How much energy (in kilocalories and kilojoules) is involved in the production of 0.700 mol of NH3?
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Textbook Question
Magnetite, an iron ore with formula Fe3O4, can be reduced by treatment with hydrogen to yield iron metal and water vapor.
a. Write the balanced equation.
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