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Ch.15 - Chemical Equilibrium
Chapter 15, Problem 65

Consider this reaction at equilibrium: 2KClO3(s) ⇌ 2KCl(s) + 3O2(g). Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. a. O2 is removed from the reaction mixture. b. KCl is added to the reaction mixture. c. KClO3 is added to the reaction mixture. d. O2 is added to the reaction mixture.

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Identify the principle governing the reaction shifts: Le Chatelier's Principle, which states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change.
For part (a), removing O2 decreases the concentration of a product. According to Le Chatelier's Principle, the equilibrium will shift to the right to produce more O2.
For part (b), adding KCl increases the concentration of a product. According to Le Chatelier's Principle, the equilibrium will shift to the left to reduce the concentration of KCl.
For part (c), adding KClO3 increases the concentration of a reactant. Since KClO3 is a solid, its concentration does not affect the equilibrium position, so the equilibrium remains unchanged.
For part (d), adding O2 increases the concentration of a product. According to Le Chatelier's Principle, the equilibrium will shift to the left to reduce the concentration of O2.

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. This means that if a reactant or product concentration is altered, the system will adjust to restore equilibrium, either by favoring the forward or reverse reaction.
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Le Chatelier's Principle

Equilibrium Constant (K)

The equilibrium constant (K) quantifies the ratio of the concentrations of products to reactants at equilibrium for a given reaction at a specific temperature. Changes in concentration, pressure, or temperature can affect the value of K, influencing the direction in which the reaction will shift to re-establish equilibrium.
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Equilibrium Constant K

Reaction Quotient (Q)

The reaction quotient (Q) is a measure of the relative concentrations of products and reactants at any point in time, not just at equilibrium. By comparing Q to K, one can predict the direction in which the reaction will shift: if Q < K, the reaction shifts right to produce more products; if Q > K, it shifts left to produce more reactants.
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Related Practice
Textbook Question

Consider this reaction at equilibrium: 2 BrNO(g) ⇌ 2 NO(g) + Br2(g) Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. a. NO is added to the reaction mixture.

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Textbook Question

Consider this reaction at equilibrium: 2 BrNO(g) ⇌ 2 NO(g) + Br2(g) Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. b. BrNO is added to the reaction mixture.

773
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Textbook Question

Consider this reaction at equilibrium: 2 BrNO(g) ⇌ 2 NO(g) + Br2(g) Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. c. Br2 is removed from the reaction mixture.

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Textbook Question

Consider this reaction at equilibrium: C(s) + H2O(g) ⇌ CO(g) + H2(g) Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. a. C is added to the reaction mixture. b. H2O is condensed and removed from the reaction mixture. Predict whether the reaction will shift left, shift right, or remain unchanged after each disturbance. c. CO is added to the reaction mixture. d. H2 is removed from the reaction mixture.

5795
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Textbook Question

Each reaction is allowed to come to equilibrium, and then the volume is changed as indicated. Predict the effect (shift right, shift left, or no effect) of the indicated volume change. a. I2( g) ⇌ 2 I( g) (volume is increased) b. 2 H2S( g) ⇌ 2 H2( g) + S2(g) (volume is decreased) c. I2(g) + Cl2(g) ⇌ 2 ICl(g) (volume is decreased)

1210
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Textbook Question

Each reaction is allowed to come to equilibrium, and then the volume is changed as indicated. Predict the effect (shift right, shift left, or no effect) of the indicated volume change. a. CO(g) + H2O( g) ⇌ CO2(g) + H2(g) (volume is decreased)

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