Name: Chemistry: The Central Science
Author: Brown
ISBN: 9780134414232

Ch.15 - Chemical Equilibrium

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모든 교과서

Brown 14th Edition

Ch.15 - Chemical Equilibrium

문제 1a

(a) Based on the following energy profile, predict whether k_f > k_r or k_f < k_r. [Section 15.1]

문제 2

The following diagrams represent a hypothetical reaction A ¡ B, with A represented by red spheres and B represented by blue spheres. The sequence from left to right represents the system as time passes. Does the system reach equilibrium? If so, in which diagram(s) is the system in equilibrium? [Sections 15.1 and 15.2]

문제 3

Consider the equilibrium Na2O(s) + SO2(g) ⇌ Na2SO3(s). (a) Write the equilibrium-constant expression for this reaction in terms of partial pressures. (b) All the compounds in this reaction are soluble in water. Rewrite the equilibrium-constant expression in terms of molarities for the aqueous reaction.

문제 4

A chemist at a pharmaceutical company is measuring equilibrium constants for reactions in which drug candidate molecules bind to a protein involved in cancer. The drug molecules bind the protein in a 1:1 ratio to form a drug–protein complex. The protein concentration in aqueous solution at 25 _x001F_C is 1.50 * 10^-6 M. Drug A is introduced into the protein solution at an initial concentration of 2.00 * 10^-6 M. Drug B is introduced into a separate, identical protein solution at an initial concentration of 2.00 * 10^-6 M. At equilibrium, the drug A–protein solution has an A–protein complex concentration of 1.00 * 10^-6 M, and the drug B solution has a B–protein complex concentration of 1.40 * 10^-6 M. Calculate the Kc value for the A–protein binding reaction and for the B–protein binding reaction. Assuming that the drug that binds more strongly will be more effective, which drug is the better choice for further research?

문제 4d

The following diagram represents a reaction shown going to completion. Each molecule in the diagram represents 0.1 mol, and the volume of the box is 1.0 L. (d) Assuming that all of the molecules are in the gas phase, calculate n, the change in the number of gas molecules that accompanies the reaction. [Section 15.2]

문제 6

Ethene (C₂H₄) reacts with halogens (X₂) by the following reaction:

C₂H₄(𝑔) + X₂(𝑔) ⇌ C₂H₄X₂(𝑔)

The following figures represent the concentrations at equilibrium at the same temperature when X₂ is Cl₂ (green), Br₂ (brown), and I₂ (purple). List the equilibria from smallest to largest equilibrium constant. [Section 15.3]

문제 7

True or false: When the temperature of an exothermic reaction increases, the rate constant of the forward reaction decreases, which leads to a decrease in the equilibrium constant, Kc.

문제 7a

When lead(IV) oxide is heated above 300°C, it decomposes according to the reaction, 2 PbO2(𝑠) ⇌ 2PbO(𝑠) + O2(𝑔). Consider the two sealed vessels of PbO2 shown here. If both vessels are heated to 400°C and allowed to come to equilibrium, which of the following statements is or are true? a. There will be less PbO₂remaining in vessel A,

문제 7b

When lead(IV) oxide is heated above 300°C, it decomposes according to the reaction, 2 PbO₂(𝑠)⇌2PbO(𝑠)+O2(𝑔). Consider the two sealed vessels of PbO₂ shown here. If both vessels are heated to 400°C and allowed to come to equilibrium, which of the following statements is or are true?

b. There will be less PbO₂ remaining in vessel B,

문제 7c

When lead(IV) oxide is heated above 300°C, it decomposes according to the reaction, 2 PbO₂(𝑠) ⇌ 2PbO(𝑠) + O₂(𝑔). Consider the two sealed vessels of PbO₂ shown here. If both vessels are heated to 400°C and allowed to come to equilibrium, which of the following statements is or are true? (c) The amount of PbO₂ remaining in each vessel will be the same. [Find more in Section 15.4]

문제 8a

The reaction A₂ + B₂ ⇌ 2 AB has an equilibrium constant K_c = 1.5. The following diagrams represent reaction mixtures containing A₂ molecules (red), B₂ molecules (blue), and AB molecules. (a) Which reaction mixture is at equilibrium?

문제 9

The reaction PCl₃(g) + Cl₂(g) ⇌ PCl₅(g) has Kp = 0.0870 at 300 _x001F_C. A flask is charged with 0.50 atm PCl₃, 0.50 atm Cl₂, and 0.20 atm PCl₅ at this temperature. (d) The reaction is exothermic. What effect will increasing the temperature of the system have on the mole fraction of Cl₂ in the equilibrium mixture?

문제 10a

The diagram shown here represents the equilibrium state for the reaction A2(𝑔) + 2B(𝑔) ⇌ 2AB(𝑔). (a) Assuming the volume is 2 L, calculate the equilibrium constant 𝐾𝑐 for the reaction.

문제 13

Suppose that the gas-phase reactions A → B and B → A are both elementary reactions with rate constants of 4.7×10⁻³ s⁻¹ and 5.8×10⁻¹ s⁻¹, respectively. (a) What is the value of the equilibrium constant for the equilibrium A(g) ⇌ B(g)? (b) Which is greater at equilibrium, the partial pressure of A or the partial pressure of B?

문제 14a

The equilibrium constant for the dissociation of molecular iodine, I₂(g) ⇌ 2 I(g), at 800 K is K_c = 3.1 × 10^–5. (a) Which species predominates at equilibrium I₂ or I?

문제 14b

The equilibrium constant for the dissociation of molecular iodine, I₂(g) ⇌ 2 I(g), at 800 K is K_c= 3.1×10⁻⁵. (b) Assuming both forward and reverse reactions are elementary reactions, which reaction has the larger rate constant, the forward or the reverse reaction?

문제 15e

Write the expression for K_c for the following reactions. In each case indicate whether the reaction is homogeneous or heterogeneous.

(a) 3 NO(g) ⇌ N₂O(g) + NO₂(g)

(b) CH₄(g) + 2 H₂S(g) ⇌ CS2(g) + 4 H₂(g)

(d) HF(aq) ⇌ H⁺(aq) + F^-(aq)

(e) 2Ag(s) + Zn²⁺(aq) ⇌ 2 Ag⁺(aq) + Zn(s)

(f) H₂O(l) ⇌ H⁺(aq) + OH^-(aq)

(g) 2 H₂O(l) ⇌ 2 H⁺(aq) + 2 OH^-(aq)

문제 16a,c,d,e,f,g

Write the expressions for K_c for the following reactions. In each case indicate whether the reaction is homogeneous or heterogeneous.

(a) 2 O₃(g) ⇌ 3 O₂(g)

(d) C(s) + 2 H₂(g) ⇌ CH₄(g)

(e) 4 HCl(aq) + O₂(g) ⇌ 2 H₂O(l) + 2 Cl₂(g)

(f) 2 C₈H₁₈(l) + 25 O₂(g) ⇌ 16 CO₂(g) + 18 H₂O(g)

(g) 2 C₈H₁₈(l) + 25 O₂(g) ⇌ 16 CO₂(g) + 18 H₂O(l)

문제 16b

Write the expressions for 𝐾_𝑐 for the following reactions. In each case indicate whether the reaction is homogeneous or heterogeneous.

(b) Ti(𝑠) + 2Cl₂(𝑔) ⇌ TiCl₄(𝑙)

문제 17

When the following reactions come to equilibrium, does the equilibrium mixture contain mostly reactants or mostly products? (a) N2(g) + O2(g) ⇌ 2 NO(g), Kc = 1.5 × 10^-10 (b) 2 SO2(g) + O2(g) ⇌ 2 SO3(g), Kp = 2.5 × 10^9

문제 18

Which of the following reactions lies to the right, favoring the formation of products, and which lies to the left, favoring the formation of reactants?

(a) 2 NO(g) + O₂(g) ⇌ 2 NO₂(g) Kp = 5.0 × 10¹²

(b) 2 HBr(g) ⇌ H₂(g) + Br₂(g) K_c= 5.8×10⁻¹⁸

문제 19

Which of the following statements are true and which are false? (a) The equilibrium constant can never be a negative number. (b) In reactions that we draw with a single-headed arrow, the equilibrium constant has a value that is very close to zero.

문제 19a,b

문제 19c

Which of the following statements are true and which are false? (c) As the value of the equilibrium constant increases, the speed at which a reaction reaches equilibrium must increase.

문제 21

If 𝐾_𝑐= 0.042 for PCl₃(𝑔) + Cl₂(𝑔) ⇌ PCl₅(𝑔) at 500 K, what is the value of 𝐾_𝑝 for this reaction at this temperature?

문제 22

Calculate Kc at 303 K for SO2(g) + Cl2(g) ⇌ SO2Cl2(g) if Kp = 34.5 at this temperature.

문제 23

The equilibrium constant for the reaction 2 NO(g) + Br2(g) ⇌ 2 NOBr(g) is Kc = 1.3 * 10^-2 at 1000 K. (b) Calculate Kc for 2 NOBr(g) ⇌ 2 NO(g) + Br2(g). (c) Calculate Kc for NOBr(g) ⇌ NO(g) + 1/2 Br2(g).

문제 24b

Consider the following equilibrium: 2 H₂(g) + S₂(g) ⇌ 2 H₂S(g) K_c = 1.08 × 10⁷ at 700°C (b) Does the equilibrium mixture contain mostly H₂ and S₂ or mostly H₂S?

문제 24c

Consider the following equilibrium: 2 H₂(g) + S₂(g) ⇌ 2 H₂S(g) K_c = 1.08 × 10⁷ at 700°C (c) Calculate the value of 𝐾𝑐 if you rewrote the equation H₂(g) + 1/2 S₂(g) ⇌ H₂S(g)

문제 25

At 1000 K, Kp = 1.85 for the reaction SO2(g) + 1/2 O2(g) ⇌ SO3(g). (a) What is the value of Kp for the reaction SO3(g) ⇌ SO2(g) + 1/2 O2(g)? (b) What is the value of Kp for the reaction 2 SO2(g) + O2(g) ⇌ 2 SO3(g)?