16. Chemical Equilibrium

Intro to Chemical Equilibrium

Multiple Choice
Cyclohexane, C6H12, undergoes a molecular rearrangement in the presence of AlCl3 to form methylcyclopentane, CH3C5H9, according to the equation: C6H12 ⇌ CH3C5H9. If Kc = 0.143 at 25°C for this reaction, what is the equilibrium concentration ratio of CH3C5H9 to C6H12?
Multiple Choice
The following two isomers of C3H7NO exist in equilibrium with each other in solution: If K_c = 0.57 at 25°C and the initial concentration of the reactant is 0.50 M and the product is 0.70 M, what are the concentrations of the reactant and product at equilibrium?
Multiple Choice
The following picture represents the equilibrium state for the reaction A2 + B2 ⇌ 2AB (A = white; B = gray). What is the relationship between the rate constant for the forward reaction, kf, and the rate constant for the reverse reaction kr at equilibrium?
Multiple Choice
Which one of the following statements does not describe the equilibrium state?
a. While at equilibrium, a dynamic process is still occurring.
b. The concentration of the reactants is equal to the concentration of the products.
c. The concentration of the reactants and products reach a constant level.
d. At equilibrium, the net concentration of all species is not changing.
e. All are true.
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Multiple Choice
Given the following reaction at equilibrium at 450.0 °C: CaCO3 (s) ⇌ CaO (s) + CO2 (g). If pCO2 = 0.0160 atm, what is the Kc value?
Multiple Choice
Gaseous hydrogen bromide decomposes at elevated temperatures according to the following equation: 2 HBr(g) ⇌ H2(g) + Br2(g). At a certain temperature, a 2.00 L flask is initially filled only with 0.600 mol of HBr. If the equilibrium concentration of H2 is 0.100 M, what is the value of Kc at that temperature?
Multiple Choice
Which of the following statements about the equilibrium constant (K) is true?
Multiple Choice
Given the hypothetical reaction 2 A (s) + ? B (g) ⇌ 3 C (g), Kp = 0.0105 and Kc = 0.45 at 250 degrees Celsius. What is the value of the coefficient of B?
Multiple Choice
In which of the given reactants is K_p greater than, less than and equal to K_c?
a) SO₃ (g) + NO (g) ⇌ SO₂ (g) + NO₂ (g)
b) P₄ (s) + 5 O₄ (g) ⇌ P₄O₁₀ (s)
c) 4 NH₃ (g) + 3 O₂ (g) ⇌ 2 N₂ (g) + 6 H₂O (g)
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Multiple Choice
The equilibrium constant, Kp, equals 3.40 at 25°C for the isomerization reaction: cis-2-butene ⇌ trans-2-butene. If a flask initially contains 1.00 atm of each gas, in what direction will the system shift to reach equilibrium?
Multiple Choice
State which is greater in amount:reactants or products, based on the given equilibrium constant, K.
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Open Question
Which statement correctly describes a reaction in dynamic equilibrium? At dynamic equilibrium, the reactions stop and the amounts of reactants and products do not change. At dynamic equilibrium, the reactions continue but the amounts of reactants and products do not change. At dynamic equilibrium, the reactions stop but the amounts of reactants and products are changing. At dynamic equilibrium, the reactions continue and the amounts of reactants and products are changing.
Multiple Choice
In the reaction C(s) + CO2(g) ⇌ 2CO(g), if the initial pressure of CO2 is 0.800 atm and the equilibrium pressure of CO is 1.10 atm, what is the equilibrium pressure of CO2?
Multiple Choice
Which of the following does not represent a heterogenous equilibrium?
I) CH₄(g) + 2 O₂(g) ⇌ CO₂(g) + 2 H₂O(g)
II) CO₂(g) + C(s) ⇌ 2 CO(g)
III) 2 H₂O(l) ⇌ 2 H₂(g) + O₂(g)
IV) CH₃COOH(aq) + H₂O(l) ⇌ CH₃COO^–(aq) + H₃O⁺(aq)
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Multiple Choice
A chemical system is said to have reached the state of equilibrium when: