Textbook Question
The reaction 2 AsH31g2 ∆ As21g2 + 3 H21g2 has Kp =
7.2 * 107 at 1073 K. At the same temperature, what is Kp
for each of the following reactions?
(c) 9 H21g2 + 3 As21g2 ∆ 6 AsH31g2
Ch.15 - Chemical Equilibrium
Chapter 15, Problem 15.65
Calculate the value of the equilibrium constant for the reaction 4 NH31g2 + 3 O21g2 ∆ 2 N21g2 + 6 H2O1g2
given the following equilibrium constants at a certain temperature.
2 H21g2 + O21g2 ∆ 2 H2O1g2 Kc = 3.2 * 1081
N21g2 + 3 H21g2 ∆ 2 NH31g2 Kc = 3.5 * 108
Verified step by step guidance1
Identify the given reactions and their equilibrium constants. The first reaction is 2 H2(g) + O2(g) ⇌ 2 H2O(g) with Kc = 3.2 * 10^8, and the second reaction is N2(g) + 3 H2(g) ⇌ 2 NH3(g) with Kc = 3.5 * 10^8.
Write the target reaction: 4 NH3(g) + 3 O2(g) ⇌ 2 N2(g) + 6 H2O(g).
Break down the target reaction into reactions that involve the given equilibrium constants. This can be done by reversing the second given reaction and multiplying it by 2, and using the first given reaction multiplied by 3.
Calculate the equilibrium constant for the reversed reaction of NH3 formation by taking the reciprocal of the given Kc for that reaction, since reversing a reaction inverts its equilibrium constant (Kc' = 1/Kc).
Combine the equilibrium constants of the adjusted reactions using the rule that when reactions are added, their equilibrium constants are multiplied. For the reversed reaction, use the reciprocal value calculated in the previous step.
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
4mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Equilibrium Constant (Kc)
The equilibrium constant (Kc) 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. It is calculated using the formula Kc = [products]^[coefficients] / [reactants]^[coefficients]. A larger Kc indicates a greater concentration of products at equilibrium, while a smaller Kc suggests a higher concentration of reactants.
Recommended video:
Guided course
03:20
Equilibrium Constant Expressions
Reaction Stoichiometry
Reaction stoichiometry refers to the quantitative relationships between the reactants and products in a chemical reaction, as represented by their coefficients in the balanced equation. Understanding stoichiometry is essential for manipulating equilibrium constants, as it allows for the adjustment of the reaction's coefficients to derive the equilibrium constant for a different reaction based on known constants.
Recommended video:
Guided course
01:16Stoichiometry Concept
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. This principle is crucial when considering how changes in concentration, pressure, or temperature can affect the position of equilibrium and, consequently, the value of the equilibrium constant.
Recommended video:
Guided course
07:32Le Chatelier's Principle
Related Practice
Textbook Question
The reaction
2 PH31g2 + As21g2 ∆ 2 AsH31g2 + P21g2
has Kp = 2.9 * 10-5 at 873 K. At the same temperature,
what is Kp for each of the following reactions?
(a) 2 AsH31g2 + P21g2 ∆ 2 PH31g2 + As21g2
Textbook Question
Calculate the value of the equilibrium constant at 427 °C for the reaction
Na O1s2 + 1>2 O 1g2 ∆ Na O 1s2
given the following equilibrium constants at 427 °C.
Na2O1s2 ∆ 2 Na1l2 + 1>2 O21g2 Kc = 2 * 10-25 Na O 1s2 ∆ 2 Na1l2 + O 1g2 K = 5 * 10-29
Textbook Question
Consider the interconversion of A molecules (red spheres) and B molecules (blue spheres) according to the reaction A ∆ B. Each of the series of pictures at the right represents a separate experiment in which time increases from left to right:(b) What is the value of the equilibrium constant Kc for the reaction A ∆ B?
Textbook Question
The reaction A2 + B ∆ A + AB has an equilibrium con-stant Kc = 2. The following pictures represent reaction mix- tures that contain A atoms (red), B atoms (blue), and A2 and AB molecules. (a) Which reaction mixture is at equilibrium?
Textbook Question
The following pictures represent the initial state and the equilibrium state for the reaction of A2 molecules (red) with B atoms (blue) to give AB molecules. (a) Write a balanced chemical equation for the reaction.