Textbook Question
(b) The reaction 2 NO1g2 + Cl21g2¡2 NOCl1g2 is carried out in a closed vessel. If the partial pressure of NO is decreasing at the rate of 56 torr/min, what is the rate of change of the total pressure of the vessel?
Ch.14 - Chemical Kinetics
Chapter 14, Problem 27b
A reaction A + B → C obeys the following rate law: Rate = k[B]2. (b) What are the reaction orders for A and B? What is the overall reaction order?
Verified step by step guidance1
Identify the reaction order for each reactant from the rate law expression. The reaction order is the exponent of the concentration of each reactant in the rate law equation.
For reactant A, observe that it does not appear in the rate law expression. Therefore, the reaction order with respect to A is 0.
For reactant B, note the exponent of B in the rate law expression, which is 4. Thus, the reaction order with respect to B is 4.
Calculate the overall reaction order by summing the reaction orders of all reactants. In this case, add the reaction order of A and the reaction order of B.
The overall reaction order is the sum of the individual orders: 0 (order of A) + 4 (order of B) = 4.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Rate Law
A rate law expresses the relationship between the rate of a chemical reaction and the concentration of its reactants. It is typically formulated as Rate = k[A]^m[B]^n, where k is the rate constant, and m and n are the orders of the reaction with respect to reactants A and B, respectively. Understanding the rate law is essential for determining how changes in concentration affect the reaction rate.
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Rate Law Fundamentals
Reaction Order
The reaction order is the sum of the powers of the concentration terms in the rate law. It indicates how the rate of reaction is affected by the concentration of each reactant. For example, if the rate law is Rate = k[B]^2, the reaction is second order with respect to B, meaning that doubling the concentration of B will quadruple the reaction rate.
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00:36Average Bond Order
Overall Reaction Order
The overall reaction order is the total of the individual orders of all reactants in the rate law. It provides insight into the complexity of the reaction mechanism. In the given rate law, if A has an order of 1 and B has an order of 2, the overall reaction order would be 1 + 2 = 3, indicating how the reaction rate responds to changes in concentrations of all reactants.
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Related Practice
Textbook Question
A reaction A + B → C obeys the following rate law: Rate = k[B]2. (a) If [A] is doubled, how will the rate change? Will the rate constant change?
Textbook Question
A reaction A + B → C obeys the following rate law: Rate = k[B]2. (c) What are the units of the rate constant?
Textbook Question
Consider a hypothetical reaction between A, B, and C that is first order in A, zero order in B, and second order in C. (a) Write the rate law for the reaction.
Textbook Question
Consider a hypothetical reaction between A, B, and C that is first order in A, zero order in B, and second order in C. (b) How does the rate change when [A] is doubled and the other reactant concentrations are held constant? (c) How does the rate change when [B] is tripled and the other reactant concentrations are held constant? (d) How does the rate change when [C] is tripled and the other reactant concentrations are held constant? (f) By what factor does the rate change when the concentrations of all three reactants are cut in half?