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Ch.14 - Chemical Kinetics
Tro - Chemistry: A Molecular Approach 4th Edition
Tro4th EditionChemistry: A Molecular ApproachISBN: 9780134112831Not the one you use?Change textbook
All textbooksTro 4th EditionCh.14 - Chemical KineticsProblem 34c
Chapter 14, Problem 34c

Consider the reaction: 2 H2O2(aq) → 2 H2O(l ) + O2( g) The graph shows the concentration of H2O2 as a function of time.
Use the graph to calculate each quantity: c. the instantaneous rate of formation of O2 at 50 s

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1
Determine the slope of the tangent line to the curve at 50 seconds on the graph of H_2O_2 concentration versus time.
Use the stoichiometry of the reaction: 2 H_2O_2(aq) → 2 H_2O(l) + O_2(g) to relate the rate of disappearance of H_2O_2 to the rate of formation of O_2.
The rate of formation of O_2 is half the rate of disappearance of H_2O_2, due to the stoichiometric coefficients in the balanced equation.
Calculate the instantaneous rate of formation of O_2 by taking half of the slope determined in the first step.
Express the rate in appropriate units, typically mol/L·s, based on the units used in the graph.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Reaction Rate

The reaction rate refers to the speed at which reactants are converted into products in a chemical reaction. It can be expressed as the change in concentration of a reactant or product over time. Understanding how to calculate reaction rates is essential for analyzing chemical kinetics and determining how quickly a reaction proceeds.
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Average Rate of Reaction

Instantaneous Rate

The instantaneous rate of a reaction is the rate at a specific moment in time, rather than over an interval. It can be determined by taking the slope of the tangent line to the concentration vs. time graph at the desired time point. This concept is crucial for accurately assessing how fast a product is being formed or a reactant is being consumed at any given moment.
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Stoichiometry

Stoichiometry involves the quantitative relationships between the reactants and products in a chemical reaction, based on the balanced chemical equation. In the given reaction, the stoichiometric coefficients indicate that for every 2 moles of H2O2 decomposed, 1 mole of O2 is produced. This relationship is vital for converting the rate of formation of one substance into the rate of formation of another.
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Related Practice
Textbook Question

This graph shows a plot of the rate of a reaction versus the concentration of the reactant A for the reaction A → products. c. Write a rate law for the reaction including an estimate for the value of k.

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Textbook Question

This graph shows a plot of the rate of a reaction versus the concentration of the reactant A for the reaction A → products. a. What is the order of the reaction with respect to A?

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Textbook Question

Consider the reaction: 2 H2O2(aq) → 2 H2O(l ) + O2( g) The graph shows the concentration of H2O2 as a function of time. Use the graph to calculate each quantity: d. If the initial volume of the H2O2 is 1.5 L, what total amount of O2 (in moles) is formed in the first 50 s of reaction?

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Textbook Question

Consider the reaction: H2( g) + Br2( g) → 2 HBr( g) The graph shows the concentration of Br2 as a function of time.

b. Make a rough sketch of a curve representing the concentration of HBr as a function of time. Assume that the initial concentration of HBr is zero

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