/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 18 There is often one step in a rea... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 13: Problem 18

There is often one step in a reaction mechanism that is rate-determining. What characteristic of such a step makes it rate-determining? Explain.

Short Answer

Expert verified
The rate-determining step is the slowest step with the highest activation energy.

Step by step solution

01

Understanding the Reaction Mechanism

A reaction mechanism details the step-by-step sequence of elementary reactions by which overall chemical change occurs. In any mechanism, each step has its own rate.
02

Definition of Rate-Determining Step

The rate-determining step is the slowest step in the reaction mechanism. It acts like a bottleneck, limiting the overall rate of the reaction because it has the highest activation energy compared to other steps.
03

Analyzing Activation Energy

The rate of a chemical reaction is primarily determined by the activation energy of its slowest step since it requires more energy to overcome than other steps. So, a higher activation energy means a slower reaction rate, making it a rate-determining step.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Understanding Reaction Mechanism
A reaction mechanism is like the blueprint of a chemical reaction. It describes the tiny steps, known as elementary reactions, that lead to the transformation of reactants into products. Think of it as a series of doorways - each doorway representing a step that the chemical substances must pass through on their journey. Not every step happens at the same speed. Some doorways are narrow and difficult to pass through, while others are wide and easy.
  • Each step of the mechanism has its own speed or rate.
  • Some steps happen quickly, and some are slow.
  • The overall chemical change occurs through this complete sequence of steps.
By understanding the reaction mechanism, chemists can predict how changes in conditions will affect the speed and outcome of the reaction.
Exploring Activation Energy
Activation energy is the energy hill that reactants need to climb to transform into products. Imagine trying to roll a ball over a hill; the higher the hill, the more effort needed. In chemistry, this effort is the activation energy. It's the minimum energy that must be supplied for a reaction to occur.
  • A high activation energy means the reaction needs more energy, making it slower.
  • A low activation energy means the reaction can proceed faster with less energy.
  • The step with the highest activation energy is often the slowest step (rate-determining step) because it's the hardest hurdle to overcome.
Activation energy is crucial because it influences the reaction rate and determines which step is the rate-determining one. It acts like the gatekeeper in the reaction mechanism.
Defining Reaction Rate
The reaction rate tells us how fast reactants are turning into products. It's like timing how quickly a baker can turn raw dough into fresh bread. The rate of reaction depends on several factors, including the concentration of reactants, temperature, and the presence of catalysts.
  • A greater concentration of reactants generally leads to a faster reaction rate.
  • Higher temperatures increase particle movement, leading to more effective collisions, speeding up the reaction.
  • Catalysts lower activation energy, facilitating a quicker reaction without being consumed.
The reaction rate is directly tied to the steps within the reaction mechanism. The slowest step is crucial as it holds up the entire process, making it the rate-determining step. By understanding and adjusting these factors, chemists can control the speed of a chemical reaction.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

In the presence of a tungsten catalyst at high temperatures, the decomposition of ammonia to nitrogen and hydrogen is a zero-order process. If the rate constant at a particular temperature is \(3.7 \times 10^{-6} \mathrm{~mol} /(\mathrm{L} \cdot \mathrm{s}),\) how long will it take for the ammonia concentration to drop from an initial concentration of \(5.0 \times 10^{-4} M\) to \(5.0 \times 10^{-5} M\) ? What is the half-life of the reaction under these conditions?

Methyl isocyanide, \(\mathrm{CH}_{3} \mathrm{NC}\), isomerizes, when heated, to give acetonitrile (methyl cyanide), \(\mathrm{CH}_{3} \mathrm{CN}\). $$ \mathrm{CH}_{3} \mathrm{NC}(g) \longrightarrow \mathrm{CH}_{3} \mathrm{CN}(g) $$ The reaction is first order. At \(230^{\circ} \mathrm{C}\), the rate constant for the isomerization is \(6.3 \times 10^{-4} / \mathrm{s}\). What is the half- life? How long would it take for the concentration of \(\mathrm{CH}_{3} \mathrm{NC}\) to decrease to \(50.0 \%\) of its initial value? to \(12.5 \%\) of its initial value?

Relate the rate of decomposition of \(\mathrm{NH}_{4} \mathrm{NO}_{2}\) to the rate of formation of \(\mathrm{N}_{2}\) for the following reaction: $$ \mathrm{NH}_{4} \mathrm{NO}_{2}(a q) \longrightarrow \mathrm{N}_{2}(g)+2 \mathrm{H}_{2} \mathrm{O}(l) $$

Given the following mechanism for a chemical reaction: $$ \begin{aligned} \mathrm{H}_{2} \mathrm{O}_{2}+\mathrm{I}^{-} \longrightarrow & \mathrm{H}_{2} \mathrm{O}+\mathrm{IO}^{-} \\ \mathrm{H}_{2} \mathrm{O}_{2}+\mathrm{IO}^{-} \longrightarrow & \mathrm{H}_{2} \mathrm{O}+\mathrm{O}_{2}+\mathrm{I}^{-} \end{aligned} $$ a. Write the overall reaction. b. Identify the catalyst and the reaction intermediate. c. With the information given in this problem, can you write the rate law? Explain.

Ethyl chloride, \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{Cl}\), used to produce tetraethyllead gasoline additive, decomposes, when heated, to give ethylene and hydrogen chloride. The reaction is first order. In an experiment, the initial concentration of ethyl chloride was \(0.00100 \mathrm{M}\). After heating at \(500^{\circ} \mathrm{C}\) for \(155 \mathrm{~s}\), this was reduced to \(0.00067 \mathrm{M}\). What was the concentration of ethyl chloride after a total of \(256 \mathrm{~s}\) ?
See all solutions

Recommended explanations on Chemistry Textbooks

Making Measurements

Read Explanation

Physical Chemistry

Read Explanation

The Earths Atmosphere

Read Explanation

Kinetics

Read Explanation

Nuclear Chemistry

Read Explanation

Inorganic Chemistry

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.