Table of contents

1. A Review of General Chemistry5h 5m
2. Molecular Representations1h 14m
3. Acids and Bases2h 46m
4. Alkanes and Cycloalkanes4h 17m
5. Chirality3h 39m
6. Thermodynamics and Kinetics1h 22m
7. Substitution Reactions1h 48m
8. Elimination Reactions2h 30m
9. Alkenes and Alkynes2h 9m
10. Addition Reactions3h 19m
11. Radical Reactions1h 58m
12. Alcohols, Ethers, Epoxides and Thiols2h 42m
13. Alcohols and Carbonyl Compounds2h 17m
14. Synthetic Techniques1h 26m
15. Analytical Techniques:IR, NMR, Mass Spect7h 3m
16. Conjugated Systems6h 13m
17. Ultraviolet Spectroscopy51m
18. Aromaticity2h 34m
19. Reactions of Aromatics: EAS and Beyond5h 1m
20. Phenols55m
21. Aldehydes and Ketones: Nucleophilic Addition4h 56m
22. Carboxylic Acid Derivatives: NAS2h 51m
23. The Chemistry of Thioesters, Phophate Ester and Phosphate Anhydrides1h 10m
24. Enolate Chemistry: Reactions at the Alpha-Carbon1h 53m
25. Condensation Chemistry2h 9m
26. Amines1h 43m
27. Heterocycles2h 0m
28. Carbohydrates5h 53m
29. Amino Acids4h 20m
30. Peptides and Proteins2h 42m
31. Catalysis in Organic Reactions1h 30m
32. Lipids 2h 50m
33. The Organic Chemistry of Metabolic Pathways2h 52m
34. Nucleic Acids1h 32m
35. Transition Metals6h 14m
36. Synthetic Polymers1h 49m

6. Thermodynamics and Kinetics

Energy Diagram

Organic Chemistry

6. Thermodynamics and Kinetics

Energy Diagram

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7:22 minutes

Problem 10a

Textbook Question

Given the following rate data, how many molecules are in the rate-determining step of this reaction?

Verified step by step guidance

Analyze the rate law provided in the problem or deduce it from the given rate data. The rate law is typically expressed as:

r = k {[A]}^{m} {[B]}^{n}

, where

m

and

n

are the reaction orders with respect to reactants A and B.

Determine the overall reaction order by summing the exponents in the rate law:

m + n

. This overall order corresponds to the number of molecules involved in the rate-determining step (also called the molecularity of the step).

Compare the molecularity deduced from the rate law to the proposed mechanism in Chapter 8. Identify the step in the mechanism that matches the molecularity and confirm whether it aligns with the rate-determining step.

Verify that the rate-determining step involves the correct reactants and intermediates as indicated by the rate law. For example, if the rate law includes

[A]

and

[B]

, ensure that these species are present in the slow step of the mechanism.

Conclude whether the mechanism provided in Chapter 8 is consistent with the rate law and the molecularity of the rate-determining step. If inconsistencies are found, suggest possible adjustments to the mechanism to align with the observed rate law.

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Key Concepts

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

Rate-Determining Step

The rate-determining step (RDS) is the slowest step in a reaction mechanism that determines the overall reaction rate. It acts as a bottleneck, meaning that the speed of the entire reaction cannot exceed the speed of this step. Understanding the RDS is crucial for analyzing reaction kinetics and predicting how changes in conditions can affect the reaction rate.

Molecularity

Molecularity refers to the number of reactant molecules involved in an elementary step of a reaction mechanism. It can be unimolecular (one molecule), bimolecular (two molecules), or termolecular (three molecules). The molecularity of the rate-determining step is essential for determining the rate law and understanding how reactant concentrations influence the reaction rate.

Reaction Mechanism

A reaction mechanism is a step-by-step description of the pathway taken by reactants to form products. It includes all elementary steps, intermediates, and the rate-determining step. Understanding the mechanism is vital for correlating experimental rate data with theoretical predictions, allowing chemists to validate or refine their models of how reactions occur.

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Related Practice

Textbook Question

Under certain conditions, the bromination of cyclohexene follows an unusual rate law:

a. What is the kinetic order with respect to cyclohexene?

Textbook Question

The molecule A undergoes a three-step reaction to make B, where the first step is rate determining. Conversely, C can be produced by A in a two-step reaction where the second step is rate determining. Show a reaction coordinate diagram for each reaction, making it clear that the reaction to make C is faster than the reaction to make B.

Textbook Question

Under certain conditions, the bromination of cyclohexene follows an unusual rate law:

b. What is the kinetic order with respect to bromine?

Textbook Question

How will the rate of the reaction between bromomethane and hydroxide ion be affected if the following changes in concentration are made?

b. The concentration of the alkyl halide is cut in half and the concentration of the nucleophile is not changed.

Textbook Question

Given that step 1 of the following reaction is rate determining, write the rate law for the overall reaction.

Textbook Question

Within the following pairs, pick which reaction you would expect to be faster based on having a higher value of the frequency factor (A).

(a)

Textbook Question

Parts (a)–(f) of this assessment refer to the rotation around the single bond of ethane.

(a) Given that the rate of the reaction is independent of concentration, fill in the missing rates in the following table.

Textbook Question

How will the rate of the reaction between bromomethane and hydroxide ion be affected if the following changes in concentration are made?

a. The concentration of the alkyl halide is not changed and the concentration of the nucleophile is tripled.

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