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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6: minutes

Problem 26a

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)

Verified step by step guidance

Understand the concept of the frequency factor (A): The frequency factor is a component of the Arrhenius equation, which describes the rate constant (k) of a reaction. The equation is:

k = A e^{- \frac{E}{RT}}

. Here, A represents the frequency of collisions with the correct orientation for a reaction to occur.

Analyze the factors affecting the frequency factor (A): A depends on the molecular structure, size, and complexity of the reactants. Simpler molecules with fewer steric hindrances and more favorable orientations for collisions typically have higher values of A.

Compare the molecular structures of the reactants in the given pairs: Examine the size, complexity, and steric hindrance of the molecules in each pair. Simpler and less hindered molecules are expected to have a higher frequency factor.

Consider the reaction mechanism: If one reaction involves a simpler mechanism (e.g., fewer steps or less steric hindrance in the transition state), it is likely to have a higher frequency factor.

Select the faster reaction based on A: Based on the analysis of molecular structure and reaction mechanism, identify which reaction in the pair is expected to have a higher frequency factor and thus proceed faster.

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Key Concepts

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

Frequency Factor (A)

The frequency factor, often denoted as A in the Arrhenius equation, represents the frequency of collisions between reactant molecules that can lead to a reaction. A higher frequency factor indicates that the reactants are more likely to collide in the correct orientation and with sufficient energy to overcome the activation energy barrier, thus increasing the reaction rate.

Activation Energy (Ea)

Activation energy is the minimum energy required for a chemical reaction to occur. It is a crucial factor in determining the rate of a reaction; reactions with lower activation energies tend to proceed faster because a greater proportion of the reactant molecules have enough energy to overcome this barrier during collisions.

Reaction Mechanism

A reaction mechanism is a step-by-step description of the pathway taken by reactants to form products. Understanding the mechanism helps in predicting which reactions will be faster, as it provides insight into the number of elementary steps involved and the energy changes associated with each step, influencing both the frequency factor and activation energy.

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Related Practice

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

Textbook Question

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

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.

Textbook Question

For rotation around a bond, the rate constant is equal to the reaction rate. Why?

Textbook Question

The rate constant for the uncatalyzed reaction of two molecules of glycine ethyl ester to form glycylglycine ethyl ester is 0.6 M^-1 s^-1. In the presence of Co²⁺, the rate constant is 1.5 × 10⁶ M^-1 s^-1. What rate enhancement does the catalyst provide?

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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)

Key Concepts

Frequency Factor (A)

Activation Energy (Ea)

Reaction Mechanism

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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)