Textbook Question
Which of the following alkenes would you expect to react fastest with HBr in each pair?
(b)
3
views
Ch. 8 - Alkenes I: Properties and Electrophilic Additions
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471
Not the one you use?Change textbookSelect a different textbook
Table of contents
- Ch. 2 - General Chemistry Translated: Finding the Electrons114
- Ch. 3 - Alkanes and Cycloalkanes: Properties and Conformational Analysis109
- Ch. 4 - Acids and Bases: Electron Flow144
- Ch. 5 - Chemical Reaction Analysis: Thermodynamics and Kinetics118
- Ch. 6 - Stereoisomerism: Arrangement of Atoms in Space112
- Ch. 7 - Principles of Green (Organic) Chemistry3
- Ch. 8 - Alkenes I: Properties and Electrophilic Additions158
- Ch. 9 - Alkenes II: Oxidation and Reduction150
- Ch. 10 - Alkynes: Electrophilic Addition and Redox Reactions101
- Ch. 11 - Properties and Synthesis of Alkyl Halides: Radical Reactions108
- Ch. 12 - Substitution and Elimination: Reactions of Haloalkanes172
- Ch. 13 - Alcohols, Ethers and Related Compounds: Substitution and Elimination239
- Ch. 14 - Structural Identification I: Infrared Spectroscopy and Mass Spectrometry54
- Ch. 15 - Structural Identification II: Nuclear Magnetic Resonance Spectroscopy93
- Ch. 16 - Metals in Organic Chemistry48
- Ch. 17 - Carbonyl Addition Reactions: Aldehydes and Ketones45
- Ch. 18 - Nucleophilic Acyl Substitution I: Carboxylic Acids18
- Ch. 19 - Nucleophilic Acyl Substitution II: Carboxylic Acid Derivatives39
- Ch. 20 - Enolates: Carbonyl Addition and Substitution13
- Ch. 21 - Conjugated Systems I: Stability and Addition Reactions56
- Ch. 22 - Conjugated Systems II: Pericyclic Reactions54
- Ch. 23 - Benzene I: Aromatic Stability and Substitution Reactions64
- Ch. 24 - Benzene II: Reactions Influenced by the Aromatic Ring62
- Ch. 25 - Amines: Structure, Reactions, and Synthesis27
- Ch. 26 - Amino Acids, Proteins, and Peptide Synthesis9
- Ch. 27 - Carbohydrates, Nucleic Acids, and Lipids54
Mullins1st EditionOrganic Chemistry: A Learner Centered ApproachISBN: 9780137566471Not the one you use?Change textbook
All textbooks
Mullins 1st EditionCh. 8 - Alkenes I: Properties and Electrophilic AdditionsProblem 66b
Mullins 1st EditionCh. 8 - Alkenes I: Properties and Electrophilic AdditionsProblem 66bChapter 7, Problem 66b
How many stereoisomers are possible for the following alkenes?
(b) 
Verified step by step guidance1
Step 1: Understand the concept of stereoisomers in alkenes. Stereoisomers are compounds with the same molecular formula and connectivity of atoms but differ in the spatial arrangement of atoms. For alkenes, stereoisomerism arises due to restricted rotation around the double bond, leading to cis-trans (or E/Z) isomerism.
Step 2: Analyze the structure of the given alkene. Determine if the double bond has two different groups attached to each carbon atom involved in the double bond. This is a requirement for cis-trans (E/Z) isomerism.
Step 3: Count the number of stereogenic centers (chiral centers or double bonds with distinct substituents) in the molecule. Each stereogenic center contributes to the number of possible stereoisomers.
Step 4: Use the formula for calculating the number of stereoisomers: \( 2^n \), where \( n \) is the number of stereogenic centers. This formula assumes that all stereogenic centers are independent and can adopt different configurations.
Step 5: Verify the structure for any symmetry or identical substituents that might reduce the number of stereoisomers. Symmetry can lead to fewer stereoisomers than predicted by \( 2^n \).
Verified video answer for a similar problem:
This video solution was recommended by our tutors as helpful for the problem above.
Video duration:
1mWas this helpful?
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Stereoisomerism
Stereoisomerism refers to the phenomenon where compounds have the same molecular formula and connectivity of atoms but differ in the spatial arrangement of their atoms. This can lead to different physical and chemical properties. In alkenes, stereoisomers arise due to the presence of a double bond, which restricts rotation and can create different configurations, such as cis and trans isomers.
Recommended video:
Guided course
01:58
Determining when molecules are stereoisomers.
Cis-Trans Isomerism
Cis-trans isomerism is a specific type of stereoisomerism that occurs in alkenes with two different substituents on each carbon of the double bond. In the cis configuration, similar groups are on the same side of the double bond, while in the trans configuration, they are on opposite sides. This distinction is crucial for determining the physical properties and reactivity of the alkenes.
Recommended video:
Guided course
00:44Is the following cyclohexane cis or trans?
Counting Stereoisomers
The number of possible stereoisomers for a compound can be determined using the formula 2^n, where n is the number of chiral centers or the number of double bonds with different substituents. For alkenes, if there are no chiral centers but multiple substituents, the presence of cis-trans isomerism must be considered, which can increase the total count of stereoisomers beyond just the chiral centers.
Recommended video:
Guided course
07:07Electron Counting
Related Practice
Textbook Question
Because of the angle strain present in cyclopropanes, they tend to open up in the presence of nearby radicals. Show a mechanism for the following reaction that demonstrates this principle.
1
views
Textbook Question
Cyclooctene is one of the smaller rings that can form a trans alkene. Would you expect cis-cyclooctene or trans-cyclooctene to react more quickly in an acid-catalyzed hydration reaction?
Textbook Question
How many stereoisomers are possible for the following alkenes?
(c)
Textbook Question
Which of the following cycloalkanes would you expect to produce the least heat upon combustion when measured per CH2? Explain your answer.
1
views
Textbook Question
How many stereoisomers are possible for the following alkenes?
(d)
1
views