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

5. Chirality

Test 1:Plane of Symmetry

Organic Chemistry

5. Chirality

Test 1:Plane of Symmetry

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4:52 minutes

Problem 93e

Textbook Question

Draw structures for the following:
e. two achiral stereoisomers of 3,4,5-trimethylheptane

Verified step by step guidance

Step 1: Understand the term 'achiral stereoisomers'. Achiral molecules are those that have a superimposable mirror image, meaning they do not have a chiral center. Stereoisomers are molecules that have the same molecular formula and sequence of bonded atoms, but differ in the three-dimensional orientations of their atoms in space.

Step 2: Draw the structure of 3,4,5-trimethylheptane. This is a heptane molecule (7 carbon atoms in a straight chain) with methyl groups (CH3) attached to the 3rd, 4th, and 5th carbon atoms.

Step 3: Identify the chiral centers. In this case, there are no chiral centers in 3,4,5-trimethylheptane because none of the carbon atoms have four different groups attached to them.

Step 4: Draw two different stereoisomers. Since the molecule is achiral, the stereoisomers will be 'conformational isomers', which differ by rotation around a single bond. For example, you could draw one isomer with all three methyl groups on the same side of the molecule (all 'up' or all 'down'), and another isomer with one methyl group on one side and two on the other.

Step 5: Verify that the two structures you have drawn are indeed different, and that they are both achiral. They should be mirror images of each other that can be superimposed, confirming that they are achiral.

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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 those atoms. This can lead to different physical and chemical properties. In organic chemistry, stereoisomers can be classified into enantiomers and diastereomers, with the former being non-superimposable mirror images and the latter not being mirror images.

Chirality

Chirality is a property of a molecule that makes it non-superimposable on its mirror image, much like left and right hands. A chiral molecule typically has a carbon atom bonded to four different substituents, creating two distinct enantiomers. In contrast, achiral molecules possess a plane of symmetry and can be superimposed on their mirror images, which is crucial for understanding the types of stereoisomers present in a compound.

Structural Isomers

Structural isomers are compounds that share the same molecular formula but differ in the connectivity of their atoms. This can include variations in the arrangement of carbon chains or functional groups. In the case of 3,4,5-trimethylheptane, identifying achiral stereoisomers involves recognizing different structural arrangements that do not create chirality, allowing for the drawing of distinct yet non-chiral forms.

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Related Practice

Textbook Question

Identify the following molecules as chiral or achiral. If chiral, draw the nonsuperimposable mirror image and verify its nonsuperimposability.

(e)

Textbook Question

Which of the following objects are chiral?

a. a mug with DAD written to one side of the handle

b. a mug with MOM written to one side of the handle

c. a mug with DAD written opposite the handle

d. a mug with MOM written opposite the handle

Textbook Question

Which of the following objects are chiral?

e. a wheelbarrow

f. a remote control device

g. a nail

h. screw

Textbook Question

Draw structures for the following:

d. a chiral stereoisomer of 1,2-dibromocyclobutane

Textbook Question

For each compound, determine whether the molecule has an internal mirror plane of symmetry. If it does, draw the mirror plane on a three-dimensional drawing of the molecule. If the molecule does not have an internal mirror plane, determine whether the structure is chiral.

(h)

Textbook Question

Classify the following objects and molecules as chiral or achiral.

(e)

Textbook Question

Identify all planes of symmetry in the following molecules/conformations, if any.

(d)

Multiple Choice

Which of the following molecules has a plane of symmetry?

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