Predict the approximate bond angles for c. the H—C—N bond angle in (CH 3 ) 2 NH. d. the H—C—O bond angle in CH 3 OCH 3

All right. Hello everyone. So for this question, let's go ahead and estimate the angles or number one, the HC bond angle in the ether diho ether. And for part two, the HC and bond angle in the secondary amine diho amine, here we have four different entry choices labeled A through D proposing different bond angles or parts one and two, ranging from 120 degrees to 109.5 degrees. So lets go ahead and get started with part one which is die eho Ether to understand the Lewis structure of an ether. Recall that they have the general Lewis structure of Ror and oxygen contains two lone pairs of electrons as well as two covalent bonds to fulfill its octet according to its bonding preferences. Now recall that art is an abbreviation for the carbon chain on either side of the ether's oxygen. In this case, we just so happen to have the same exact group which is an ethyl group on either side of oxygen. So in this case, I'm going to replace the R group on either side with the ethel group here. Now, when drawing out the art groups recall that the atom with the higher bond preference should be in the middle carbon prefers four bonds, whereas hydrogen prefers only one bond. So because of this carbon goes in the center, so I have two carbons here in the center on one side of oxygen and then we have hydrogen atoms connecting to the carbon atoms. So on the other side, I'm going to do the same thing and add the same R group. So now let's talk about the bond angle recall that the bond angle is determined by considering three atoms that create two bonds in between them. And the angle is determined by the atom in the center of the angle. In question. In this case of the HCO bond angle, the atom in the center is carbon. So the angle is determined by the hybridization on carbon recalled hybridization is determined by the number of quote unquote groups that surround a given target at them. And groups fall into two distinct categories for our purposes. Here, we have electron pairs and other atoms connecting to the atom of interest. Both of these things classify as quote unquote groups. So focusing our attention on carbon, we have zero loan pairs of electrons, but we have four other atoms connecting to carbon. This ultimately makes four groups in total, which corresponds to sp three hybridization. So because the point of reference in the HCO bond angle is carbon and carbon is sp three hybridized with zero load pairs, the bond angle is going to be approximately 109.5 degrees. So that concludes part one and now lets apply the same procedure here to part two. Now part two is a secondary amine which has a general lewis structure of one nitrogen atom connecting to two R groups and one hydrogen atom with one lone pair of electrons on nitrogen. This is because nitrogen prefers to have actually three bonds and only one lone pair of electrons to satisfy its octet. So using the same rules as before, we're going to substitute the R groups of the general Lewis structure with the R groups in the given amen, which once again happened to be ethel groups. So here I'm going to make some space for myself and at the center of the R group should be carbon since it has a higher bond preference than hydrogen. So I have carbon in the center and hydrogens attached to carbon. And so I'm going to do the same thing here on the other side of nitrogen since both our groups are the same. So this time for part two, we're examining the HCN one angle, which means that carbon is once again the center or the reference point. So considering the lowest structure of diy amine, we have zero lone pairs of electrons around carbon and four other atoms connecting directly to carbon. This makes four groups in total and corresponds to SB three hybridization on carbon because carbon is the point of reference for this bond angle. And carbon itself is P three hybridized with no lone pairs. The bond angle should once again be approximately 109.5 degrees. And there you have it. This means that our answer is option c in the multiple choice where both parts one and two are approximately 109.5 degrees. So with that being said, thank you so very much for watching and I hope you found this helpful.

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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

1. A Review of General Chemistry

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1. A Review of General Chemistry

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7:05 minutes

Problem 45c,d

Textbook Question

Predict the approximate bond angles for
c. the H—C—N bond angle in (CH₃)₂NH.
d. the H—C—O bond angle in CH₃OCH₃

Verified step by step guidance

Step 1: Understand the molecular geometry of the compounds. For (CH3)2NH, the nitrogen atom is sp3 hybridized, and the molecule has a trigonal pyramidal geometry due to the lone pair on nitrogen. For CH3OCH3, the oxygen atom is sp3 hybridized, and the molecule has a bent geometry due to the two lone pairs on oxygen.

Step 2: Recall the ideal bond angles for sp3 hybridized atoms. In a perfect tetrahedral geometry, the bond angles are approximately 109.5°. However, lone pairs exert greater repulsion than bonding pairs, which reduces the bond angles slightly.

Step 3: For (CH3)2NH, the lone pair on nitrogen causes the H—C—N bond angle to be slightly less than 109.5°. The repulsion from the lone pair compresses the bond angle, making it closer to approximately 107°.

Step 4: For CH3OCH3, the two lone pairs on oxygen exert repulsion on the bonding pairs, reducing the H—C—O bond angle. This bond angle is slightly less than 109.5°, typically around 104.5°.

Step 5: Summarize the reasoning: The bond angles are influenced by the hybridization of the central atom and the repulsion caused by lone pairs. Lone pairs reduce bond angles compared to the ideal tetrahedral angle of 109.5°.

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Key Concepts

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

VSEPR Theory

Valence Shell Electron Pair Repulsion (VSEPR) Theory is a model used to predict the geometry of individual molecules based on the repulsion between electron pairs in the valence shell of the central atom. According to VSEPR, electron pairs will arrange themselves to minimize repulsion, leading to specific bond angles characteristic of different molecular shapes.

Hybridization

Hybridization is the concept of mixing atomic orbitals to form new hybrid orbitals that can accommodate bonding. In organic molecules, carbon typically undergoes sp3 hybridization, resulting in tetrahedral geometry with bond angles of approximately 109.5 degrees, while nitrogen can exhibit sp3 hybridization as well, influencing the bond angles in amines like (CH3)2NH.

Molecular Geometry

Molecular geometry refers to the three-dimensional arrangement of atoms within a molecule. The geometry is determined by the number of bonding pairs and lone pairs of electrons around the central atom, which directly influences bond angles. For example, in CH3OCH3, the presence of lone pairs on oxygen affects the H—C—O bond angle, leading to deviations from the ideal tetrahedral angle.

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Predict the approximate bond angles forc. the H—C—N bond angle in (CH3)2NH.d. the H—C—O bond angle in CH3OCH3

Key Concepts

VSEPR Theory

Hybridization

Molecular Geometry

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Predict the approximate bond angles for
c. the H—C—N bond angle in (CH₃)₂NH.
d. the H—C—O bond angle in CH₃OCH₃