Domanda del libro di testo
At pH = 7, one of the ions shown here is purple and the other is blue. Which is which?
1325
views
Ch. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis Spectroscopy
Bruice8th EditionOrganic ChemistryISBN: 9780135213711
Non è quello che usi tu?Cambia libro di testoScegli un libro di testo diverso
TOC.tableOfContents
- Ch. 1 - Remembering General Chemistry: Electronic Structure and Bonding31
- Ch. 2 - Acids and Bases: Central to Understanding Organic Chemistry84
- Ch. 3 - An Introduction to Organic Compounds: Nomenclature, Physical Properties, and Structure183
- Ch. 4 - Isomers: The Arrangement of Atoms in Space121
- Ch. 5 - Alkenes: Structure, Nomenclature, and an Introduction to Reactivity • Thermodynamics and Kinetics83
- Ch. 6 - The Reactions of Alkenes • The Stereochemistry of Addition Reactions175
- Ch. 7 - The Reactions of Alkynes • An Introduction to Multistep Synthesis119
- Ch. 8 - Delocalized Electrons: Their Effect on Stability, pKa, and the Products of a Reaction • Aromaticity and Electronic Effects: An Introduction to the Reactions of Benzene148
- Ch. 9 - Substitution and Elimination Reactions of Alkyl Halides212
- Ch. 10 - Reactions of Alcohols, Ethers, Epoxides, Amines, and Sulfur-Containing Compounds131
- Ch. 11 - Organometallic Compounds60
- Ch. 12 - Radicals90
- Ch. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis Spectroscopy62
- Ch. 14 - NMR Spectroscopy95
- Ch. 15 - Reactions of Carboxylic Acids and Carboxylic Acid Derivatives123
- Ch. 16 - Reactions of Aldehydes and Ketones • More Reactions of Carboxylic Acid Derivatives141
- Ch. 17 - Reactions at the Alpha-Carbon101
- Ch. 18 - Reactions of Benzene and Substituted Benzenes144
- Ch. 19 - More About Amines • Reactions of Heterocyclic Compounds49
- Ch. 20 - The Organic Chemistry of Carbohydrates80
- Ch. 21 - Amino Acids, Peptides, and Proteins57
- Ch. 22 - Catalysis in Organic Reactions and in Enzymatic Reactions35
- Ch. 23 - The Organic Chemistry of the Coenzymes—Compounds Derived from Vitamins1
- Ch. 28 - Pericyclic Reactions58
Tutti i libri di testo
Bruice 8th EditionCh. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis SpectroscopyProblema 37b
Bruice 8th EditionCh. 13 - Mass Spectrometry; Infrared Spectroscopy; UV/Vis SpectroscopyProblema 37bCapitolo 13, Problema 37b
Rank each set of compounds in order of decreasing λmax:
b. 
Guida verificata passo dopo passo1
Step 1: Understand the concept of λmax (maximum wavelength of absorption). λmax is influenced by the extent of conjugation in a molecule. Greater conjugation leads to a longer λmax due to lower energy transitions between molecular orbitals.
Step 2: Analyze compound A. It contains an aromatic ring (benzene) conjugated with a nitrogen atom. The lone pair on the nitrogen can participate in resonance with the aromatic ring, increasing conjugation and λmax.
Step 3: Analyze compound B. It has a saturated cyclohexane ring with no conjugation. The nitrogen atom is not part of a conjugated system, so this compound will have the shortest λmax.
Step 4: Analyze compound C. Similar to compound A, it has an aromatic ring conjugated with a nitrogen atom. However, the nitrogen in compound C is part of a dimethylamino group, which is electron-donating and enhances resonance, potentially increasing λmax compared to A.
Step 5: Analyze compound D. It contains an aromatic ring conjugated with a positively charged nitrogen atom. The positive charge reduces the ability of the nitrogen to donate electrons into the aromatic ring, decreasing conjugation compared to A and C, but still higher than B.
Risposta video verificata per un problema simile:
Questa soluzione video è stata consigliata dai nostri tutor come utile per risolvere questo problema.
Durata del video:
3mConcetti chiave
Ecco i concetti essenziali che devi comprendere per rispondere correttamente alla domanda.
Conjugation
Conjugation refers to the overlap of p-orbitals across adjacent double bonds or lone pairs, allowing for delocalization of electrons. This delocalization lowers the energy of the molecule and can increase the wavelength of light absorbed (lmax). In the context of the compounds shown, the extent of conjugation will influence their respective lmax values.
Video consigliato:
03:27
Conjugated states
Electron-Withdrawing and Electron-Donating Groups
The presence of electron-withdrawing groups (EWGs) or electron-donating groups (EDGs) can significantly affect the electronic properties of a compound. EWGs tend to lower the energy of the highest occupied molecular orbital (HOMO), while EDGs raise it, thus influencing the lmax. In the provided structures, the nature of the substituents on the aromatic ring will determine their lmax ranking.
Video consigliato:
02:37Donating vs Withdrawing Groups
Aromaticity
Aromatic compounds are characterized by their cyclic structure, planar geometry, and delocalized pi electrons, which contribute to their stability and unique electronic properties. The degree of aromaticity can affect the lmax, as more stable aromatic systems with greater electron delocalization typically absorb light at longer wavelengths. The structures A, B, C, and D will exhibit varying levels of aromaticity, impacting their lmax values.
Video consigliato:
08:19Intro to Aromaticity
Pratica correlata
Domanda del libro di testo
In the mass spectrum of the following compounds, which is the tallest—the peak at m/z = 57 or the peak at m/z = 71?
a. 3-methylpentane
b. 2-methylpentane
1295
views
Domanda del libro di testo
Rank each set of compounds in order of decreasing λmax:
a.
1593
views
Domanda del libro di testo
A 4.0 × 10-5 M solution of a compound in hexane shows an absorbance of 0.40 at 252 nm in a cell with a 1 cm light path. What is the molar absorptivity of the compound in hexane at 252 nm?
1345
views
Domanda del libro di testo
What would be the difference in the colors of the compounds at pH = 3?
938
views
Domanda del libro di testo
Predict the λmax of the following compound:
1883
views