Ch.7 - Quantum MechanicsWorksheetSee all chapters
All Chapters
Ch.1 - Intro to General Chemistry
Ch.2 - Atoms & Elements
Ch.3 - Chemical Reactions
BONUS: Lab Techniques and Procedures
BONUS: Mathematical Operations and Functions
Ch.4 - Chemical Quantities & Aqueous Reactions
Ch.5 - Gases
Ch.6 - Thermochemistry
Ch.7 - Quantum Mechanics
Ch.8 - Periodic Properties of the Elements
Ch.9 - Bonding & Molecular Structure
Ch.10 - Molecular Shapes & Valence Bond Theory
Ch.11 - Liquids, Solids & Intermolecular Forces
Ch.12 - Solutions
Ch.13 - Chemical Kinetics
Ch.14 - Chemical Equilibrium
Ch.15 - Acid and Base Equilibrium
Ch.16 - Aqueous Equilibrium
Ch. 17 - Chemical Thermodynamics
Ch.18 - Electrochemistry
Ch.19 - Nuclear Chemistry
Ch.20 - Organic Chemistry
Ch.22 - Chemistry of the Nonmetals
Ch.23 - Transition Metals and Coordination Compounds

Solution: Suppose you have two unlabeled flasks, and each flask contains one of these two compounds:Can you differentiate the compounds using a UV spectrophotometer? Select the true statement.a. The λmax of the compound with 2 conjugated bonds appears at a longer wavelength than does the λmax of the compound with 3 conjugated bonds. b. The λmax of the compound with 3 conjugated bonds appears at a longer wavelength than does the λmax of the compound with 2 conjugated bonds.c. The two compounds cannot be differentiated by their λmax values.

Problem

Suppose you have two unlabeled flasks, and each flask contains one of these two compounds:

Can you differentiate the compounds using a UV spectrophotometer? Select the true statement.

a. The λmax of the compound with 2 conjugated bonds appears at a longer wavelength than does the λmax of the compound with 3 conjugated bonds. 

b. The λmax of the compound with 3 conjugated bonds appears at a longer wavelength than does the λmax of the compound with 2 conjugated bonds.

c. The two compounds cannot be differentiated by their λmax values.

Solution

Conjugated dienes are chromophores which contribute colors to a compound by light absorption.

The greater the conjugation and resonance, the longer the wavelength absorbed by the compound.

When electrons absorb energy, they transition from a lower energy orbital to a higher energy orbital.

Highest Occupied Molecular Orbital (HOMO) → Lowest Unoccupied Molecular Orbital (LUMO)


Solution BlurView Complete Written Solution