Interpretation:
In Figure D-10a and D-10b, every region of constructive interference and destructive interference between the HOMO and LUMO is to be labeled.
Concept introduction:
Molecular orbitals are constructed from the AOs of different atoms. When two atoms are brought close enough together (i.e., about a bond length apart), the AOs of one atom significantly overlap the AOs of the other atom, enabling them to undergo constructive and destructive interference, or mix, to produce new orbitals. When two orbitals overlap with the same phases, constructive interference takes place. When two orbitals overlap with the opposite phases, destructive interference takes place. Constructive interference results in a new orbital that is more stable than the σ bonding orbital, and destructive interference results in a new orbital that is less stable than the ρ atomic orbital. Constructive interference predominantly takes place in both Figure D-10a and Figure D-10b
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Chapter D Solutions
ORGANIC CHEMISTRY PRINCIPLES & MECHANISM
- At each wavelength, the Beer-Lambert equation states that absorbance is proportional to concentration. For quantitative concentration estimations, any wavelength might theoretically be used. However, we usually choose the wavelength with the highest absorbance for a specific sample and utilize that in our absorbance measurements. The steeper parts of the spectrum should be avoided. Why?arrow_forward2. According to the Beer-Lambert law absorbance is proportional to concentration at each wavelength. In principle, one could choose any wavelength for quantitative estimations of concentration. However, we generally select the wavelength of maximum absorbance for a given sample and use it in our absorbance measurements. Especially, one should avoid the steep portions of the spectrum. Why? 3. Which concentration range a dilute or a concentrated one - is chosen for accurate determinations of unknown concentrations?arrow_forwardCalculation of Optical rotation.arrow_forward
- What type of stretching results in IR absorption?arrow_forwardHow much energy is due to the additional steric strain of the 1,3-diaxial interaction?arrow_forward5. Calculate the percent transmittance of B-carotene that has an absorbance of 0.5 when analysed using a UV-Visible spectrophotometer. O 6.83 % O 31.6 % O 0.32 % O 68.3 %arrow_forward
- Here is the visible absorbance spectrum and electromagnetic spectrum. 1. Determine which molecule (a,b,c, or d) has the smaller HOMO-LUMO gap. Briefly explainyour reasoning. rememeber more conjugation is a smaller gap.arrow_forwardA1.50 g sample of conine sample was dissolved in 10.0 ml of ethanol and placed in a sample cell with a 5.00 cm pathlength. The observed rotation at the sodium d line was 11.21 Calculate (alo for conine.arrow_forwardAnswer number 1 to 5 and pls follow the instruction on the first picture.arrow_forward
- True or False 1. A strong signal in infrared spectroscopy indicates that a molecule matches the emitted electromagnetic radiation and reports a high transmittance. 2. Among all the possible vibrational modes, symmetric stretching will be IR inactive. 3. A hygroscopic organic sample to be subjected to IR does not need to be kept dry because water molecules in the air will not affect the IR spectra.arrow_forwardIf you goop on more sunscreen to double its thickness, absorbance will be doubled. What will be the transmittance near 300 nm and what percentage of ultraviolet radiation is blocked?arrow_forward5 identify the bands of functional groups from the molecule of the irarrow_forward
