PHYSICAL CHEMISTRY REVISION QUESTIONS 2024/2025. THE LATEST REVISION QUESTIONS AND CORRECT ANSWERS IN 2024/2025. (ALREADY GRADED A+) (LATEST 2024 UPDATE)
0 view 0 purchase
Course
PHYSICAL CHEMISTRY
Institution
PHYSICAL CHEMISTRY
What are the selection rules for rotational spectroscopy? - ANSWER- The molecule must
possess a permanent dipole
∆J = ±1
What is the gross and specific selection rule for vibrational spectroscopy? - ANSWER- Gross:
there must be a change in dipole moment of the molecule during the vibration
...
PHYSICAL CHEMISTRY REVISION QUESTIONS 2024/2025. THE LATEST
REVISION QUESTIONS AND CORRECT ANSWERS IN 2024/2025. (ALREADY
GRADED A+) (LATEST 2024 UPDATE)
What are the selection rules for rotational spectroscopy? - ANSWER- The molecule must
possess a permanent dipole
∆J = ±1
What is the gross and specific selection rule for vibrational spectroscopy? - ANSWER- Gross:
there must be a change in dipole moment of the molecule during the vibration
Specific: ∆v = ±1
The frequency of oscillation is given by: - ANSWER- ν = 1/2π(kf/μ)^1/2
kf = force constant (N m-1)
What is the equation for the energy of the vth
energy level? - ANSWER- Ev = (v + 0.5)hν
v = vibrational quantium number
ν = frequency of oscillation
How many vibrational nodes does a linear molecule have? - ANSWER- 3N - 5
How many vibrational nodes does a non-linear molecule have? - ANSWER- 3N - 6
What are the types of vibrational modes? (6) - ANSWER- symmetrical stretch, asymmetrical
stretch, wagging, twisting, rocking, scissoring
What is vibrational spectroscopy also known as? - ANSWER- Infra-red spectroscopy
, What happens to the LUMO-HOMO gap when conjugation increases - ANSWER- it decreases
What is the Zeeman effect? - ANSWER- In the absence of a magnetic field the two spin levels
have the same energy
If a magnetic field is applied then the levels split depending on whether the *spin lines up with or
against the magnetic field direction*
Higher shielding causes a higher or lower chemical shift? NMR - ANSWER- lower chemical
shift
How do hydrogen atoms effect shielding? NMR - ANSWER- The more hydrogen atoms on a
carbon the greater the shielding
How do adjacent electronegative atoms effect shielding? NMR - ANSWER- Decreases
shielding
How does unsaturation effect shielding? NMR - ANSWER- Decreases shielding
How do you work out the number of nuclei giving rise to a particular signal? - ANSWER- The
area under the signal is proportional to the number
gives a ratio of H atoms for each peak
What is coupling caused by in C13 NMR? - ANSWER- the H nuclei on the same carbon atom
(the adjacent C is too far away to have an effect)
What is coupling caused by in H NMR? - ANSWER- the H on adjacent C atoms
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller LECTpharis. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $10.99. You're not tied to anything after your purchase.
