Exam 1- Lecture 11

Question 1

What is the larmor equation

Answer 1

w0=v*B0
omega is angular frequency of precession for protons
Gamma is the proportionality constant
B is the strength of applied magnetic field

Question 2

Why is the x axis in ppm

Answer 2

Because it is in delta scale
it is the energy axis
depends on energy difference between alpha and beta states

Question 3

What is shielding

Answer 3

when hydrogen is bonded to carbon the proton is shielded by electrons

Question 4

The higher the electron density around the nucleus the ___ the shielding

Answer 4

greater

Question 5

If the shielding is higher the

Answer 5

there is a chemical shift to the right

Question 6

If the shielding decreases,

Answer 6

there is a chemical shift to the left

Question 7

The higher the electron density to ____ the nucleus feels the magnetic field

Answer 7

Less

Question 8

The lower the electron density the ____ it is exposed to the magnetic field and the ____ energy it absorbs

Answer 8

more, more

Question 9

What is the y axis in NMR spectroscopy

Answer 9

intensity scale
proportional to the number of H nuclei in molecule with same chemical shift

Question 10

What does chemical shift mean

Answer 10

frequency of absorption for a nucleus to the frequency of absorpotion of a molecular standard

Question 11

What is the N+1 rule

Answer 11

will determine the number of peaks in the NMR spectrum for a specific functional group
N
is the number of directly attached 1
Hs on the neighboring carbon