Organic II - NMR Spectroscopy

Question 1

How many 1H NMR signals does a benzene ring have?

Answer 1

1

Question 2

How many 1H NMR signals does pentane have?

Answer 2

3

Question 3

Chemical shift is measured in ____.

Answer 3

ppm

Question 4

Upfield is _____ on the graph and downfield is _____ on the graph.

Answer 4

right; left

Question 5

Upfield has ________ (higher or lower) d

Answer 5

lower

Question 6

Downfield has _________ (higher/lower) d

Answer 6

higher

Question 7

What describes the directions on the scale?

Answer 7

Upfield and downfield.

Question 8

What describes the position of a peak on the ppm scale?

Answer 8

Shielded and deshielded.

Question 9

Shielded is = to ______.

Answer 9

upfield

Question 10

Deshielded is = ________.

Answer 10

downfield

Question 11

Protons that are attached to doubly bonded carbons are _________ (___ ppm).

Answer 11

deshielded (5-7)

Question 12

Protons attached to triply bonded carbon atoms are _____ shielded (___ ppm)

Answer 12

less; 2

Question 13

Protons attached to a benzene ring are _________ and appear at about __ ppm.

Answer 13

deshielded; 7

Question 14

Protons that are more shielded absorb at a _________ field.

Answer 14

higher

Question 15

The more electronegative atom of a molecule ________ the protons.

Answer 15

deshields

Question 16

The location of signals show what?

Answer 16

how shielded or deshielded the proton is.

Question 17

The number of signals show what?

Answer 17

How many different kinds of protons are present.

Question 18

The intensity of the signal show what?

Answer 18

The number of protons of that type.

Question 19

Signal splitting shows what?

Answer 19

The number of protons on adjacent atoms.

Question 20

An ethyl group will contain what kind of signal splitting?

Answer 20

Upfield triplet and downfield quartet.

Question 21

A singlet has how many neighboring protons?

Answer 21

0

Question 22

NMR spec of isopropyl is what?

Answer 22

Upfield doublet and downfield septet.

Question 23

In spin-spin splitting, do equivalent protons split each other?

Answer 23

No.

Question 24

Is the splitting of CH2 from CH3(CH2)CH2Br a sextet? Why?

Answer 24

No because the neighboring protons are unequivalent… multiplet.

Question 25

Coupling constants of cis alkene is?

Answer 25

10 Hz

Question 26

Coupling constants of trans alkene is?

Answer 26

15 Hz

Question 27

Coupling constants of geminal alkene is?

Answer 27

2 Hz

Question 28

Coupling constants of ortho protons (besides each other) is?

Answer 28

8 Hz

Question 29

Coupling constants of meta protons (space b/w p+) is?

Answer 29

2 Hz

Question 30

In 13C NMR CH is = to _____.

Answer 30

doublet

Question 31

In 13C NMR CH3 is = to _____.

Answer 31

quartet

Question 32

In 13C NMR CH2 is = to _____.

Answer 32

triplet

Question 33

In 13C NMR C is = to _____.

Answer 33

singlet

Question 34

In 13C NMR, the number of different signals indicate what?

Answer 34

The number of different kinds of carbons.

Question 35

In 13C NMR, the splitting pattern indicate what?

Answer 35

The number of protons attached to the carbon.

Question 36

Does DEPT provide the same info as off-resonance decoupling?

Answer 36

yes

Question 37

DEPT-90 have signals for only ______.

Answer 37

methine (CH) carbons

Question 38

What has a negative peak in DEPT-135?

Answer 38

CH2 groups.