Organic Lab Spectra Quizzam

Question 1

Molecular fragments that have resonance are found further __________ (downfield or upfield) in NMR.

Answer 1

Downfield

Question 2

An alkane fragment is found further ________ (downfield or upfield) than an alkene in NMR.

Answer 2

Upfield

Question 3

Give an example of a heteroatom.

Answer 3

oxygen

Question 4

What is the splitting pattern expected for a methyl adjacent to a methylene? (Look at the methyl) -CH2CH3

Answer 4

triplet

Question 5

Name a functional group that has a broad peak in both IR and NMR.

Answer 5

Hydrogen bonding

Question 6

What is the range and number of peaks for amines in the IR?

Answer 6

3000-3300 cm-1 and 2 peaks

Question 7

Which peaks in the IR would have higher cm-1 values?triple bonds, double bonds or hydrogen bonds

Answer 7

hydrogen bonds

Question 8

Which peaks are found b/w 2000 and 2400cm-1 in IR?

Answer 8

triple bonds

Question 9

If a NMR peak is a singlet, how many neighboring hydrogens would be present?

Answer 9

0

Question 10

What is the mass spec of Cl?

Answer 10

3 to 1 M+ to M+2

Question 11

What is the mass spec of Br?

Answer 11

1 to 1 M+ to M+2

Question 12

What is the mass spec of I?

Answer 12

large M+

Question 13

What is the mass spec of N?

Answer 13

large M+ and very small M+1

Question 14

What is the observed NMR peak from a cis or trans alkene?

Answer 14

a quartet b/w 5-6 ppm

Question 15

What is the observed NMR peak of a para distributed benzene?

Answer 15

doublet of doublets at 7-8 ppm

Question 16

What is the observed NMR peak of a mono distributed benzene?

Answer 16

a messy singlet at 7-8 ppm

Question 17

What is the observed NMR peak of a methyl attached to a heteroatom?

Answer 17

singlet at 3.5 ppm

Question 18

What is the observed NMR peak of a methyl attached to a carbonyl?

Answer 18

singlet at 2 ppm

Question 19

What is the observed NMR peak of a ethyl group?

Answer 19

a triplet-quartet

Question 20

What is the observed NMR peak of a isopropyl group?

Answer 20

a multiplet doublet

Question 21

What is the observed NMR peak of a n-propyl group?

Answer 21

triplet-multiplet-triplet

Question 22

What is the observed NMR peak of a terminal alkene?

Answer 22

multiplet-doublet of doublets at 5-6 ppm

Question 23

In a C-13 NMR, if a spectrum has the same number of peaks as the number of carbons in the molecular formula, the molecule has symmetry. False/true?

Answer 23

False

Question 24

Organize from lowest to highest in terms of IR.
CH sp3
CH sp
CH sp2
C=O

Answer 24

C=OCH sp3CH sp2CH sp

Question 25

Describe C=O IR peak in IR.

Answer 25

Very large overall peak height in a vertical nature.

Question 26

Why did grignard need to be dry?

Answer 26

Because the water in the grig react to make hydrocarbon and not the product you want.

Question 27

Why did we wash cyclopentadiene with hexane several times?

Answer 27

To completely transfer the cyclopentadiene to the mixture.

Question 28

Why is cyclopentadiene slowly distilled?

Answer 28

To minimize the possibility of bumping occurring during distillation.

Question 29

Why is the claisen head necessary?

Answer 29

Because the dicyclopentadiene will likely bump during distillation. Claisen head acts as a catch for hot liquid from the boiling flask.