IR Spec

Question 0

the lighter/less massive the connecting atoms, the:

Answer 0

higher the energy/frequency they will abosrb, the farther to the left they will be.

Question 1

the stronger the bond the

Answer 1

higher the frequency/energy that is absorbed, the farther to the left of the graph it is.

Question 2

the higher the frequency, the higher the wave number, the higher the energy, the shorter the ?

Answer 2

wavelength

Question 3

IR used for:

Answer 3

defining/finding functional groups.

Question 4

The more conjugated the system is (the more pi bonds present), th lower the _______, therefore the lower the _________, and the longer the _________. They will be more to the _______ of the graph.

Answer 4

lower the frequency, the lower the energy, the longer the wavelength. Will be more right on the graph.

Question 5

Alkynes:
terminal wavenumber
non-terminal wavenumber

Answer 5

terminal: 3300, sharp

not terminal: 2150

Question 6

alkenes C=C wave numbers

Answer 6

terminal: 3000 and sharp

not terminal: 1600-1680

Question 7

Normal Degree of Saturation Formula:

Answer 7

((2n+2)-(# of H’s))/2

n= number of carbons:)

Question 8

Degree of Unsaturation when Nitrogen is Present Formula

Answer 8

(2(n+# of N’s)+2)-(# of N’s)-(number of H’s) all divided by two.

Question 9

Degree of Unsaturation if Cl is Present (formula)

Answer 9

(2n+2)-(# of H’s + # of Cl’s) all divided by two:)

Question 10

Ester Peaks?

Answer 10

C=O stretch at 1735-1800

single C-O stretches at 1000-1300.

Question 11

Aldehyde Peaks

Answer 11

C=O stretch at 1715 (strong)

Doublet peak (C-H) at 2810 and 2715

Question 12

Anhydride

Answer 12

2 C=O stretches, 1855 and 1785

2 C-O stretches at 1200

Question 13

Carboxylic Acid

Answer 13

Strong C=O stretch at 1720

Big and broad. kinda squat. “O-H” stretch at 3600-2500

Question 14

Ketone Peaks

Answer 14

C=O stretch at 1725.

an absence of: second carbonyl, C-H doublet as seen in aldehydes, no O-H stretch or C-O stretches (1000-1300)

Question 15

Nitrile Peaks (C triple bond N)

Answer 15

2250

Question 16

Amide

Answer 16

1630-1680

Absorbtion at 1650, which is a combo of the C=O stretch and the N-H bending.

Question 17

Alkane Peaks

Answer 17

Few Simple stretches

C-H stretch at 2800

C-H Bend- 1300

Question 18

Terminal Alkyne

Answer 18

3300 Sharp

Question 19

Not terminal Alkyne

Answer 19

2150

Question 20

Terminal Alkene (C=C-H)

Answer 20

3000. Sharp.

There will be the normal C-H stretch, and it will be the sharp, shorter peak to the left of it.

Question 21

Not Terminal C=C stretch (alkene)

Answer 21

1600-1680

Question 22

Amine Stretch/peaks

Answer 22

N-H

3300-3350

Question 23

Beer Lambert’s Law

Answer 23

A=Ecl or A=Ecb

relates absorbance to concentration.

Question 24

The less conjugated the system, the ____ the light absorbtion.

Answer 24

higher

Question 25

The more conjugated (more pi bonds) a system is, the ______ light it will absorb.

Answer 25

less

Question 26

Bromine Isotopes

Answer 26

79-Br and 81-Br 50/50 81-Br is M2+

Question 27

Chlorine Isotops

Answer 27

35-Cl and 37-Cl 3:1 Ratio the 37-Cl peak will be 1/3 the size of the 33 peak. M2+

Question 28

Gas Chromatography | Stationary Phase and Mobil Phase

Answer 28

Stationary Phase: inside of column coated w/a material w/ a high B.P. Mobile Phase: Gas like Hydrogen or Helium The more the sample interacts w/the stationary phase, the slower it will move through the column. (Dipol-dipol, hydrogen bonding, etc) End Detect: thermal conductivity, flame ionization, mass spec, IR spec