Spectroscopy Flashcards

1
Q

Describe the IR absorption of O-H

A

Broad peak around 2900 cm-1 to 3300 cm-1.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Describe the IR absorption of C=O

A

Sharp peak near 1700 cm-1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What does a-state mean in NMR?

A

Lower energy nuclei that are aligned with the B field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What does ß-state mean in NMR?

A

Higher energy nuclei that are aligned opposite the B field

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What’s the H-NMR ppm shift for alkanes?

A

1-3ppm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What’s the H-NMR ppm shift for alkenes?

A

4-7ppm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What’s the H-NMR ppm shift for aldehydes?

A

9-10ppm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What’s the H-NMR ppm shift for carboxylic acids?

A

10-12ppm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What’s the H-NMR ppm shift for aromatic ring?

A

6-8.5ppm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

When do you observe coupling between H’s in H-NMR?

A

When H’s are within 3 bonds of each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Explain UV spectroscopy

A

Wavelength of max absorbance tells us extent of conjugation within conjugated systems. More conjugated = lower E = greater wavelength.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Explain the two important peaks in mass spectrometry

A

The base peak is the highest intensity peak, and the molecular ion (parent ion) peak is the peak with the highest m/z and corresponds to the normal molecule in a cationic form (just +1), the molecular mass = the m/z ration (since z=1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly