Mass spectrometry

Question 1

IR Spectroscopy

Answer 1

The study of the interaction between matter & electromagnetic radiation (IR spectroscopy)

Question 2

Mass spectrometry

Answer 2

The study of the interaction between matter & an energy source other than electromagnetic radiation

Question 3

__________ is used to determine the molecular weight & molecular formula of a compound

Answer 3

Mass spectrometry

Question 4

In __________ a compound is embarded with electrons to produce a radical cation

Answer 4

Mass spectrometry

Question 5

The mass of the radical cation is the same as the mass of the _________

Answer 5

Original compound

Question 6

The radical cation is symbolized by (M)^+* is called ___________ it is also unstable & goes through fragmentation, which generates two distinct fragments (usually one fragment carries the unpaired electron & the other carries the charge)

Answer 6

Molecular ion (or parent ion)

Question 7

Only the _________ & _________ are detected by mass spectrometry

Answer 7

Molecular ion & cation fragment

Question 8

Smaller ions are deflected ________ than larger ions & ions which multiple charges are deflected more than ions with charge of +1

Answer 8

More

Question 9

Cations are separated by their ___________ where z is +1 so m/z just measures the mass & a mass spectrum is generated to show the amount of each cation detected

Answer 9

Mass-to-charge ratio (m/z)

Question 10

For _________ the molecular ion is the base peak (most abundant) at 16 m/z

Answer 10

methane

Question 11

___________ of methane involves loss of hydrogens & all the other peaks below 16 is the result of the loss of a hydrogen or more than 1 H

Answer 11

Fragmentation

Question 12

When analyzing a mass spectrum, the 1st step is to look for the _______ peak because it indicated the molecular weight of the molecule

Answer 12

(M)^+* - the molecular/parent ion peak

Question 13

An ________ molecular weight generally means an odd number of nitrogen atoms in the compound

Answer 13

Odd

Question 14

An ________ molecular weight generally means an even number of nitrogen atoms in the compound, or a nitrogen atom is missing

Answer 14

Even

Question 15

______ of carbon is ¹²C, 1.1% is ¹³C & 0.000001% is ¹⁴C

Answer 15

98.9%

Question 16

The ________ represents the ¹³C atom & its overall 1.1% the height of the molecular ion

Answer 16

(M+1)^+*

Question 17

The more carbons you have the more _____ you have

Answer 17

¹³C (ex. decane has 11% ¹³C because 10 x 1.1% = 11%)

Question 18

Chlorine has two major isotopes _______ & _______

Answer 18

³⁵Cl - 75.8% & ³⁷Cl - 24.2%

Question 19

Compounds that contain _________ atoms will have a strong (M+2)^+* peak

Answer 19

Chlorine

Question 20

Bromine has two isotopes ______ & ______ & they are both equally abundant so a compound containing Br will have a peak at (M+2)^+*basically the same height as the molecular ion peak

Answer 20

⁷⁹Br - 50.7% &⁸¹Br - 49.3%

Question 21

The presence of _______ or _______ in a compound is easily identified by analyzing the height of the (M+2)^+* peak & comparing the height with the (M)^+* peaks

Answer 21

Chlorine or Bromine

Question 22

The majority of the peaks in mass spectrum is produced from ________ of the molecular ion

Answer 22

Fragmentation

Question 23

Fragmentation will occur in all possible locations but will typically favor the most _____ carbocation

Answer 23

Stable

Question 24

What are the two types of fragmentation alcohols go through?

Answer 24

1. Alpha Cleavage
2. Dehydration

Question 25

During _________ a bond to the alpha position of the alcohol is cleaved to form a resonance - stabilized cation & a radical

Answer 25

Alpha Cleavage

Question 26

Alcohol undergo dehydration via loss of a _________ molecule

Answer 26

Water

Question 27

Amines also undergo ________ to generate a resonance - stabilized cation & a radical

Answer 27

Alpha Cleavage

Question 28

Aldehydes & ketones containing a hydrogen at the gamma position generally undergo a __________ rearrangement, which results on the loss of a neutral alkene fragment

Answer 28

Mclafferty rearrangement