Topic 7 Flashcards
1
Q
What is the molecular ion peak?
A
- Peak furthest to the right
- Greatest mass-to-charge ratio (m/z)
- Result of the organic molecule losing an electron in the machine
2
Q
What is the equation for finding relative molecular mass in mass spec?
A
3
Q
How do find the relative atomic mass from mass spectra?
A
4
Q
How do find the relative atomic mass from mass spectra?
A
5
Q
What does fragmentation allow us to do?
A
- Often used to work out the structure of an organic molecule
- Carbon double bond would break into two species
- Another positive ion
- Neutral species (usually a radical)
6
Q
Use ethane as an example of fragmentation
A
- The molecular ion of ethane $(CH_3-CH_3)^+$ fragments into:
- CH3+ - Methyl Cation
- CH3’ - Methyl Radical
- Since the products are identical you would see a peak at m/z = 15
7
Q
What is Infer-red spectrometry?
A
- Uses IR radiation to determine functional groups present in organic molecules
- Different types of bonds would absorb the radiation in different amounts
- The varying amounts would be measured and recorded allowing for the identification of functional groups
8
Q
What is the fingerprint region?
A
- Located on the right-hand side
- 500-1500 cm-1
- Which contains tiny differences between each species
- Allowing for the molecule to be identified
9
Q
What is the characteristic curve for the -O-H alcohol group?
A
- 3230-3550 cm-1
- A rounded and jagged spike
10
Q
What is the characteristic curve for the -O-H Acid group?
A
- 2500-3300 cm-1
- Smooth Start, jagged end
11
Q
What is the characteristic curve for C=C Unsaturated group?
A
- 1620-1680 cm-1
- Skinny rounded spike
