✅7 - Modern Analytical Techniques I Flashcards

1
Q

What is mass spectrometry used for?

A

Identifying compounds

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2
Q

What is the molecular ion, M+?

A

The molecule with an electron removed

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3
Q

What is the molecular ion peak?

A

The peak with the highest m/z value

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4
Q

What does the Molecule ion peak show?

A

The relative formula mass of the compound

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5
Q

What can the molecular ion be broken into?

A

Smaller fragments

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6
Q

What is a fragmentation pattern?

A

The mass spectrum shown by all the fragments

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7
Q

How can fragments be identified?

A

By their molecular mass

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8
Q

What is mass spectrometry used to differentiate between?

A

Similar molecules

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9
Q

How is Infrared spectroscopy carried out?

A

A beam of IR radiation is passed through a sample fo a chemical

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10
Q

How does the IR radiation affect bonds?

A

It is absorbed by covalent bonds in the molecules, increasing their vibrational energy

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11
Q

How can IR spectroscopy be used to differentiate between bonds?

A

Bonds between differnet atoms absorb different frequencies of IR radiation

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12
Q

How does the location of a bond affect its absorption?

A

In the frequency absorbed, so OH groups on alcohols and carboxylic acids have different frequencies of absorption

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13
Q

What does in infrared spectrometer produce?

A

A graph

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14
Q

What is plotted on the y axis of an IR graph?

A

Transmittance

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15
Q

What is plotted on the x axis of an IR graph

A

Wavenumber - 1/wavelength in cm

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16
Q

How can IR spectroscopy show if a reaction has happened?

A

If the functional group has changed on the graph

17
Q

How would an IR spectroscopy graph change if an alcohol was oxidised to an aldehyde?

A

The O-H absorption would disappear and and C=O would appear

18
Q

How would an IR spectroscopy graph change is an aldehyde was oxidised to a carboxylic acid?

A

The O-H peak would appear at a slightly lower frequency and the C=O peak will remain

19
Q

What does IR radiation cause covalent bonds to do?

A

Vibrate

20
Q

What do the peaks on the IR graph show you?

A

Where the radiation is being absorbed