Module 4

Question 1

what is spectroscopy

Answer 1

the way that a particular chemical interacts with em radiation can tell chemists about its molecules

Question 2

what is a spectroscope

Answer 2

an instrument which allows radiation to interact with a sample of a chemical, then analyses the changes

Question 3

what happens when the energy of the IR is absorbed by a covalent bond

Answer 3

the bond vibrates

Question 4

what are the axis on the absorption spectrum

Answer 4

x- wavenumber

y- transmittance

Question 5

how does an IR spectrometer work

Answer 5

Radiation split into 2 beams.
One beam passes through the sample, which absorbs radiation of certain frequencies as the covalent bonds break.
The other is the reference beam.
Both beams meet in the detector, where the 2 beams are compared and information is sent to the chart recorder.

Question 6

what is each compounds unique IR spectrum called

Answer 6

fingerprint

Question 7

`how to identify particular groups

Answer 7

region of absorption and the broadness or sharpness of the peak

Question 8

uses of IR spectroscopy

Answer 8

breathalysers

monitor gases causing air pollution

Question 9

3 gases absorb IR emitted from the earth’s surface

Answer 9

water vapour
carbon dioxide
methane

Question 10

what does a mass spectrometer measure

Answer 10

separates atoms according to their mass and shows the relative numbers of the different atoms/fragments present

Question 11

what must happen to the atoms before they can be detected by mass spectrometry

Answer 11

must be converted into positively charged ions then separated by deflection

Question 12

why is there a small M+1 peak in mass spectrometry

Answer 12

due to the presence of carbon-13

Question 13

why might there be 3 different peaks for chlorine

Answer 13

isotopes