Unit 22 – M3 D2 – Applied Science
M3 – explain how the test-tube reactons and infrared spectra allowed the functonal
groups of each substance to be identiede
D2 – evaluate whether the qualitatve analysis carried out was conclusivee
There is a way in which the infra-red spectroscopy and the covalent bonding works, some
molecules are joined by covalent bonding. These molecules tend to naturally vibrate which
tends to increase when the temperature in the compound is increased. This means that due
to the vibratons the molecules in the compounds are constantly moving which makes them
ideal for absorbing infra-red light. The covalent bonds have the ability to absorb the infra-
red light and result with the bonds bending and stretching. So when the infra-red
spectroscopy light is being passed through the compound it would cause the bonds to be
stretched and therefore it would be possible to determine the presence of the types of
bonds and also the elements.
For example, there are single bonds and double bonds which could be identied using the
infra-red spectroscopy. Those peaks which are found afer the wavenumber of 155cm-
are called the ingerprint region of the spectrum. The way in which these ingerprint regions
are used is by either using a sofware which would automatcally determine the compound
or it can be compared by looking at two graphs which one is already a known compound
with all of the peaks already identied and another graph is the one which you’re trying to
ind.
The way in which I determined the characteristc II absorptons for bonds with functonal
groups is by looking at the table below;
By looking at the data which I
had for the diferent samples
for the infra-red spectroscopy, I
found it difcult to determine
straight away in which of the
graphs was for which
compound. However, I
managed to igure what
compound was for which
diagram by looking at the
presence of peaks, how big the
peaks are, how wide the peaks
are and also where exactly on
the graph those peaks are at.
The easiest compound to ind
was the methylpropan- -ol
because from the name straight
away it told me that the
compound was going to be an
M3 – explain how the test-tube reactons and infrared spectra allowed the functonal
groups of each substance to be identiede
D2 – evaluate whether the qualitatve analysis carried out was conclusivee
There is a way in which the infra-red spectroscopy and the covalent bonding works, some
molecules are joined by covalent bonding. These molecules tend to naturally vibrate which
tends to increase when the temperature in the compound is increased. This means that due
to the vibratons the molecules in the compounds are constantly moving which makes them
ideal for absorbing infra-red light. The covalent bonds have the ability to absorb the infra-
red light and result with the bonds bending and stretching. So when the infra-red
spectroscopy light is being passed through the compound it would cause the bonds to be
stretched and therefore it would be possible to determine the presence of the types of
bonds and also the elements.
For example, there are single bonds and double bonds which could be identied using the
infra-red spectroscopy. Those peaks which are found afer the wavenumber of 155cm-
are called the ingerprint region of the spectrum. The way in which these ingerprint regions
are used is by either using a sofware which would automatcally determine the compound
or it can be compared by looking at two graphs which one is already a known compound
with all of the peaks already identied and another graph is the one which you’re trying to
ind.
The way in which I determined the characteristc II absorptons for bonds with functonal
groups is by looking at the table below;
By looking at the data which I
had for the diferent samples
for the infra-red spectroscopy, I
found it difcult to determine
straight away in which of the
graphs was for which
compound. However, I
managed to igure what
compound was for which
diagram by looking at the
presence of peaks, how big the
peaks are, how wide the peaks
are and also where exactly on
the graph those peaks are at.
The easiest compound to ind
was the methylpropan- -ol
because from the name straight
away it told me that the
compound was going to be an
