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Title: BTEC Applied Science Unit 22 Assignment 1
Description: Unit 22 : Chemical Laboratory Techniques – Assignment 1 Analytical Techniques Task 1 You have been instructed by your line manager to demonstrate practical skills you must carry out the given procedures to make and extract compounds, hydrated copper(II) sulphate, aspirin, rock salt, paracetamol – see sheets for methods, and record your data precisely and professionally. You must also determine the percentage yield for all compounds made and extracted and carry out procedures to determine the percentage purity of the hydrated copper(II) sulfate and aspirin made. Your line manager has also given you an extra task to test your knowledge and wants you to determine the atom economy for the hydrated copper(II) sulfate and aspirin made. This provides evidence for P1 & P2 Task 2 You have been asked to produce a report so that new or visiting employees in the lab can understand the science behind the practical’s you are completing. The report must outline the key scientific principles behind the methods used in task 1 – preparation of hydrated copper(II) sulphate, aspirin, rock salt and paracetamol and also describe the problems with the methods used so that future employees can improve on the methodologies. This provides evidence for M1 and M2 Task 3 Your faculty director is impressed with the work you have completed and has asked you to research and produce a presentation on how the methods could be changed to improve the yield and purity of all of the compounds made and extracted in task 1. You will be presenting your report via powerpoint and the faculty director has asked for a printed copy the slides you will use. Within your slides you must find another way of making hydrated copper (II) sulfate and another way of making aspirin. Determine the atom economies for these new methods and compare them with the atom economies for the processes you used. This provides evidence for D1 Exam board is Pearson ALL ASSIGNMENTS I HAVE UPLOADED ARE DISTINCTION GRADED.
Description: Unit 22 : Chemical Laboratory Techniques – Assignment 1 Analytical Techniques Task 1 You have been instructed by your line manager to demonstrate practical skills you must carry out the given procedures to make and extract compounds, hydrated copper(II) sulphate, aspirin, rock salt, paracetamol – see sheets for methods, and record your data precisely and professionally. You must also determine the percentage yield for all compounds made and extracted and carry out procedures to determine the percentage purity of the hydrated copper(II) sulfate and aspirin made. Your line manager has also given you an extra task to test your knowledge and wants you to determine the atom economy for the hydrated copper(II) sulfate and aspirin made. This provides evidence for P1 & P2 Task 2 You have been asked to produce a report so that new or visiting employees in the lab can understand the science behind the practical’s you are completing. The report must outline the key scientific principles behind the methods used in task 1 – preparation of hydrated copper(II) sulphate, aspirin, rock salt and paracetamol and also describe the problems with the methods used so that future employees can improve on the methodologies. This provides evidence for M1 and M2 Task 3 Your faculty director is impressed with the work you have completed and has asked you to research and produce a presentation on how the methods could be changed to improve the yield and purity of all of the compounds made and extracted in task 1. You will be presenting your report via powerpoint and the faculty director has asked for a printed copy the slides you will use. Within your slides you must find another way of making hydrated copper (II) sulfate and another way of making aspirin. Determine the atom economies for these new methods and compare them with the atom economies for the processes you used. This provides evidence for D1 Exam board is Pearson ALL ASSIGNMENTS I HAVE UPLOADED ARE DISTINCTION GRADED.
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Unit 22 – Assignment 1 – P1 & P2
Results
Mass of filter paper: 1
...
99g
Mass of dried crystals of product: 2
...
05
N of CuSO4 = 0
...
05 * 159
...
975g
Percentage yield = (actual / theoretical) x 100
= (2
...
975) x 100
= 31%
Calculating the percentage purity of hydrated copper(II) sulfate:
1
...
3
...
5
...
1 x 12
...
00124
0
...
0062
0
...
2232
(0
...
32%
Percentage yield = (actual yield/theoretical yield) x 100
Theoretical = n = mass/mr = 2/138 = 0
...
0145 x 180 = 2
...
161/2
...
36 x 100 = 236%
Percentage mass = (overall weight / mass of two tablets) x 100
= (0
...
543) x 100
= 11
...
Firstly, the solution is heated in an evaporating basin;
therefore allowing the solvent to evaporate, which leaves a saturated solution
...
The crystals are then collected and dried
...
Filtration - Passing a solid and liquid mixture through filter paper gets rid of the solvent and allows
excess solvent to evaporate
...
The fine, porous material of the filter
paper does not allow the solid, insoluble particles to go through
...
Determining the percentage purity of aspirin:
Titration – To determine the volume that has been consumed when the endpoint (the point at which
the titration is complete) is reached, a calibrated burette must be used to add the titrant
...
It is also when
the solution permanently changes colour; this is due to an indicator
...
This point is identified from the first faint pink colour that persists in
the solution being titrated
...
There is a
slight difference between the change in indicator colour and the actual equivalence point of the
titration
...
It leaves the solid residue behind
...
It isolated the
product
...
Drying – This is carried out to remove water from a compound
...
A desiccator
can also be used to absorb any moisture and keeping the product dry, from the evaporated solvent,
from the surrounding air
...
This is either
done by converting the substance into an insoluble form or by changing the composition of the
solvent to decrease the solubility of the substance in it
...
This causes the purity to decrease
whilst causing the analysis to be inaccurate
...
An effective technique
is that called homogeneous precipitation, in which the precipitating agent is synthesized in the
solution instead of adding mechanically
...
It leaves the solid residue behind
...
It isolated the product
...
Firstly, the solution is heated in an evaporating basin;
therefore allowing the solvent to evaporate, which leaves a saturated solution
...
The crystals are then collected and dried
...
Evaporation - Evaporation is used to separate a soluble solid from a liquid
...
During evaporation, the water evaporates away leaving solid crystals
behind
...
Then the
volume of the solution would be decreased
...
Once the water has been evaporated, the solid crystals
are left behind
...
It leaves the solid residue behind
...
It isolates the product
...
Crystallisation is normally
done from a hot concentrated solution
...
The solid crystals will become bigger, as the solution is too
concentrated for the solute to remain dissolved at the temperature
...
When cooling the hot,
concentrated solution, more crystals form
...
Re-crystallisation – Reactions will often yield impure products which need to be purified by recrystallisation
...
The technique of re-crystallisation dissolving the product in
the minimum amount of a hot solvent, hot filtration to remove any insoluble impurities and then
allowing crystals of the purified product to form
...
Firstly, the hot solvent is added to the compound
...
Then, the solution is
filtered while is it hot through a warmed filter funnel
...
As
the temperature of the solution decreases, the solubility of the compound also decreases
...
the
compound can then be collected by filtration and dried
...
If the glassware was not
washed or dried properly and there was leftover solution, it would contaminate and dilute the
solution causing the recordings to be inaccurate, invalid and unreliable
...
This means that you will get an accurate
reading and therefore reduce the error
...
So when adding the sulfuric acid to the measuring cylinder, the bottom of the meniscus must
be on the line
...
This would cause the recordings to be
inaccurate and the experiment to be invalid and unreliable
...
Whilst you are doing this, look at the cylinder at eye-level so you can be sure that you
have added the right amount, once the bottom of the meniscus has fallen on the line
...
Furthermore, an error can also be caused by the misjudgement of the amount of liquid evaporated
on a hotplate
...
If no
crystals were to form, the experiment would not be complete, as you will not be able to work out
the percentage yield of the product
...
To
improve the method before putting the filtrate on the hotplate, pour it into a measuring cylinder
and note the volume down
...
If not, pour it back into the evaporating basin and onto the hot plate and
check the volume again when you think it has reduced enough
...
This means that you will minimise the
error and therefore get a higher percentage yield
...
This means that the recorded mass of the crystals would be less than the actual mass of
the crystals
...
This would cause the recorded percentage yield to be inaccurate
...
By doing this, you can ensure that your
percentage yield would be as high as you can make it
...
Determining the percentage purity of hydrated copper(II) sulfate:
During the titration, one can misjudge the colour of the indicator near the end point - this is the
most common error during this procedure
...
To reduce the percentage
error, a number of people should observe the colour and then come to a final result
...
Another error in the titration could be misreading the volume due to parallax error; this is when
someone reads the volume looking at an angle
...
Parallax error is when we misinterpret a value when measuring something, not looking at it at eyelevel
...
To improve the method, when reading the level at which the meniscus fall on, ensure
that you are looking at the burette at eye level
...
When using solutions of the wrong concentration the titrant used may have a different
concentration
...
To reduce
these errors, record the concentration correctly so that it does not affects the later results
...
Do not keep the
titrant for too long and make sure the solution should be kept where it belongs and is fully sealed so
no water is evaporated
...
If all the
solids and liquids are not fully transferred, for example part of the solid was left in the funnel during
transferring it into the flask or it was lost
...
In addition, if the pipette is not clean, come of the solution
would be left inside in the glass in the form of droplets
...
Preparation of aspirin:
Also, when transferring the crystals from the filter paper used in the suction filtration, to the preweighed filter paper there would be a loss of product, as some would still be on the previously used
filter paper
...
Therefore, the using this mass, the calculated percentage yield would be less than the
actual yield that was made
...
To
improve the method, when transferring the crystals from the filter paper used in the suction
filtration, to the pre-weighed filter paper, use a spatula and maybe a few drops of water to ensure
that you scrape and rinse off as many crystals as possibly
...
This means that you will minimise the error
and therefore get a higher percentage yield
...
This would cause the ratio of the liquids added to the
flask to be inaccurate
...
If no crystals were to form, the
experiment would not be complete, as you will not be able to work out the percentage yield of the
product
...
To improve the method, add a
certain amount of drops to the flask (for example, 4), note it down then add the same number again
until you have added 16 drops in total to the flask
...
This means that you will minimise the error
and therefore get a higher percentage yield
...
This could be caused by parallax error
when pouring ethanoic anhydride up to the 4cm3 line on the measuring cylinder
...
So when
adding the ethanoic anhydride to the measuring cylinder, the bottom of the meniscus must be on
the line
...
This would cause the
recordings to be inaccurate and the experiment to be invalid and unreliable
...
Whilst you are doing this, look at the measuring cylinder at eyelevel so you can be sure that you have added the right amount, once the bottom of the meniscus has
fallen on the line
...
If you increase the temperature too fast, then you may not record the right temperature at which
the substance melts
...
The melting point may be much lower than what it recorded
...
An
improvement to this method would be to very slowly, increase the temperature in intervals
...
As soon as it starts to melt, wait
a bit
...
When it has fully
melted, record the temperature at which it melts
...
Then, compare your melting point to the data book
value melting point for aspirin
...
Be sure not to apply too much pressure as it may break and you may find
some glass in your product
...
5cm), carefully place the tube in the melting point apparatus
...
An alternate method for this is to use a Thiele tube,
thermometer and a Bunsen burner, instead of the melting point apparatus
...
It is a glass tube with an attached
'handle'
...
Firstly, oil is poured into the tube
and the 'handle' is heated
...
The shape of the Thiele tube
allows for formation of convection currents in the oil when it is heated
...
The side arm of the tube
generates these convection currents
...
The sample, packed in a capillary tube, is attached to the
thermometer
...
The tube
is heated; the temperature at which the aspirin melts can be recorded
...
You do not have to
keep increasing the temperature each time
...
Determining the percentage purity of aspirin:
An error could occur when transferring the aspirin
...
This would cause the results to be invalid and unreliable
...
Also use a spatula to scrape it off the sides of the boat, if necessary
...
Also, when measuring the weight of the aspirin, some could get on the top pan balance instead of in
the weighing boat
...
Also, when transferring the
aspirin from the weighing boat to the volumetric flask, someone may breathe on it and mass would
be lost
...
This would cause the results to be
invalid and unreliable
...
If some of
the aspirin goes on the top pan balance, start this step again
...
This means that you will get an accurate reading and therefore reduce the error
...
This could be caused by parallax error when
pouring ethanol up to the mark of the volumetric flask
...
So when adding the ethanol to the
volumetric flask, the bottom of the meniscus must be on the line
...
This would cause the recordings to be inaccurate and the experiment to be
invalid and unreliable
...
Whilst you are doing this,
look at the flask at eye-level so you can be sure that you have added the right amount, once the
bottom of the meniscus has fallen on the line
...
Furthermore, errors could occur by contamination of the solution, or dilution with water
...
To improve
the method, make sure the glassware is clean and has no liquid in it
...
Isolating sodium chloride from rock salt:
When measuring the weight of the salt, some could get on the top pan balance instead of in the
weighing boat
...
This would cause the calculations to be
inaccurate
...
To improve the method, put
the weighing boat on the top pan balance, press the reset button, then add little amounts of salt
with a spatula into the weighing boat
...
This means that you will get an accurate reading and therefore reduce the error
...
Whilst evaporating the filtrate on the hotplate, if you do not evaporate enough of the
volume, then the filtrate would not be at the correct concentration for crystallisation to occur
...
This would cause the recording to be incomplete and invalid
...
Then while the filtrate is being evaporated on the hot plate, when you
think that the volume has been reduced by half, pour it back into the measuring cylinder and see if
the volume has halved
...
By doing this, you can ensure that
the filtrate is at the right concentration for crystals to form
...
Also, when transferring the sodium chloride from the filter paper used in the suction filtration, to the
pre-weighed filter paper there would be a loss of product, as some would still be on the previously
used filter paper
...
Therefore, the using this mass, the calculated percentage yield
would be less than the actual yield that was made
...
To improve the method, when transferring the sodium chloride from the filter
paper used in the suction filtration, to the pre-weighed filter paper, use a spatula and maybe a few
drops of water to ensure that you scrape and rinse off as many crystals as possibly
...
This means that you
will minimise the error and therefore get a higher percentage yield
...
At this point, if it is still being heated, the salt
would spit out of the beaker causing the mass of salt to be less than the noted mass
...
Also, is the hotplate was set at a temperature
that was too high, then it may cause the solution to boil and even overflow out of the beaker
...
To ensure that this does not happen,
keep an eye on the solution and the beaker off the heat, as soon as you can see that the salt has
dissolved in the water
...
The extraction and purification of paracetamol from tablets:
Crystallisation - A factor which can influence the purity of the final product, within this method of
separation can be due to the solution not stirred thoughrally for long enough
...
This means that more solute would
still be dissolved in the solvent
...
This means that the
aspirin would be less pure and there would be less of it
...
This method can also be improved by adding ice cubes to
cool the liquid down at a faster rate
...
The thorough carry out of
this method would increase the number of impurities that are found, causing the aspirin purity to
increase
...
This means that the
filtering would be less effective and some solvent would be left behind, thus causing the aspirin to
be more impure
...
Also, if the funnel
is not pushed down for long enough, then there would be more solvent left behind with the solid
...
This would cause the aspirin purity to
increase, as there would be less impurities within the substance
...
Also, if the product if not left in the fume cupboard long enough, then there
would still be some solvent left behind with the aspirin
...
This method can be improved by leaving
the product in the fume cupboard for longer, possibly a few more days for the solvent to evaporate
...
Within
the box should be desiccant silica gel
...
This can be used to absorb the solvent which evaporates from the substance, so that it will not
condense and fall back into the substance
...
Desiccators
are sealable enclosures containing desiccants, used for preserving moisture-sensitive items
...
It also requires some time to achieve a low humidity
...
Alternate methods
Aspirin
Reference: https://chemicalparadigms
...
com/file/view/Making+Aspirin
...
"Place around 3 grams of salicylic acid in a 125-mL Erlenmeyer flask
...
2
...
3
...
4
...
5
...
6
...
7
...
8
...
"
Reference: https://chemicalparadigms
...
com/file/view/Making+Aspirin
...
5 M, 20 cm3
Copper(II) oxide about 1 g
Eye protection
Each working group will require:
Glass beaker (100 cm3)
Conical flask (100 cm3)
Spatula
Glass stirring rod
Filter funnel
Filter paper
Bunsen burner, tripod and gauze
Heat resistant mat
pH or litmus paper"
Method:
Stage 1
1
...
5 M sulfuric acid to the 100 cm3 beaker
...
2
...
Stir the mixture gently for up to half a minute after each
addition
...
When all the copper(II) oxide has been added, continue to heat gently for 1 to 2 minutes to
ensure reaction is complete
...
It may be wise to check
(using pH or litmus paper) that no acid remains
...
If someone should decide to attempt to evaporate the
acid after filtering, the lab would fill with fumes
...
Allow the beaker to cool slightly while you set up Stage 2
...
2
...
4
...
Fold the filter paper to fit the filter funnel, and put it in the funnel
...
The contents should still be hot
...
Allow to
filter through
...
A clear blue solution should collect in the flask
...
Stage 3 (optional)
1
...
Label the beaker with your
name(s)
...
This will enable most of the water to evaporate
...
Before all the water has evaporated, you should find some crystals forming on the bottom of
the beaker
...
Collect the crystals from the filter paper onto a paper towel
...
rsc
...
wikispaces
...
% atom economy = (Mass of desired product from equation / Total mass of product from equation) x
100
C7H6O3 + C4H6 O3 → C9H8O4 + C2H4O2
C9H8O4:
C9 = 12 * 9 = 108
H8 = 8 * 1 = 8
O4 = 16 * 4 = 64
C2H4O2:
C2 = 12 * 2 = 24
H4 = 4 * 1 = 4
O2 = 16 * 2 = 32
(C9H8O4 / C9H8O4 + C2H4O2) * 100
= (180 / 240) * 100
= 75%
Alternate aspirin method atom economy:
Reference: https://chemicalparadigms
...
com/file/view/Making+Aspirin
...
4 * 1 = 35
...
4) * 100
= 83
...
18%
...
5 * 1 = 63
...
5 * 1 = 63
...
1 * 1 = 32
...
1 * 1 = 32
...
6 / 177
...
5 * 1 = 63
...
1 * 1 = 32
...
1 * 1 = 32
...
5 * 1 = 63
...
6 / 221
...
1%
If you use the alternate method, you will get a difference of approximately 19
...
Title: BTEC Applied Science Unit 22 Assignment 1
Description: Unit 22 : Chemical Laboratory Techniques – Assignment 1 Analytical Techniques Task 1 You have been instructed by your line manager to demonstrate practical skills you must carry out the given procedures to make and extract compounds, hydrated copper(II) sulphate, aspirin, rock salt, paracetamol – see sheets for methods, and record your data precisely and professionally. You must also determine the percentage yield for all compounds made and extracted and carry out procedures to determine the percentage purity of the hydrated copper(II) sulfate and aspirin made. Your line manager has also given you an extra task to test your knowledge and wants you to determine the atom economy for the hydrated copper(II) sulfate and aspirin made. This provides evidence for P1 & P2 Task 2 You have been asked to produce a report so that new or visiting employees in the lab can understand the science behind the practical’s you are completing. The report must outline the key scientific principles behind the methods used in task 1 – preparation of hydrated copper(II) sulphate, aspirin, rock salt and paracetamol and also describe the problems with the methods used so that future employees can improve on the methodologies. This provides evidence for M1 and M2 Task 3 Your faculty director is impressed with the work you have completed and has asked you to research and produce a presentation on how the methods could be changed to improve the yield and purity of all of the compounds made and extracted in task 1. You will be presenting your report via powerpoint and the faculty director has asked for a printed copy the slides you will use. Within your slides you must find another way of making hydrated copper (II) sulfate and another way of making aspirin. Determine the atom economies for these new methods and compare them with the atom economies for the processes you used. This provides evidence for D1 Exam board is Pearson ALL ASSIGNMENTS I HAVE UPLOADED ARE DISTINCTION GRADED.
Description: Unit 22 : Chemical Laboratory Techniques – Assignment 1 Analytical Techniques Task 1 You have been instructed by your line manager to demonstrate practical skills you must carry out the given procedures to make and extract compounds, hydrated copper(II) sulphate, aspirin, rock salt, paracetamol – see sheets for methods, and record your data precisely and professionally. You must also determine the percentage yield for all compounds made and extracted and carry out procedures to determine the percentage purity of the hydrated copper(II) sulfate and aspirin made. Your line manager has also given you an extra task to test your knowledge and wants you to determine the atom economy for the hydrated copper(II) sulfate and aspirin made. This provides evidence for P1 & P2 Task 2 You have been asked to produce a report so that new or visiting employees in the lab can understand the science behind the practical’s you are completing. The report must outline the key scientific principles behind the methods used in task 1 – preparation of hydrated copper(II) sulphate, aspirin, rock salt and paracetamol and also describe the problems with the methods used so that future employees can improve on the methodologies. This provides evidence for M1 and M2 Task 3 Your faculty director is impressed with the work you have completed and has asked you to research and produce a presentation on how the methods could be changed to improve the yield and purity of all of the compounds made and extracted in task 1. You will be presenting your report via powerpoint and the faculty director has asked for a printed copy the slides you will use. Within your slides you must find another way of making hydrated copper (II) sulfate and another way of making aspirin. Determine the atom economies for these new methods and compare them with the atom economies for the processes you used. This provides evidence for D1 Exam board is Pearson ALL ASSIGNMENTS I HAVE UPLOADED ARE DISTINCTION GRADED.