Unit 4 - Laboratory Techniques and their Application
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Summary BTEC APPLIED SCIENCE UNIT 4 ASSIGNMENT C: (DISTINCTION)
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Unit 4 - Laboratory Techniques and their Application
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PEARSON (PEARSON)
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Unit 4 - Laboratory Techniques and their Application
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Making Aspirin
Introduction
The process that prepares aspirin can be split into two sections, The preparation of aspirin and
purification of aspirin, the preparation of aspirin includes the composition of all chemicals that
make up the NSAID however it's not at its pure form so therefore the purification of the aspirin
section purifies the compound by crystallizing and then recrystallisation, then after the pure
product left behind can be used to compare with products sold by industries which have a
theoretical purity of 100%.
The purity of the product will be measured using the boiling point method, and therefore
compared with theoretical boiling point to find the percentage yield of the purity of the product
we produced. In addition, other tests will be carried out like chromatography to compare the
product purity compared to known results.
A two-step procedure begins with the distillation of the leaves of a plant called Gaultheria
procunbers to produce oil of wintergreen, which is used to create aspirin (wintergreen).
Approximately 98 percent of the methyl 2-hydroxybenzoate in wintergreen oil is methyl 2-
hydroxybenzoate. It is then hydrolyzed when heated with sodium hydroxide solution. Then the
use of reflux is used to prevent vapors from escaping from the reaction mixture.
Risk Assessment
The use of concentrated sulfuric acid can be harmful as it is corrosive. To decrease the risk of
the chemical affecting one's skin or eye, the apparatus that withholds the chemical must be
handled with care and safety goggles must be worn. In addition to control the gases let in the air
by sulfuric acid a fume cupboard can be used.
Glass apparatus is used so therefore there is a risk of glass shattering and hurting someone,
however this can be controlled if apparatus is handled appropriately and kept away from table
edges.
The use of ethanol could be a risk as it probes a possibility of a fire as it's characterized to be
flammable. In order to control this risk, it's important to keep ethanol away from naked flames
from the Bunsen burner. In order to prevent harm, it is important to wear gloves an googles in
additions it important to handle the substance with care.
During the experiment the use of sodium hydroxide was mandatory. But in addition, it also adds
a risk of one hurting themselves as the substance is very corrosive and can cause serious harm,
in order to prevent harm, it is important to wear gloves an googles in additions it important to
handle the substance with care.
During the experiment a top pan balance is used, this is an electrical appliance, in order to avoid
risk of electrical damage one use be careful when transporting liquids around the appliance and
also be careful what liquids you place.
, Preparation of aspirin
-Stage A: Preparation of 2-hydroxybenzoic acid
Equipment
• eye protection
• a balance
• 10cm 3 measuring cylinder
• 50cm 3 measuring cylinder
• 50cm 3 pear-shaped flask
• reflux condenser and tubing
• Clamp and stand
• anti-bumping granules
• water bath or Bunsen burner
• 100cm 3 beaker
• larger beaker to contain ice and water to cool the mixture
• blue litmus paper
• distilled/de-ionized water
• dropper pipette
• stirring rod
• Buchner or Hirsch funnel, flask and filter paper, and suction equipment
• watch glass
• sample tube and lid
• Oil of wintergreen
• sodium hydroxide solution, 2 mol dm - 3
• concentrated hydrochloric acid
Method
1. Using a 50 cm3 pear-shaped flask and a reflux condenser, set up the apparatus for reflux
2. Fill a 10 cm3 measuring cylinder with around 2.5 cm3 of wintergreen oil and weigh it.
3. Fill the pear-shaped flask halfway with wintergreen oil.
4. Calculate the mass of oil of wintergreen added to the pear-shaped flask by recording the
mass of the measuring cylinder once again.
5. Measure around 25 cm3 of 2 mol dm-3 sodium hydroxide solution in a 50 cm measuring
cylinder and pour it into the pear-shaped flask.
6. Fill the flask with anti-bumping grains.
7. For around 30 minutes, heat the reaction mixture on a Bunsen burner.
8. Allow the mixture to cool before pouring it into a 100 cm 3 beaker that is being cooled in
a larger beaker of ice and water.
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