Unit 2 Practical Scientific Procedures +Techniques
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Osman Yousuf – Unit 2
Personal Development
Unit 2 entails practical work such as Titrations, Calorimetry, Colorimetry, Cooling Curves, and
Chromatography. Before attempting the Unit 2 practical’s, my skills were very basic. I learnt many
more skills by completing the practical’s, by following the method step by step, ensuring not to miss
out any details, observing at other peer groups to see if their work correlates with mine, and by
listening and noting down instructions from the lecturer. The skills I learnt from Unit 2 are
transferrable to Unit 14 Organic Chemistry practicals, where I acknowledged my own weaknesses
and attempted to improve by drawing on feedback from others, this led to successful practical’s.
These enhanced and valuable skills I have learnt, allows me to prepare and progress to work in future
laboratories with a greater understanding of laboratory equipment, health and safety measures, and
the importance for mature behaviour, and responsibility in laboratories.
My previous skills before introduction to unit 2 included:
The ability to read a thermometer and safely utilise it for practicals.
Knowledge on full personal protective equipment (PPE) and why it is enforced to keep us
safe, or why some practicals may not require full PPE.
The ability to measure out powdered substances, on a top pan balance.
Basic knowledge on health and safety within a laboratory.
Correct use of a Bunsen burner, tripod, and gauze, to heat a substance or liquid such as
deionised water up.
Basic use of results for lab report calculations.
These skills I knew, were transferrable to unit 2, but further enhanced. Therefore, I learnt more skills,
and how to carry them out accurately and independently, as unit 2 went on. These skills included:
Calibration of equipment such as a Pipette, Burette, pH meters, Digital and Spirit
Thermometers, Colorimeters, and Top Pan Balances.
Taring a balance
Carrying out multiple titrations, I learnt to clean the spout of a burette because bubbles in
the spout of a burette or pipette affects volume – leading to error. Learnt to check glassware
for excess water, or checking for any forms of damage, as this makes it inappropriate to use.
I learnt how to identify the neutralisation/end point of a titration using a colour indicator
such as phenolphthalein.
A range of different types of errors, how they are caused, the impact it has on the practical’s
results, calculations, and conclusions, and how to minimise them for future practicals.
Drawing graphs from practical results, and correctly drawing a line/curve of best fit. Drawing
tangents on graphs to calculate rates of reaction for cooling and to identify melting points.
Setting up equipment for a practical.
Calculating Rf values of mixtures, and liquids of substances to identify the components.
Greater understanding of COSHH for creation of risk assessments prior to the practical, and
why this is important in maintenance of health and safety within a laboratory.
There have been many skills which I feel have been greatly improved since my basic skills before the
introduction to unit 2. My skills were mainly improved by repetitive procedures such as calibrations, I
also perform well when the lecturer demonstrates briefly how the practical is appropriately carried
out, the safety measures that need to be followed, and providing an overview of the experiment. For
a range of practical’s, I would ask the lecturer questions. Some of these questions included, why is a
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, Osman Yousuf – Unit 2
primary standard (sodium carbonate) used for this experiment? (For 017) or how to identify when an
acid, in an acid-base titration, has been standardised. Why does a person have to refrain from
touching the centre areas of a TLC plate? (For chromatography).
One of my weaknesses that needs improvement is use of new equipment. When I am introduced to
new equipment, without a demonstration, I struggle to be able to utilise it correctly to carry out the
practical. For example, in chromatography practical’s, a micro-centrifuge/capillary tube was used, in
which I had never used before. Due to the fragility of the tool, it broke on many occasions, and as it is
made of glass, this can be hazardous to surrounding peers in the same work area. I instantly alert
peers, and the lecturer to be aware of my accident, and to ensure their safety. However, I also
received a demonstration from my lecturer on the correct use of a micro-centrifuge tube which
enabled me to gain confidence on use and to continue with the practical. With more practice using
equipment I am unfamiliar with, the further I can improve to reduce my weaknesses, and allow them
to become my strengths.
Another one of my Weaknesses is adding excessive amounts of mixtures, solutions, and liquids on
the starting line of a chromatography plate by using the capillary tubes, this is due to my swiftness at
practicals in which I do not take my time on tasks. When excessive amounts of liquids are placed on
the starting line, it could result in smears, or big spots, this is because a larger volume of liquid is
more difficult to separate. This causes the chromatogram to show many inconsistencies in which the
Rf values are difficult to retrieve and calculate, and therefore having to repeat as it is not up to
standards. I recognise that patience is key into carrying out practicals correctly. For next time, I will
ensure to learn from my mistake by gently using a capillary tube and holding down on the designated
area of the plate until a wet circle forms, I will ensure to wait until the spot has dried before
continuing to add another spot, until a total of 3-4 spots have been placed on the designated area of
the starting line.
One of my strengths is calibration of equipment, especially pipettes, burettes, and a top pan balance.
This is mainly due to repetitive procedures, in which is done at the start of many practicals. Especially
LPN 043, where we had a whole practical to further enhance our knowledge on the correct way to
calibrate. I feel confident that I can independently calibrate equipment, and this is vital to ensure
equipment produces accurate readings to minimise errors.
Feedback from Peers
My peers suggested to me that most of the time I carry out the practical rapidly, and mostly leading
to an overshot end point for titration practical’s. I acknowledge this as a weakness of mine. An
overshot end point is a volumetric/human error which could produce incorrect or inaccurate results,
therefore affecting calculations and conclusions. To improve I know to take my time when carrying
out practical’s, I could improve by having more practice for neutralisation reactions and can achieve
this by ensuring to take part as much as I can or volunteering to do a task. Further improvements
could be to open the stop cock of a burette by the minimum amount to create a drop-wise flow,
when in the proximity of the end point. I will know this by constantly swirling a conical flask when it
receives the liquid from the burette and seeing changes of the colour of the solution in the conical
flask. I will ensure to be constantly observing the burette and the conical flask simultaneously to
know when to stop and obtain correct and accurate titration values.
Skills Developed Compared to my Peers
Maths is also a part of science which is greatly used for calculations. I had learnt maths prior to
starting unit 2 and therefore had good knowledge (which was transferrable) on how to use this for
2
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