Unit 2- Practical Scientific Procedures and Techniques
Institution
PEARSON (PEARSON)
This is coursework for Unit 2 Practical Scientific procedures and techniques and is Learning aim D - Reflection on practical work for Titration, Calorimetry and Chromatography. Work is at a DISTINCTION standard. Good luck with writing!
Unit 2- Practical Scientific Procedures and Techniques
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Unit 2 – Outcome D: Reflection
Introduction
In this report I will evaluate my performance and the skills I have developed during the experiments of
titration, cooling curves and chromatography. I will look at what skills and abilities I had before I
undertook the experiments and will observe what new useful skills I have developed throughout. I will
discuss my strengths and weaknesses during each practical and where improvements could be made in
my techniques. Throughout the unit, I have learnt and applied many new skills in the experiments, and
this will also be useful for me during the continuation of my course in unit 3 where these skills can be
transferred.
Titration
Key skills gained from titration
During the titration, I had learnt many new skills. One of them being calibration. Before undertaking the
titration experiment, I had never calibrated equipment before. I learnt that this will a crucial part of the
experiment as it allowed me to check if the equipment was working properly and this would allow
accurate results to be produced. Calibration allowed us to detect any disturbances in the laboratory
equipment because we could check if the calibrated tool and the verified reference standard are the
same value. If there is a difference, then we can identify a cause and prevent inaccuracies and
interferences during the experiment. At first calibration was slightly tricky for me as I had to try to
calibrate the tool to an exact number so it would be precise and accurate, however once practicing this,
it became easier.
A skill I have learned while preparing standard solutions for the titration was weighing products to the
full gram using a balance that was accurate to three decimal places. Previously in secondary school, I
had only used a basic balance so this skill took a lot of time and patience to develop. When weighing the
sodium carbonate, because it was in powder form, it was very hard to get it to a full gram. This meant I
had to be extra cautious and use a spatula to slightly add small amounts of the sodium carbonate at a
time to get a reading between one or two grams of the required amount. Then I would tap the spatula
to add fraction a fraction of a gram at a time until I had reached the correct amount. This type of skill is
was very helpful for me as it guaranteed accuracy in my result and would be useful for me in future
experiments. Whilst developing this skill, I also realised the importance of surroundings affecting the
experiment. For example, someone walking past or leaning on the work desk could alter the balance
reading as it is sensitive and this would affect the accuracy of our experiment.
Another skill I have learnt is the accuracy of pipettes and burettes. In secondary school, when using a
pipette I wasn’t very accurate and would usually press to hard and let too much of the solution out,
which would alter the recommended value. Whilst carrying out the experiment, I became more stable in
using a pipette and learnt how important it was to be accurate. In doing this I also learnt how important
it was to be at eye level in order to read the results and see if they rested on the bottom of the meniscus
line. In the future, I would like to use and automated pipette as this would be quicker and more efficient.
When using the burettes, I would often forget if the funnel was still on top of it, or if the tap of it was
open when filling it with liquid. As I gained more practise I no longer needed to think about these things
as I remember to do these with practise. When transferring liquid from the pipette to the flask, initially I
, would lose some of the solution, however I found a technique and I am now able to transfer the whole
liquid into the flask without losing any of it so that accurate results can be produced.
How did I work to appropriate standards and protocols?
I learnt the purpose and function of the apparatus and this allowed me to achieve accurate results
safely. For example, when handling the hydrochloric acid I acknowledged that it was a corrosive
substance and reading the safety sheet, I knew that it could irritate the skin and eyes, so I had to follow
several risk assessments to evaluate the possible hazards. We were briefed on the control measures to
be taken in order to prevent the hazard. I took precautions by wearing PPE such as safety gloves and
goggles to protect myself.
How did I apply safe working practices and behaviour?
I ensured safe working practises and behaviour by reading the safety sheet before I carried out the
experiment. This made me aware of the possible risks and hazards and what precautions to take. I made
sure my working space with clean so that no accidents or spillages would occur. I made sure that I was
handling the substances safely and holding them properly, I moved around in a safe manner and made
sure not to run around the lab. I made sure all glassware such as beakers were far from the edge of the
table so they wouldn’t fall and smash.
I realised the importance of keeping my work space tidy with all the chemicals and glassware and
equipment in one place together. I labelled my glass beakers with the name of the solutions inside them
so I wouldn’t forget which one I was dealing with and this was important to also ensure I didn’t
contaminate anything. After the experiment I made sure that all the equipment was immediately put
away so that it wasn't broken or misplaced. If something like this did happen it could hinder everyone's
progress and could produce inaccurate results for other students.
Taking responsibility and communication
I worked together with a partner to complete this experiment. I take responsibility for my work as well
as my partner. Before starting the experiment we were given a sheet with a step by step method
explaining on how to undertake the practical. This helped us understand what to expect and the desired
outcome of the experiment.
My partner and I both had to know our roles and we worked together as a team in order for the
titration experiment to be effective and accurate. For example, when titrating the hydrochloric acid, one
person would open the burette tap and take the readings, and the other would stir the mixture
underneath with a metal stirrer and would say when it changed colour. As we were doing the practical
my partner and I both gave feedback to each other. This would include my partner telling me to
remember to keep eye level so that I could take an accurate reading of the reading being in line with the
meniscus line and me telling my partner to remember to clean the rod between each stir.
For the experiment, there wasn’t enough equipment for everyone, so we all had to share and wait turns
to use the equipment. My partner and I did this by one person keeping communication with the people
located at the balance, while the other set up the remaining apparatus for the practical. This was
essential for us in order not to waste any time whilst carrying out the practical and also to ensure good
communication with others working around us so we weren’t confused or waiting too long.
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