Unit 2D- Reviewing my development for the practicals: Titration, Colorimetry, Calorimetry
and Chromatography
Introduction:
This past year, I have learned many practical techniques and skills. Prior to this course, I
hadn’t used a colorimeter or carried out titration. Most of my class had not done these
practicals before, so it was a new skill for most of us to learn.
I had carried out chromatography experiments when I was in secondary school. As a result, I
was able to apply this skill to the 2C experiment.
At the beginning of the year, I struggled measuring volumes accurately, as I often allowed
the burette taps to run longer than required. After some practice, I improved this skill, so my
results became more accurate as I developed this skill.
Titration practical:
Key skill gained from the titration practical:
For Unit 2A, there were many skills I needed to develop when carrying out a titration, as I
had never carried out one before. I had never been taught a calibration before, as a result, it
was a new skill I had to learn. Calibrations will be useful in the future, as I can gather
accurate results when carrying out scientific practicals in a laboratory. In addition, some of
my class had never done a titration before so I was confident on building my skills and
developing my knowledge of titrations.
Another skill I learned was weighing items to a full gram. To carry out this skill, I had to be
very patient and resilient. I had to weigh sodium carbonate using a mass balance, as it was
in powder form it was very challenging to measure it to the exact amount needed. To
improve my precision, I added small amounts of sodium carbonate powder using a spatula
to get the mass I required. This skill guarantees my accuracy in my results and I can transfer
this skill in the future.
Lastly, I improved on identifying the hazards and risks for each of the experiments. When
using hazardous material, I had to explain and list the control measures to prevent the
hazards from occurring. Before the course, I understood the terms control measures,
hazards and risks, and these all linked to safety precautions. In addition, I understood the
difference between corrosive and irritants. I had to learn the specific hazards for the different
molars of acids and alkalines to prevent any accidents. I developed the skill for future
experiments, I can now safely use all of the equipment and dangerous solutions safely.
How I worked to appropriate standards and protocols in the titration experiment:
With every experiment, I learned the purpose of all the apparatus to fulfil the standards and
procedures that are used in a laboratory. By understanding the pieces of apparatus and their
functions, I was able to achieve my results accurately whilst maintaining a safe environment.
I had to know the hazards of all the equipment and what it's used for, especially when
,handling dangerous substances. To evaluate hazards, I had to follow risk assessments and
ensure all the equipment I used was appropriate for my experiment
How did I apply safe working practices and behaviours into my titrations:
In my titration, I applied a safe working environment to keep my class and I safe. On
occasion, I had spilled some substances such as hydrochloric acid. This is an irritant and
corrosive substance which can cause burns to the skin and blindness. Without cleaning up
the acid spill, one of my peers may have been harmed. As a result, I immediately cleaned
up the solution to prevent any possible hazards. This suggests that I can follow health and
safety legislations and precautions.
For my titration, did I take responsibility for my work and mistakes?
I believe I took full responsibility for my titration. I was able to engage myself in learning and
carrying out all of the practical methods. This further developed my titration knowledge, as I
was now more familiar with the structure of a titration practical. A few times, I did run the
burette tap for longer than required, for this I highlighted the point where I made the error,
and determined I could have a high percentage error from my experiment.
In my titration practical, did I take responsibility for completing the tasks and procedures in
the experiment?
Due to the fully detailed methods we were given to carry out the practical, we had a better
understanding of the results we were meant to obtain. In the titration practical, my class and
I worked in pairs or in groups of three. In addition, the responsibility of knowing the future
steps in the practical was all of our responsibility to carry out the practical. For our
experiment, my group and I assigned roles and set a time frame to do the practical in. By
acting as a team, we proved this to be beneficial to such a specific and precise practical.
Therefore, we were able to collect more reliable results and limit errors.
Did I communicate and cooperate well with my group members when carrying out my
titration?
For my experiment, I worked as a group of three. I believe that my group and I
communicated very well and all equally cooperated in the practical. When myself or my
peers were struggling with a task, we all assisted one another. Furthermore, we all gave
each other positive and constructive feedback to improve in the future.
The feedback I received from my partner:
To improve my future performance, my peers gave me constructive feedback for my
cooperation and work during the practicals. One thing my pers highlighted to me was to
clean the stirring rod every time I changed solution, pour only 3 small drops of methyl orange
in the sodium hydroxide and to close the tap fully when dispensing hydrochloric acid. By
giving me this feedback, I could acknowledge this for the future titrations we carried out to
gather more reliable results. Overall, my peers said my performance was good but my
accuracy could be improved.
, The feedback I gave to my partner? Did I find giving constructive feedback difficult?
Personally, I found giving constructive feedback rather easy. By speaking constructively, the
improvements I gave to my peers were beneficial, and carried out accurately in the other
titrations. However, when the practicals were carried out to high precision and accuracy, it
was difficult to suggest improvements. For each practical, I observed my pers performance
to suggest constructive feedback. One improvement I suggested was to ensure the
meniscus line was in line with the desired volume of the solution. This helped the overall
accuracy and reliability of the results as we had the precise amount of solution needed for
the experiment. Giving and receiving feedback was overall very successful. My partners and
I were able to identify our mistakes that we perhaps could have missed.
How did I recognise errors / problems in my experiment?
There were many instances which possibly may have affected my results. As a result, it was
crucial to identify these issues and create solutions for these errors. One error I identified
was I left air bubbles in my volumetric pipette. The volume of the solution is not accurate,
due to the presence of air. To accurately measure the volume, we slowed down the time we
spent to take up the solution so no air bubbles were created.
Furthermore, I was recognising the solution colour from yellow / orange to a pink colour. The
first few times we carried out this practical, we added too much of the dye, so the colour
change wasn’t accurate. The colour we originally there was an off pinky / orange colour, so
there wasn't a noticeable change. When we repeated the experiment, we used 3 small drops
of Methyl Orange indicator so we could see the colour change from orange to pink.
I identified any errors by analysing the anomalous result from my titration practicals. On
occasion, my peers were unable to use a volumetric pipette, I recognised that this may have
affected some of our experiments results. It can affect the reliability and accuracy of our
results and so I made my peers aware of this, and helped them improve on their technique.
How did I organise and use resources to complete my titration experiments?
I believe I used the equipment correctly. When I measured the volume of solutions, I made
sure the meniscus line touched the desired volume of the solution. Whilst I was able to do
this accurately, I struggled to use the burette tap.
How did I maintain and enhance my knowledge?
To maintain good results from all of my titration practicals, I repeated my experiments ⅔
times. To maintain accurate and precise results, I was able to select the most accurate trails
out of the three attempts, or calculate the average results. In addition, I calibrated my
equipment to achieve precise and accurate results for the end results in my experiment.
What do I need to improve on for my titration experiment?
