How am I doing?
During Unit 2: Practical Scientific Procedures and Techniques, I conducted a range of experiments,
including titration, colorimetry, chromatography, and calorimetry. These experiences significantly
enhanced my laboratory skills and deepened my understanding of scientific procedures. This unit has
made me more independent and self-assured in conducting practical work, which will be beneficial
when applying to universities and apprenticeships. Reflecting on my performance, I've realised the
value of the skills I have gained and their applicability to other areas of my course.
In Assignment 2A, I performed a titration of sodium carbonate (Na₂CO₃) against hydrochloric acid
(HCl) to determine the concentration of sodium hydroxide (NaOH) in an unknown solution. This
involved making a standard solution of Na₂CO₃ to titrate against HCl, allowing me to find its
concentration, The gradual colour change during the titration experiment made it a little difficult to
discern the titration's endpoint. This might be explained by the type of indication that was employed.
For instance, the tiny change from colourless to pink when employing phenolphthalein necessitated
close attention. A modest divergence in the titration volumes from the theoretical values was an
unexpected result. This deviation could be attributed to fluctuations in the hydrochloric acid content or
to small impurities in the sodium carbonate. Several titrations were carried out to increase accuracy,
and an average value was obtained to reduce mistakes. This demonstrated how crucial duplicates are
to getting accurate data. Additionally, I carried out a colorimetry experiment, preparing a 1M copper
sulphate solution and performing serial dilutions with distilled water to create different concentrations.
Each concentration's transmittance was measured using a colorimeter. During the colorimetry
experiment, an unexpected higher transmittance value for one of the lower concentration solutions
was one anomaly that was seen. This might be the result of a little amount of contamination or a
mistake made when making the serial dilutions. In order to rectify this, the experiment was conducted
again, making sure that every piece of glassware was well cleaned and that exact measurements
were made. The colorimeter's calibration could be another possible source of inaccuracy. To
guarantee that the readings were accurate, routine calibration tests were carried out. Notwithstanding
these difficulties, the general pattern of the data showed a strong agreement with Beer-Lambert's
equation, proving the accuracy of the colorimetric method of concentration measurement.Throughout
these experiments, I ensured that the equipment was calibrated correctly, substances were measured
accurately, and equipment was handled with care. This assignment involved both familiar skills and
the development of new ones.
For Assignment 2B, I conducted a calorimetry experiment to observe the cooling curves of stearic
acid and paraffin wax. This required calibrating equipment, creating graphs to represent the cooling
curves, and conducting risk assessments to ensure safety.The cooling curve of stearic acid in the
calorimetry experiment showed an unexpected plateau, indicating that the phase shift happened at a
different temperature than first thought. This might be the result of contaminants in the stearic acid
sample or temperature changes in the surrounding area throughout the experiment. Furthermore,
small variations in the cooling curves were observed, which might be attributed to variations in the
stirring rate or heat loss to the environment. These aberrations highlighted how crucial it is to keep a
consistent approach and a regulated environment. The significance of experimental control in
calorimetry was emphasised by the more consistent findings that were achieved by repeating the
experiment and using an insulated container. Constructing these graphs and carrying out the
experiment involved both skills I was already familiar with and those I developed during the process.
Assignment 2C involved performing three different chromatography techniques. I conducted paper
chromatography to separate amino acids, thin-layer chromatography (TLC) to separate plant extracts,
and another paper chromatography to separate plant extracts. These experiments required extreme
care and attention to detail to ensure accurate results.One anomaly found in the chromatography
During Unit 2: Practical Scientific Procedures and Techniques, I conducted a range of experiments,
including titration, colorimetry, chromatography, and calorimetry. These experiences significantly
enhanced my laboratory skills and deepened my understanding of scientific procedures. This unit has
made me more independent and self-assured in conducting practical work, which will be beneficial
when applying to universities and apprenticeships. Reflecting on my performance, I've realised the
value of the skills I have gained and their applicability to other areas of my course.
In Assignment 2A, I performed a titration of sodium carbonate (Na₂CO₃) against hydrochloric acid
(HCl) to determine the concentration of sodium hydroxide (NaOH) in an unknown solution. This
involved making a standard solution of Na₂CO₃ to titrate against HCl, allowing me to find its
concentration, The gradual colour change during the titration experiment made it a little difficult to
discern the titration's endpoint. This might be explained by the type of indication that was employed.
For instance, the tiny change from colourless to pink when employing phenolphthalein necessitated
close attention. A modest divergence in the titration volumes from the theoretical values was an
unexpected result. This deviation could be attributed to fluctuations in the hydrochloric acid content or
to small impurities in the sodium carbonate. Several titrations were carried out to increase accuracy,
and an average value was obtained to reduce mistakes. This demonstrated how crucial duplicates are
to getting accurate data. Additionally, I carried out a colorimetry experiment, preparing a 1M copper
sulphate solution and performing serial dilutions with distilled water to create different concentrations.
Each concentration's transmittance was measured using a colorimeter. During the colorimetry
experiment, an unexpected higher transmittance value for one of the lower concentration solutions
was one anomaly that was seen. This might be the result of a little amount of contamination or a
mistake made when making the serial dilutions. In order to rectify this, the experiment was conducted
again, making sure that every piece of glassware was well cleaned and that exact measurements
were made. The colorimeter's calibration could be another possible source of inaccuracy. To
guarantee that the readings were accurate, routine calibration tests were carried out. Notwithstanding
these difficulties, the general pattern of the data showed a strong agreement with Beer-Lambert's
equation, proving the accuracy of the colorimetric method of concentration measurement.Throughout
these experiments, I ensured that the equipment was calibrated correctly, substances were measured
accurately, and equipment was handled with care. This assignment involved both familiar skills and
the development of new ones.
For Assignment 2B, I conducted a calorimetry experiment to observe the cooling curves of stearic
acid and paraffin wax. This required calibrating equipment, creating graphs to represent the cooling
curves, and conducting risk assessments to ensure safety.The cooling curve of stearic acid in the
calorimetry experiment showed an unexpected plateau, indicating that the phase shift happened at a
different temperature than first thought. This might be the result of contaminants in the stearic acid
sample or temperature changes in the surrounding area throughout the experiment. Furthermore,
small variations in the cooling curves were observed, which might be attributed to variations in the
stirring rate or heat loss to the environment. These aberrations highlighted how crucial it is to keep a
consistent approach and a regulated environment. The significance of experimental control in
calorimetry was emphasised by the more consistent findings that were achieved by repeating the
experiment and using an insulated container. Constructing these graphs and carrying out the
experiment involved both skills I was already familiar with and those I developed during the process.
Assignment 2C involved performing three different chromatography techniques. I conducted paper
chromatography to separate amino acids, thin-layer chromatography (TLC) to separate plant extracts,
and another paper chromatography to separate plant extracts. These experiments required extreme
care and attention to detail to ensure accurate results.One anomaly found in the chromatography
