Criteria covered by this task:
Unit/Criteria
To achieve the criteria you must show that you are able to:
reference
Evaluate scientific skills developed in terms of potential for future
D.D4 - Y
progression.
D.M4 - Y Analyse skills developed and suggest improvements to own practice.
Summarise key personal competencies developed in relation to scientific
D.P7 - Y
skills undertaken.
I Certify this is my own work:
How am I doing?
Working to appropriate standards and protocols:
In Unit 2 of Applied Science, following appropriate standards and protocols is essential for
accurate and reliable experimental results. Let us explore specific examples where skill is
utilized in titration, cooling curves with stearic acid and paraffin wax, and thin paper
chromatography, along with my confidence level in these skills before starting Unit 2.
A. Titration: Performing an acid-base titration to determine the concentration of hydrochloric
acid (HCl) using sodium hydroxide (NaOH) as the titrant.
Skill Utilized: Accurate measurement and precise addition of titrant and indicator.
In this experiment, I had to carefully measure the volume of hydrochloric acid and add the
hydrochloric acid solution drop by drop until the endpoint was reached. This required good
control over the rate of titrant addition, ensuring that each drop was accurately added and
mixed. Additionally, the use of an appropriate indicator (such as phenolphthalein or methyl
orange) and the ability to detect subtle colour changes were crucial for determining the
endpoint accurately. I had some prior experience with titrations and had a moderate level of
confidence in my skills. However, I recognized the importance of careful measurement and
precise technique to ensure accurate results.
B. Cooling Curves with Stearic Acid and Paraffin Wax: Constructing cooling curves for stearic
acid and paraffin wax to determine their melting points.
Skill Utilized: Recording temperature at regular intervals, plotting data accurately, and
identifying phase changes.
In this experiment, I needed to monitor the temperature changes of stearic acid and paraffin
wax as they were heated and subsequently cooled. Accurate recording of temperature at
regular intervals allowed for the construction of cooling curves. Skill in plotting the data
accurately and identifying the points corresponding to phase changes (such as melting and
solidification) were critical for determining the melting points of the substances.
Confidence Level Before Unit 2: I had limited experience with cooling curves and was not
particularly confident in my skills. However, I understood the importance of precise
temperature measurements and data recording for constructing accurate cooling curves.
C. Thin Paper Chromatography:
Separating plant pigments using thin paper chromatography. Skill Utilized: Proper application
of the sample, solvent selection, and interpretation of chromatograms. In this experiment, I
needed to apply the sample (e.g. spinach extract) onto the chromatography paper accurately,
ensuring that the spot was concentrated but not overloaded. Skill in selecting an appropriate
solvent system, such as a suitable mobile phase, was necessary for achieving good separation
of the pigments. Additionally, interpreting the resulting chromatograms and identifying the
, different pigment bands required a keen eye for detail and an understanding of the principles
of chromatography.
Confidence Level Before Unit 2: I had some prior experience with thin paper chromatography
as I had only conducted the experiment each once but felt that my skills could be further
improved. I understood the importance of precise sample application and careful solvent
selection for obtaining clear and distinct separation of pigments. D.P7
In conclusion, before starting Unit 2, I had varying levels of confidence in the skills used in
titration, cooling curves, and thin paper chromatography. While I had some prior experience in
these techniques, I recognized the need to adhere to appropriate standards and protocols to
ensure accurate and reliable results. Through the unit, I aimed to further develop and refine
these skills to achieve greater proficiency and confidence in carrying out these experiments.
Improvements to consider:
To enhance my ability to work to appropriate standards and protocols in science, I can focus
on improving specific skills in each experiment. In titration, I can further refine my technique
by ensuring precise measurement and controlled addition of titrant and indicator. For cooling
curves, I can pay even closer attention to recording temperature at regular intervals and
accurately plotting data to identify phase changes. In thin paper chromatography, I can
concentrate on applying the sample accurately, selecting optimal solvents, and honing my
interpretation skills for clearer chromatograms. By actively seeking opportunities to practice
and improve these skills, I can work more effectively and consistently produce accurate and
reliable experimental results, maintaining high standards and adherence to protocols. D.M4
Applying safe work practices and behaviour & behaviour for safe and effective working in
science:
Unit 2A - Titration: Before starting Unit 2, I had some prior experience with titration
techniques and felt reasonably confident in my skills. However, during one titration
experiment, I encountered a scenario where applying safe work practices and behaviour
became crucial. In this experiment, I was tasked with determining the concentration of an
unknown acid solution using a standardized sodium hydroxide (NaOH) solution. The acid
solution was known to be corrosive and potentially harmful if mishandled.
To ensure safety, I carefully read the material safety data sheet (MSDS) for both the acid and
NaOH solutions, familiarizing myself with the hazards and appropriate handling procedures. I
ensured that I was wearing appropriate personal protective equipment (PPE), including safety
goggles and gloves, before starting the experiment. Additionally, I set up my workspace in a
well-ventilated area and made sure all necessary equipment, such as the burette, pipettes,
and beakers, were clean and in good working condition. D.P7
During the titration, I maintained a steady pace and used proper techniques to add the NaOH
solution to the acid solution. I was mindful of not splashing or spilling any solutions, as even
small amounts of the corrosive substances could cause harm. I also had a sink nearby in case
of accidental contact with the solutions, allowing me to rinse immediately if needed.
Throughout the experiment, I paid close attention to the colour change during the titration
process, ensuring that I stopped the addition of NaOH solution as soon as the endpoint was
reached. This careful observation helped prevent excessive use of the NaOH solution, which
could potentially introduce errors or waste chemicals.
By applying safe work practices and behaviour in this titration experiment, such as wearing
appropriate PPE, working in a well-ventilated area, and using proper techniques to handle
2
BTEC Assignment Brief v1.0
BTEC Internal Assessment QDAM January 2015
