Zoe Bella Hollingsworth
Pearson level 3 national diploma in forensic and criminal investigation
Unit 2d assignment 4
P7: Summarize key personal competencies developed in relation to scientific skills
undertaken.
Unit 2a assignment 1 (part 1)
Prior to starting this assignment, I only had a limited knowledge of certain scientific
skills. I did know how to make up basic solutions using water. I also knew how to
write up risk assessments and take the right precautions to make sure that no one
gets hurt during the practical, like for example in this assignment I made sure to
wear goggles because we were using methyl orange which can irritate the skin or
eyes.
In this assignment we did titration using an indicator and pH meter, in this half of
the experiment we used an indicator. To start with we made up our solution using
sodium carbonate and distilled water, we also calibrated our scales and burette
using distilled water. We moved the Na 2CO3 into a volumetric flask, then we
calibrated our pipette using distilled water. We put 25cm 3 of our solution into a
conical flask, which we then put a few drops of methyl orange indicator into, then
we titrated our solution until it turned from orange to pink, recording our results in a
table.
Key skills learnt (using an indicator):
Learned how to calibrate scales with weights and a burette and a pipette
using distilled water.
Using a measuring scale to measure out the sodium carbonate.
Using an indicator to pinpoint when neuralization happened.
Used a burette to titrate our solution to neutralize an acid.
Creating our own solution using sodium carbonate and distilled water.
In this half of the experiment, we used a pH meter. To start with we calibrated our
pipette using distilled water, we also calibrated the pH meter using two solutions,
one was pH4 and the other was pH7, we placed the pH meter into each beaker and
using a screwdriver we changed the reading on the pH meter to the pH of the
solution, then we transferred 25cm 3 of our sodium carbonate solution into a small
beaker. We then added hydrochloric acid to the burette we were using and put the
beaker with the sodium carbonate in it, under the burette, then we added 1cm of
hydrochloric acid until we had added most of it into the solution. We then wrote
down each pH reading after every cm 3 added, into a table.
Key skills learned (using a pH meter):
Learned how to calibrate a pH meter using buffering solutions.
Neutralized an acid and a base.
Used a burette to titrate a solution.
, Calibrated a burette using hydrochloric acid.
Used a pH meter to indicate when our solution had neutralized.
Unit 2a assignment 1 (part 2)
Prior to this assignment I had a limited knowledge of any scientific skills. I knew how
to write up risk assessments and what precautions to take so that me and the
person that I worked with didn’t get injured, for example wearing gloves, a lab coat
and goggles. I had a brief knowledge of how to use a colorimeter and use those
results to plot a graph, then to determine the absorption of a solution.
In this part of the experiment, we did colorimetry, where to start with we calibrated
the colorimeter using distilled water, and then using the undiluted solution, we
made it into a diluted solution of 0.8mol, 0.6mol, 0.4mol and 0.2mol. We used the
colorimeter to determine the absorption of each solution and the absorption of
solution X. We put all the results into a table and then plotted out a graph and found
out how many moles were in solution X.
Key skills learnt:
Learned how to calibrate a colorimeter with distilled water.
Diluted a solution and made it into another solution.
Plotted a graph to find out how many moles were in a solution.
Used colorimeter to determine the absorption of a solution.
Plotted a graph using results from the experiment.
Unit 2b assignment 2
Prior to this assignment, I didn’t have many scientific skills, but I did know how to
calibrate thermometers because of the past assignments we did, I also knew how to
use the thermometer to measure the temperature of different solutions. I also had
prior knowledge of how to write up risk assessments and of what precautions to
take to make sure that the experiment runs smoothly.
In this experiment, we examined cooling curves, to start with we calibrated the two
thermometers, using two beakers with one full of boiling water in it (after being
heated by a Bunsen burner) and the other one full of ice water. For the first half of
this experiment, we heated up the stearic acid until it had melted, using boiling
water. Then we took it out of the boiling water, placed a thermometer into the test
tube and wrote down a reading after a minute, for 44 minutes, we placed these
results into a table of results and plotted a graph. In the second half of this
experiment, we heated the paraffin wax until it had melted using boiling water, took
the test tube out and did the same this as we did with the stearic acid.
Key skills learnt:
Learned how to calibrate a digital and a liquid thermometer.
Successfully used a Bunsen burner to boil water.
Plotted two graphs to determine three gradients on each of them.
Used a thermometer to take readings of stearic acid and paraffin wax.
The results taken produced a cooling curve on the graph plotted.
