This document achieved a distinction grade, there was no feedback given apart from good work achieved. This document explains the steps taken in the first practical for unit 19 we did and is in the layout of a tutorial booklet as wanted.
In this assignment, a set of matrices will be outlined such as the determination of copper percentage
content in brass, the determination of bicarbonate concentration in bottled water and the
determination of iron (II) percentage content in a commercial tablet. Each experiment will have a set
of calculations and what was carried out in order to reach that calculation end point.
What is included in this tutorial booklet:
Experiment 1 -
Determination of copper percentage content in brass
A tutorial of how to conduct this experiment
Results collected
Calculations
Discussion of comparisons and errors
Safety measures
Experiment 2 -
Determination of iron (II) percentage content in a commercial iron tablet
A tutorial of how to conduct this experiment
Results collected
Calculations
Discussion of comparisons and errors
Safety measures
Experiment 3 –
Determination of bicarbonate concentration in bottled water
A tutorial of how to conduct this experiment
A set of results
A set of calculations
Discussion of comparisons and errors
Safety measures
, AmberSkye See
Experiment 1
The determination of copper percentage content in brass
In order to determine a percentage of copper content in brass, colorimetry was used throughout the
whole of the experiment.
How to conduct this experiment:
To start this experiment, weigh out 0.3g of brass into a small 25cm 3 glass beaker with a
spatula onto a calibrated weighing scale. The amount weighed in the conduction of my
experiment was 0.3016g rounded to 0.3g. Once this is done, take the beaker of brass over to
a fume hood and add 5cm of 5M nitric acid using a 3cm plastic pipette to the beaker. After
the nitric acid has been added, place it onto a hot plate, with a temperature around 60°C, to
dissolve the brass. After the brass has been fully dissolved, take the beaker off the hot plate
to cool down before transferring it into a small 10cm 3 glass volumetric flask with a funnel
and topping it up to the meniscus with distilled water. Stopper and invert the flask three
times.
In order to calculate a percentage of the copper content in brass, an already made solution
of Copper nitrate was used along with distilled water to find the concentration of the
unknown sample made to find the percentage. To make a set of diluted standard solutions
using the already made copper nitrate and distilled water, use the table as shown below to
prepare the solutions in different test tubes:
Concentration of 0.0 0.1 0.2 0.3 0.4 0.5
Cu(NO3) (aq)/mol
per dm3
Volume of 0 2 4 6 8 10
1mol/dm3 of
Cu(NO3)
Volume of distilled 10 8 6 4 2 0
water/cm3
Once the standard solutions have been prepared, calibrate a colorimeter using a cuvette of
distilled water measured ¾ full. Make sure the reading of the absorbency is set to Red (R).
After the first calibration has been done, transfer your standard solutions into different
cuvettes ¾ full and record results in a table. Repeat the readings of the solutions three times,
disposing of the waste Cu(NO3) each time and calibrating in between different recordings to
ensure full accuracy. Once the set of standard solutions has been done, repeat the process
with the brass solution made earlier. Round to 2dp each time for better accuracy.
When holding the cuvettes, I made sure to not hold them by the sides but rather the top and
bottom. This was to stop any residue on my gloves from smudging the sides of the cuvette
and affecting the light absorption, resulting in an inaccurate absorption reading.
AmberSkye See
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