Pearson BTEC Level 3 National Foundation Diploma in
Qualification
Applied Science
Unit number and title Unit 2: Practical Scientific Procedures and Techniques
A: Undertake titration and colorimetry to determine the
Learning aim
concentration of solutions.
Colorimetry
Colorimetry is a technique used to see the concentration or intensity of the coloured
substances in solutions in the beer lambert law. This is done by using a colorimeter and some
other equipment, which is the following. The unknown colours can then be compared to known
colours. In addition, colourimetry is also an example of spectrophotometry.
Equipment
● Colorimeter
A colorimeter has 3 main parts, and is used to test the quality of water or screening chemicals
to see the quality of colours. This is done by a light that passes through the colour filter.
● Cuvette
A cuvette is a small and clear plastic and rectangular container, used for samples.
● Pipette
● Distilled water
● Volumetric Flask
● Burette
Summary of the method
To complete the colorimetry practical, the colorimeter has to be set to the correct wavelength.
The solutions then need to be made up, this is done by using 1 mole of copper sulfate, which is
a light blue colour by adding 10ml of it into a test tube, along with 10ml of distilled water,
which therefore makes 20ml of 0.5 mole of copper sulfate solution. This can be repeated to
make different solutions, and the measurements must be accurate so the calibration graph is
more accurate and follows an accurate pattern. In addition, the colorimeter is then used to
work out the absorbance, to use this, a reference (distilled water) is added to the cuvette and
into the colorimeter, which should be displayed with 0.00 Absorbance. If the display is
incorrect it needs to be redone.
Results
Concentration/mol
dm-3 Absorbance/A
1
BTEC Assignment Brief v1.0
BTEC Internal Assessment QDAM January 2015
, Attempt 1 2 3 Average Standard Dev
0.1 0.01 0.01 0.02 0.01 0.004
0.2 0.09 0.06 0.14 0.09 0.030
0.3 0.22 0.24 0.23 0.23 0.008
0.4 0.37 0.38 0.36 0.37 0.008
0.5 0.36 0.31 0.32 0.33 0.020
0.6 0.48 0.51 0.50 0.49 0.019
0.7 0.52 0.53 0.53 0.52 0.004
0.8 0.49 0.50 0.49 0.49 0.004
0.9 0.66 0.67 0.65 0.66 0.008
1.0 0.88 0.89 0.86 0.87 0.010
Unknown 0.37 0.4 0.39 0.39 0.008
I used my results to work out the unknown concentration of a substance
Evaluation
I believe that my results were comparable to the rest of the class, which meant that the
experiment overall went well. In addition, my unknown value was close to some of my peers'
2
BTEC Assignment Brief v1.0
BTEC Internal Assessment QDAM January 2015
Qualification
Applied Science
Unit number and title Unit 2: Practical Scientific Procedures and Techniques
A: Undertake titration and colorimetry to determine the
Learning aim
concentration of solutions.
Colorimetry
Colorimetry is a technique used to see the concentration or intensity of the coloured
substances in solutions in the beer lambert law. This is done by using a colorimeter and some
other equipment, which is the following. The unknown colours can then be compared to known
colours. In addition, colourimetry is also an example of spectrophotometry.
Equipment
● Colorimeter
A colorimeter has 3 main parts, and is used to test the quality of water or screening chemicals
to see the quality of colours. This is done by a light that passes through the colour filter.
● Cuvette
A cuvette is a small and clear plastic and rectangular container, used for samples.
● Pipette
● Distilled water
● Volumetric Flask
● Burette
Summary of the method
To complete the colorimetry practical, the colorimeter has to be set to the correct wavelength.
The solutions then need to be made up, this is done by using 1 mole of copper sulfate, which is
a light blue colour by adding 10ml of it into a test tube, along with 10ml of distilled water,
which therefore makes 20ml of 0.5 mole of copper sulfate solution. This can be repeated to
make different solutions, and the measurements must be accurate so the calibration graph is
more accurate and follows an accurate pattern. In addition, the colorimeter is then used to
work out the absorbance, to use this, a reference (distilled water) is added to the cuvette and
into the colorimeter, which should be displayed with 0.00 Absorbance. If the display is
incorrect it needs to be redone.
Results
Concentration/mol
dm-3 Absorbance/A
1
BTEC Assignment Brief v1.0
BTEC Internal Assessment QDAM January 2015
, Attempt 1 2 3 Average Standard Dev
0.1 0.01 0.01 0.02 0.01 0.004
0.2 0.09 0.06 0.14 0.09 0.030
0.3 0.22 0.24 0.23 0.23 0.008
0.4 0.37 0.38 0.36 0.37 0.008
0.5 0.36 0.31 0.32 0.33 0.020
0.6 0.48 0.51 0.50 0.49 0.019
0.7 0.52 0.53 0.53 0.52 0.004
0.8 0.49 0.50 0.49 0.49 0.004
0.9 0.66 0.67 0.65 0.66 0.008
1.0 0.88 0.89 0.86 0.87 0.010
Unknown 0.37 0.4 0.39 0.39 0.008
I used my results to work out the unknown concentration of a substance
Evaluation
I believe that my results were comparable to the rest of the class, which meant that the
experiment overall went well. In addition, my unknown value was close to some of my peers'
2
BTEC Assignment Brief v1.0
BTEC Internal Assessment QDAM January 2015
