Summary Unit 2 Learning Aim A Colorimetry Distinction Level

I Apinaya Amuthalingham I BTEC Applied Science I Coursework I Chemistry I
Colorimetry I Unit 2 I Learning Aim A I
Colorimetry :-
Equipment :-
- Colorimeter
- Cuvettes
- Pipette
- Glass Stirring Rod
- Measuring Cylinder - 10 cm3
- Test Tube Rack
- 6X Test Tubes - 10 cm3
- Beaker - 100 cm3
- Beaker - 250 cm3 1. Figure 1 - Colorimetry Diagram
( REF )
- Copper Sulfate ( CuSO4 ) - 0.40M

Method :-
1. Wear goggles for safety .
2. Obtain small volumes of 0.40M CuSO4 solution and distilled water in separate
beakers .
3. Label five clean , dry , test tubes one to five .
4. Use pipette to prepare five standard solutions according to the required amount
( shown in the results table ) .Thoroughly mix each solution with a stirring rod . Clean
and dry the stirring rod between uses .
5. Prepare a blank by filling an empty cuvette full with distilled water .
6. Place the blank in the cuvette slot of the colorimeter and close the lid .
7. Press the button on the colorimeter . When the LED stops flashing , the calibration is
complete .
8. Start collecting results and write them down in your results table .
9. Remove the cuvette from the colorimeter and pour out the water . Using the solution
in test tube 1 , rinse the cuvette twice with 1ml amounts , and then fill it full .
Wipe the outside of the civets with a tissue, place it in the colorimeter , and close the
lid .
10. When the absorbance readings have stabilised , write the absorbance value into your
results table .
11. Then discard the cuvette contents . Using the solution in test tube 2 , rinse the
cuvette with 1ml amounts , and then fill it full . Wipe the outside , place it in the
colorimeter , and close the lid . When the absorbance readings have stabilised , write
your results down .
12. Repeat this step again for test tube 3 , test tube 4 and the unknown concentration of
CuSO4 .
13. Obtain about 5ml of the unknown CuSO4 in another clean , dry , test tube . Record
the number of the unknown solution in your table .
14. Rinse the cuvette twice with the unknown solution and fill it about full . Wipe the
outside of the cuvette , place into the colorimeter , and close the lid .
15. Monitor the absorbance value . When this value has stabilised , record it in your data
table .



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, Results Table : Colorimetry :-
Trial Number 0.40M CuSO4 Distilled Water Concentration Absorbance
( ml ) H2O ( ml ) (M) ( AU )

1 2 8 0.08 0.82

2 4 6 0.16 1.72

3 6 4 0.24 2.15

4 8 2 0.32 2.50

5 10 0 0.40 2.63


Graph : Absorbance vs Concentration : Colorimetry :-




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