scientific report
Proving the Beer Lambert Law
Abstract:
For this experiment we tested the absorbency of copper sulphate in different concentrations to prove the Beer Lambert Law.
Introduction:
This Law: Provides an experimental link between the absorbance properties of a solution of a given compound and its concentration. This is normally expressed as .
A = Absorbance measured
= Absorptivity
C = Molar concentration
L = Length of cuvette
Equipment:
• Gilson pipette
• Eppendorf tubes
• Copper sulphate
• Spectrophotometer
• Cuvettes
• Distilled water
Method:
1. Use a Gilson pipette to measure out five different solutions of copper sulphate and distilled water.
2. Pour into a 1.5ml test tube, label each tube 1 to 5 to indicate each solution and place the tubes into a test tube rack.
Concentration of: Copper sulphate Water
Test tube 1 100% 0%
Test tube 2 80% 20%
Test tube 3 60% 40%
Test tube 4 40% 60%
Test tube 5 20% 80%
3. Using an spectrophotometer, record the absorbency concentration of each solution. Repeat this for each test tube to obtain an average.
4. Use a gilson pipette to transfer the solution from the test tube to a clean cuvette. This is standardising the solution.
5. Place the cuvette firmly into the machine and then press the green button to take a reading. This should be done 5 times.
6. Repeat steps 3-6 while thoroughly cleaning the cuvette between each solution to avoid odd results.
Results:
Concentrations Test 1 Test 2 Test 3 Test 4 Test 5 Average
100% copper sulphate 0.563 0.546 0.544 0.551 0.547 0.5402
80% copper sulphate 0.471 0.470 0.473 0.470 0.470 0.4708
60% copper sulphate 0.346 0.345 0.339 0.339 0.345 0.3428
40% copper sulphate 0.249 0.246 0.249 0.245 0.247 0.2472
20% copper sulphate 0.105 0.106 0.108 0.102 0.100 0.1006
See accompanying graph. Conclusions:
1. From the graph we can clearly see that as the copper sulphate solution increases, the absorbance concentration increases.
2. From these results, it’s clear to
Abstract:
For this experiment we tested the absorbency of copper sulphate in different concentrations to prove the Beer Lambert Law.
Introduction:
This Law: Provides an experimental link between the absorbance properties of a solution of a given compound and its concentration. This is normally expressed as .
A = Absorbance measured
= Absorptivity
C = Molar concentration
L = Length of cuvette
Equipment:
• Gilson pipette
• Eppendorf tubes
• Copper sulphate
• Spectrophotometer
• Cuvettes
• Distilled water
Method:
1. Use a Gilson pipette to measure out five different solutions of copper sulphate and distilled water.
2. Pour into a 1.5ml test tube, label each tube 1 to 5 to indicate each solution and place the tubes into a test tube rack.
Concentration of: Copper sulphate Water
Test tube 1 100% 0%
Test tube 2 80% 20%
Test tube 3 60% 40%
Test tube 4 40% 60%
Test tube 5 20% 80%
3. Using an spectrophotometer, record the absorbency concentration of each solution. Repeat this for each test tube to obtain an average.
4. Use a gilson pipette to transfer the solution from the test tube to a clean cuvette. This is standardising the solution.
5. Place the cuvette firmly into the machine and then press the green button to take a reading. This should be done 5 times.
6. Repeat steps 3-6 while thoroughly cleaning the cuvette between each solution to avoid odd results.
Results:
Concentrations Test 1 Test 2 Test 3 Test 4 Test 5 Average
100% copper sulphate 0.563 0.546 0.544 0.551 0.547 0.5402
80% copper sulphate 0.471 0.470 0.473 0.470 0.470 0.4708
60% copper sulphate 0.346 0.345 0.339 0.339 0.345 0.3428
40% copper sulphate 0.249 0.246 0.249 0.245 0.247 0.2472
20% copper sulphate 0.105 0.106 0.108 0.102 0.100 0.1006
See accompanying graph. Conclusions:
1. From the graph we can clearly see that as the copper sulphate solution increases, the absorbance concentration increases.
2. From these results, it’s clear to
References: Hornby D. 2014 Project based learning, Life Sciences UTC.