Chemistry


Purpose: - To prepare a standard solution of know concentration of copper(II)nitrate trihydrate. To prepare various dilutions of the standard solution. To measure the % transmittance or absorbance of the solutions using the spectrophotometer and to construct a calibration graph from the data. To obtain the concentration of an unknown solution using the calibration graph.


Materials: - 100ml beaker, spectrophotometer, safety goggles, test-tube rack, 5 test tube.


Method: - 1. Obtained 5 test tubes (18mm x 150mm) and labeled them from A to E.


2. In test tube A, placed about 10ml of your stock 0.500ml Copper(II) Nitrate Trihydrate solution.


3. A diluted solution was prepared by placing 8.0ml of the stock in a 25ml graduated cylinder and added distilled water until the solution was up to the 20.0ml mark


4. Step 3 was repeated using 10.0ml of solution B and 100 ml of distilled of water. This diluted was transferred to test tube C.


5. Step 3 was repeated using 10.0ml of solution C and 100 ml of distilled of water. This diluted was transferred to test tube D.


6. Step 3 was repeated using 10.0ml of solution D and 100 ml of distilled of water. This diluted was transferred to test tube E.


7. The concentration of the diluted solution B to E was calculated.


8. Solution A to E was transferred into five curvettes or five 13mm x 100 mm test tubes.


9.


Observation: -


Test Tube


Concentration


%transmittance


A


5.500 ml


47.7


B


0.200 ml


79.6


C


0.100 ml


91.6


D


0.050 ml


95.6


E


0.025 ml


96.2