Beer's Law Lab
Objective: The purpose of this lab is to demonstrate that there is a linear relationship between the number of molecules that can absorb light present in a solution and the amount of light absorbed by a solution. This lab should prove that Beer’s law and the equation A=a x b x c, is a linear relationship.
Procedure:
The only deviations in the lab procedure was that the stock solution was made before arrival to the lab with 0.570 g of KMnO4 in 0.500 L. The diluted solutions and the Spec 20 were used as directed in the lab manual. The same cuvette was used each time to eliminate error. Cuvettes are all made differently and have a difference in how they measure. If a new cuvette was used each time, the data would be slightly off due to the possibility of each cuvette having different characteristics which affect the measurements in the Spec 20.
Data Calculations:
To find the molarity of the stock solution:
*Note: Molarity is moles/ Liters so in the equation below the first half is finding the number of moles of KMnO4 and the second half is dividing the moles by the liters of the solution.
Grams of KMnO4 x (1 mole / molar mass (158.04g)) / Liters of stock solution = molarity of Stock Solution
0.570g KMnO4 x (1 mole / 158.04g) / 0.500 Liters = 0.00721 M
To find the molarity of solution #1:
*Note: To find the molarity of the first solution, use the molarity found for the stock solution. Since 5.00 mL of the stock solution was used to make solution 1, multiply the molarity of the stock solution by 5.00 mL to get the moles of solution 1. Once the moles of solution 1 have been found, divide that by the liters of water that were added to solution 1. The 0.10000 L comes from the 100 mL volumetric flask the solution was made in. mL of stock solution x (moles of stock solution / liter) / total liters of solution 1 (volumetric flask) = M of solution 1
5.00 mL stock solution x (0.00721 moles / 1000mL ) /
Procedure:
The only deviations in the lab procedure was that the stock solution was made before arrival to the lab with 0.570 g of KMnO4 in 0.500 L. The diluted solutions and the Spec 20 were used as directed in the lab manual. The same cuvette was used each time to eliminate error. Cuvettes are all made differently and have a difference in how they measure. If a new cuvette was used each time, the data would be slightly off due to the possibility of each cuvette having different characteristics which affect the measurements in the Spec 20.
Data Calculations:
To find the molarity of the stock solution:
*Note: Molarity is moles/ Liters so in the equation below the first half is finding the number of moles of KMnO4 and the second half is dividing the moles by the liters of the solution.
Grams of KMnO4 x (1 mole / molar mass (158.04g)) / Liters of stock solution = molarity of Stock Solution
0.570g KMnO4 x (1 mole / 158.04g) / 0.500 Liters = 0.00721 M
To find the molarity of solution #1:
*Note: To find the molarity of the first solution, use the molarity found for the stock solution. Since 5.00 mL of the stock solution was used to make solution 1, multiply the molarity of the stock solution by 5.00 mL to get the moles of solution 1. Once the moles of solution 1 have been found, divide that by the liters of water that were added to solution 1. The 0.10000 L comes from the 100 mL volumetric flask the solution was made in. mL of stock solution x (moles of stock solution / liter) / total liters of solution 1 (volumetric flask) = M of solution 1
5.00 mL stock solution x (0.00721 moles / 1000mL ) /