Title: Preparation of a Standard Solution of Potassium Chloride
Objective: The objective of this experiment is to prepare a standard solution of potassium chloride (KCl) with a known concentration using a 3.73g sample of KCl and a 250 ml volumetric flask.
Materials:
- Potassium chloride (KCl) sample (3.73g)
- Distilled water
- Analytical balance
- 250 ml volumetric flask
- Weighing boat or paper
- Spatula
- Stirring rod
Procedure:
Weighing of Potassium Chloride: a. Set up an analytical balance and ensure it is calibrated. b. Place a clean weighing boat or paper on the balance. c. Carefully add and record the mass of the potassium chloride sample. The mass should be 3.73g with appropriate precision.
Transfer of Potassium Chloride to Volumetric Flask: a. Prepare a clean 250 ml volumetric flask. b. Using a spatula, transfer the weighed potassium chloride sample into the volumetric flask. c. Be cautious not to spill or lose any of the sample during transfer.
Dissolving Potassium Chloride: a. Add a small volume of distilled water to the volumetric flask containing the KCl. b. Using a stirring rod, gently stir the mixture to dissolve the KCl in the water. c. Ensure all KCl particles are dissolved completely.
Filling the Volumetric Flask: a. Gradually add more distilled water to the volumetric flask until the solution reaches the calibration mark (250 ml) on the neck of the flask. b. Be careful not to overfill the flask. Once the solution reaches the mark, it should be at the desired volume of 250 ml.
Mixing and Homogenizing: a. Place the stopper or cap securely on the volumetric flask. b. Invert the flask several times to mix the solution thoroughly and ensure homogeneity.
Labeling and Storage: a. Properly label the volumetric flask with the necessary information, including the concentration, date, and any other relevant details. b. Store the standard solution in a safe location, protected from light or other factors that may cause degradation or contamination.
Calculations: To determine the concentration of the potassium chloride standard solution, divide the mass of KCl used (3.73g) by the volume of the solution (250 ml).
Concentration (C) = Mass of KCl (m) / Volume of Solution (V)
Example calculation: C = 3.73g / 0.250L = 14.92 g/L or 14.92 mg/ml
Conclusion: In this experiment, a standard solution of potassium chloride with a concentration of 14.92 mg/ml (or 14.92 g/L) was successfully prepared using a 3.73g sample of KCl and a 250 ml volumetric flask. The solution can now be used for various analytical purposes, such as calibration, dilution, or comparison against other unknown samples.