Understanding the Terms
* Molarity (M): Represents the concentration of a solution. A 2 M solution means there are 2 moles of KCl dissolved in 1 liter of solution.
* Moles: A unit of measurement for the amount of substance.
* KCl: The chemical formula for potassium chloride.
Materials
* Potassium chloride (KCl) solid
* Distilled water
* Graduated cylinder (250 ml)
* Weighing scale
* Beaker
* Stirring rod
Procedure
1. Calculate the Mass of KCl:
* Molar mass of KCl: 74.55 g/mol (39.10 g/mol for K + 35.45 g/mol for Cl)
* Moles of KCl needed: (2 M) * (0.250 L) = 0.5 moles
* Mass of KCl needed: (0.5 moles) * (74.55 g/mol) = 37.275 g
2. Weigh the KCl:
* Use a weighing scale to accurately weigh out 37.275 grams of KCl.
3. Dissolve in Water:
* Add approximately 150 ml of distilled water to a beaker.
* Carefully add the weighed KCl to the water and stir until it completely dissolves.
* Once dissolved, carefully transfer the solution to a 250 ml graduated cylinder.
* Add more distilled water to the graduated cylinder until the total volume reaches 250 ml.
4. Mix Thoroughly:
* Stir the solution with a stirring rod to ensure the KCl is fully dissolved and the concentration is uniform.
Important Notes:
* Safety: Always wear appropriate safety goggles and gloves when handling chemicals.
* Distilled Water: Use distilled or deionized water to minimize impurities that can affect the solution's accuracy.
* Dissolving: The dissolving process can generate heat. Allow the solution to cool to room temperature before making any final volume adjustments.
Labeling:
* Label the solution with the following information:
* Potassium Chloride (KCl)
* Concentration (2 M)
* Date prepared
Let me know if you have any other questions!
