Write a brief procedure outling how would you prepare 250mL of a 0.150M solution of a CoCl2 from solid CoCl2 and distilled water
To prepare a 250mL of a 0.150M solution of CoCl2 from solid CoCl2 and distilled water, you would follow these steps:
1. Calculate the amount of CoCl2 needed:
- To do this, you would need to determine the molar mass of CoCl2, which is 129.84 g/mol.
- Multiply the molar mass by the desired molarity (in mol/L) and the desired volume (in L) to get the number of grams needed.
- For a 0.150M solution of 250mL (0.250L), the calculation would be: 0.150 mol/L * 0.250 L * 129.84 g/mol = 4.872 g
2. Weigh out the calculated amount of CoCl2:
- Using a balance, measure out 4.872 grams of solid CoCl2 using an accurate weighing scale.
3. Transfer the solid CoCl2 into a clean, dry 250mL beaker.
4. Add distilled water to the beaker:
- Place the beaker on a stirring plate or a magnetic stirrer.
- Slowly add distilled water to the beaker while stirring the mixture using a stirring rod.
- Continue to add water until the total volume reaches 250mL. You can verify the volume using a graduated cylinder or a volumetric flask.
5. Ensure the CoCl2 is completely dissolved:
- Stir the solution gently until the solid CoCl2 is completely dissolved. If any undissolved particles are present, continue stirring until they are dissolved.
6. Transfer the solution to a clean, labeled container:
- Once the CoCl2 has completely dissolved, carefully pour the solution into a clean container, such as a reagent bottle or a volumetric flask.
- Label the container with the concentration (0.150M CoCl2) and any other necessary information.
And that's it! You have successfully prepared a 250mL solution of 0.150M CoCl2 from solid CoCl2 and distilled water.
To prepare a 250mL, 0.150M solution of CoCl2 from solid CoCl2 and distilled water, you can follow the following steps:
Step 1: Calculate the amount of CoCl2 needed.
- Determine the molecular weight of CoCl2. (Cobalt has a atomic weight of 58.93 g/mol, and chlorine has an atomic weight of 35.45 g/mol.)
- CoCl2 has one cobalt atom and two chlorine atoms, giving it a molecular weight of 129.84 g/mol.
- Multiply the molecular weight by the desired molarity (0.150M) and the desired volume (250mL) to calculate the mass needed.
- (0.150 mol/L) x (0.250 L) x (129.84 g/mol) = 4.8736g of CoCl2
Step 2: Weigh the appropriate amount of CoCl2.
- Using an analytical balance, weigh out approximately 4.875g of CoCl2 solid.
Step 3: Dissolve the CoCl2 in distilled water.
- Pour the weighed CoCl2 solid into a clean and dry 250mL beaker.
- Add distilled water to the beaker and stir gently to dissolve the CoCl2. Start with a small amount of water and add more as necessary until the CoCl2 is completely dissolved.
- Ensure the solution is thoroughly mixed.
Step 4: Adjust the final volume.
- Transfer the solution into a 250mL volumetric flask, if available.
- Otherwise, transfer the solution into a graduated cylinder and add distilled water until the solution reaches the 250mL mark. Ensure the solution is thoroughly mixed.
Step 5: Verify the concentration.
- Use a colorimeter or a spectrophotometer to verify the molarity of the solution. CoCl2 solutions exhibit a specific color, and the absorbance or transmittance can be used to verify the concentration.
Note: It is essential to wear appropriate personal protective equipment, such as gloves and safety goggles, when handling chemicals. Adhere to all safety precautions and guidelines provided by your institution or laboratory.