You are given a 500 mL stock solution of 10%CaCl2 and are askes to prepare a 50 mL solution of .5% CaCl2. How would you prepare it? Please show work
Use the dilution formula.
%1*mL1 = %2*mL2
10*mL1 = 0.5*50
Solve for mL1 of the 10% stock solution, pipet that quantity into a 50 mL volumetric flask, add DI H2O to the mark, mix thoroughly, stopper and viola!
To prepare a 50 mL solution of 0.5% CaCl2 from a 500 mL stock solution of 10% CaCl2, you can follow these steps:
1. Determine the amount (in mL) of the 10% CaCl2 stock solution needed to make the desired 0.5% CaCl2 solution using the equation:
(Concentration of stock solution x Volume of stock solution) = (Concentration of desired solution x Volume of desired solution)
Let's plug in the values we know:
(10% x Vstock) = (0.5% x 50 mL)
0.1Vstock = 0.005 x 50
0.1Vstock = 0.025
Now, divide both sides of the equation by 0.1 to solve for Vstock:
Vstock = 0.025 / 0.1
Vstock = 0.25 mL
Therefore, you will need to take 0.25 mL of the 10% CaCl2 stock solution.
2. Measure 0.25 mL of the 10% CaCl2 stock solution using a graduated pipette or syringe.
3. Transfer the measured volume of the stock solution to a container, such as a beaker or flask.
4. Add distilled water to the container to bring the total volume up to 50 mL. This will dilute the stock solution to the desired concentration of 0.5% CaCl2.
5. Mix the solution well to ensure thorough mixing and homogeneity.
That's it! You have successfully prepared a 50 mL solution of 0.5% CaCl2 from the given 500 mL stock solution of 10% CaCl2.
To prepare a 50 mL solution of 0.5% CaCl2 from a 10% stock solution of CaCl2, you can follow these steps:
Step 1: Determine the amount of CaCl2 needed from the stock solution.
Since the desired solution concentration is 0.5% CaCl2 and the volume needed is 50 mL, we can calculate the amount of CaCl2 needed using the formula:
Amount of CaCl2 needed = (Desired concentration / Stock concentration) x Volume needed
Amount of CaCl2 needed = (0.5% / 10%) x 50 mL
Amount of CaCl2 needed = (0.005 / 0.1) x 50 mL
Amount of CaCl2 needed = 0.05 x 50 mL
Amount of CaCl2 needed = 2.5 mL
Therefore, you will need to measure out 2.5 mL of the 10% CaCl2 stock solution.
Step 2: Calculate the volume of solvent needed.
Since the total volume of the desired solution is 50 mL and we already have 2.5 mL of the stock solution, we need to add a solvent (usually water) to make up the remaining volume.
Volume of solvent needed = Total volume needed - Volume of stock solution
Volume of solvent needed = 50 mL - 2.5 mL
Volume of solvent needed = 47.5 mL
So, you will need to add 47.5 mL of solvent to the 2.5 mL of the stock solution to prepare the desired 50 mL solution of 0.5% CaCl2.
Therefore, the final steps are to measure out 2.5 mL of the 10% CaCl2 stock solution and then add 47.5 mL of the solvent (like water) to make a total volume of 50 mL.