How would you prepare

1. 100 ml of 0.20 M Ca(OH)2 from 0.50 M Ca(OH)2

To prepare 100 ml of 0.20 M Ca(OH)2 from 0.50 M Ca(OH)2, you need to dilute the 0.50 M solution. Dilution involves adding a solvent, usually water, to the concentrated solution to decrease its concentration.

Here's how you can calculate the amount of 0.50 M Ca(OH)2 solution and water you need for the dilution:

1. Use the formula for dilution: C1V1 = C2V2
C1 = initial concentration of the concentrated solution (0.50 M)
V1 = volume of the concentrated solution used for dilution (unknown)
C2 = final concentration of the diluted solution (0.20 M)
V2 = final volume of the diluted solution (100 ml or 0.100 L)

2. Substitute the given values into the formula:
(0.50 M)(V1) = (0.20 M)(0.100 L)

3. Rearrange the equation to solve for V1:
V1 = (0.20 M)(0.100 L) / (0.50 M)

4. Calculate V1:
V1 = 0.020 L or 20 ml

5. Since you need 100 ml (0.100 L) of the final solution, subtract V1 from the final volume:
Volume of water = Final volume - Volume of concentrated solution
Volume of water = 0.100 L - 0.020 L
Volume of water = 0.080 L or 80 ml

So, to prepare 100 ml of 0.20 M Ca(OH)2, you need to dilute 20 ml of the 0.50 M Ca(OH)2 solution with 80 ml of water.