1. Dilutions

2. Calculate the new concentration of a diluted solution.
Calculate the volume of a stock solution needed to prepare a new solution.
Calculate the concentration of a solution formed by combining two solutions of the same solute.

3. Moles of solute remains unchanged.
Labs buy concentrated solutions to save storage space - stock solutions.
To dilute a solution means to add more solvent to small volume of stock without adding more solute.
Moles of solute remains unchanged.
moless = molesd

4. moless
molesd

5. moless = molesd M = moles L C1V1 = C2V2
Where: C1 is the initial concentration (stock)
V1 is the initial volume of solution (stock)
C2 is the concentration after dilution
V2 is the volume after dilution in L

6. If 500. 0 mL of water is added to 300. 0 mL of a 0
If mL of water is added to mL of a mol/L solution of NaCl, what is the new concentration? C1 V1 = C2 V2
V2 = = mL
(0.100)
(0.300) = M C2
(0.800)

7. What is the concentration of the stock solution if 50
What is the concentration of the stock solution if 50.0 mL of the stock is diluted to make mL of a M solution? C1 V1 = C2 V2
(0.400)
(0.220)
1.76 mol/L C1 =
(0.0500)

8. How much water must be added to 25. 0 mL of a 1
How much water must be added to 25.0 mL of a 1.00 M stock solution of NaOH to make a M solution? C1 V1 = C2 V2
(1.00)
(0.0250) = V2
0.250 L
(0.100)
0.250 L – L = L

9. To prepare a diluted solution:
Determine the volume of stock solution needed.
Add half of the volume of water to the beaker.
Add the stock solution.
Add remaining water to the total volume and mix.

10. Total moles CFinal = Total volume (C1V1 + C2V2 + …) CFinal =
Mixing two or more solutions having the same solute, but different concentrations: =
CFinal
Total volume
Total moles =
(C1V1 + C2V2 + …)
CFinal
(V1 + V2 + …)

11. = 0.165 M (C1V1 + C2V2) CFinal = (V1 + V2 )
450.0 mL of a M NaCl solution is mixed with 125 mL of a M NaCl solution. =
(C1V1 + C2V2)
CFinal
(V1 + V2 ) =
(0.150)(0.450) + (0.220)(0.125) CF
( )
= M

12. A diluted solution has the same number of moles
of solute as the given stock, but a new volume.
Since the moles of solute remains the same, the
dilution equation is C1V1 = C2V2
Mix two or more solutions containing the same
solute - use the equation