Dilutions

Dilution is the process of decreasing the concentration by adding a solvent (usually water)
the amount of solute does not change (n1=n2), but the concentration does change!

Because concentration is mol/L we can write:

C= n/C, n= CV, and V= n/C
n=  number of moles, v= volume in litres


So we can use:

C1V1= C2V2
C1V1 is the intial concentration and volume
C2,V2 is the final concentration and volume


Here are some examples to follow by:


Example 1) A 30.0 mL of 11.9 M of Hydrochloric Acid is diluted to a final volume of 30 mL. What is the concentration of the new solution?


C1V1= C2V2


(11.9mol/L)(.03L)= C2 (0.3L)
.357 mol = C2 (0.3L)
C2= 1.19 M


Example 2) 100 mL of 0.330 M Li2CO3 is added to 600 mL 0.125 M Li2Co3. Determine the [Li2Co3]


0.10 L x (0.330 mol/L) = 0.033 mol/L

0.60 L x (0.125 mol/L) = 0.075 mol/L

0.033 mol + 0.075 mol = 0.108 mol

Take your volumes (100 mL + 600 mL) Add them together then convert it into Liters.


0.108 mol/ 0.7L
= 0.154 M




Example 3) If 250 mL of water are added to 50.0 mL of 1.00 M BaCo3, what will the final concentration be?

(1.00 mol/L) (.05 L) = C2 (.25L)
0.05 mol = C2(0.25 L)
C2 = 0.2 M

Try some Dilution questions!!