You begin with 10 ml of 2% acetic acid, and you add 90 ml of water. We will call the resulting solution "dilution#1". What is its concentration?
You then repeat the dilution exactly, using 10ml of Dilution #1, adding 90 ml of water. We will call the resulting solution "Dilution #2". What's it concentration?
You then repeat the dilution exactly, using 10 ml of Dilution #1, adding 90 ml of water. We will call the resulting solution "Dilution#3" What's it concentration?
WHat is this progression called?
To find the concentration of a solution after dilution, we need to understand the concept of dilution and how it affects the concentration of a solute.
Dilution is the process of reducing the concentration of a solute in a solution by adding more solvent (typically water) to it. To calculate the concentration of a diluted solution, we use the equation:
C1V1 = C2V2
Where:
C1 = initial concentration of the solute
V1 = initial volume of the solution
C2 = final concentration of the solute
V2 = final volume of the solution
Let's apply this principle to your question:
1. Dilution #1:
You start with 10 ml of 2% acetic acid and add 90 ml of water. Since you are diluting 10 ml of the original solution with a total volume of 100 ml, the final volume is 100 ml.
Using the dilution equation, we can calculate the final concentration (C2):
(2%)(10 ml) = C2(100 ml)
Simplifying the equation, we get:
20 = C2(100)
C2 = 0.2%
Therefore, Dilution #1 has a concentration of 0.2% acetic acid.
2. Dilution #2:
Now you take 10 ml of Dilution #1 and add 90 ml of water. Using the same equation:
(0.2%)(10 ml) = C2(100 ml)
Simplifying:
2 = C2(100)
C2 = 0.02%
Dilution #2 has a concentration of 0.02% acetic acid.
3. Dilution #3:
Again, you start with 10 ml of Dilution #1 and add 90 ml of water:
(0.2%)(10 ml) = C2(100 ml)
Simplifying:
2 = C2(100)
C2 = 0.02%
Dilution #3 also has a concentration of 0.02% acetic acid.
The progression you described, where you repeatedly dilute a solution using the same ratio, is called serial dilution. In this case, you are performing a 1:10 serial dilution, where each step involves diluting the solution ten-fold.