1. Concentration = # of moles volume (L) V = 1000 mL V = 1000 mL
n = 8 moles
[ ] = 32 molar
V = 1000 mL
V = 1000 mL
V = 5000 mL
n = 2 moles
n = 4 moles
n = 20 moles
Concentration = 2 molar
[ ] = 4 molar
[ ] = 4 molar

2. Making a Dilute Solution
remove
sample
moles of
solute
initial solution
same number of
moles of solute
in a larger volume
mix
Making a Dilute Solution
diluted solution
Timberlake, Chemistry 7th Edition, page 344

3. Dilution
Preparation of a desired solution by adding water to a concentrate.
Moles of solute remain the same.

4. Dilution GIVEN: M1 = 15.8M V1 = ? M2 = 6.0M V2 = 250 mL WORK:
What volume of 15.8M HNO3 is required to make 250 mL of a 6.0M stock solution?
GIVEN:
M1 = 15.8M
V1 = ?
M2 = 6.0M
V2 = 250 mL
WORK:
M1 V1 = M2 V2
(15.8M) V1 = (6.0M)(.250L)
V1 = .095 L of 15.8M HNO3

5. It’s Your Turn To Try It Out!
Pretend you are doing a lab experiment that requires 3 L of a 0.5 M solution of HCl. Your stock solution is 10 M. How much stock solution do you need to add to water to make the needed solution? 
M1 = 10 M V1 = ? It is the unknown. M2 = 0.5 M V2 = 3 L 
Set up your equation. M1V1 = M2V2

6. How Did We Solve?
Rearrange the equation to solve for V1. V1 = M2V2 / M1
Fill in your known values and solve. V1 = (0.5 M)(3 L) / 10 M V1 = 0.15 L 
So you need to add 0.15 L of stock solution to water to make 3 L of diluted solution.

7. Safety: “Do as you oughtta, add the acid to the watta!”