1. Molarity and Dilution
Solution Chemistry

2. CONCENTRATION
Concentration- a measure of the amount of solute that is dissolved in a given amount of solvent.
QUALITATIVE: (tells about the quality, not a #)
Concentrated solution – high amt of solute
Dilute solution – low amt of solute
QUANTITATIVE: (tells an actual amt)
Molarity (M) – number of moles of solute / L of solution

3. EXAMPLE PROBLEMS
A salt solution has a volume of 250 mL and contains 0.70 mol of NaCl. What is the molarity of the solution?
How many grams of CaCl2 are needed to make 250 mL of 2.0 M CaCl2?

4. DILUTIONS M1V1 = M2V2 Diluting a Solution
You can make a solution less concentrated by adding more solvent
The # of moles of solute DOES NOT CHANGE when the solution is diluted
Molarity (M) = # moles solute / # Liters solvent
moles solute = M x L
number of moles stays the same so:
M1V1 = M2V2

5. EXAMPLE PROBLEMS
How would you prepare 100mL of 0.40 M MgSO4 from a stock solution of 2.0M MgSO4?
Your experiment requires 5 mL of 1.0M KOH. However, you have 1 L of 0.5 M KOH. Can you prepare the required solution by diluting what you have? Explain.