1. Molar Concentration and Dilutions

2. How to make a solution Using a Volumetric Flask

3. molar concentration = moles volume (L) c = n _ V n c V

4. eg. What is the molarity of the CaCl2 in a solution made by dissolving and diluting 15.00g of CaCl2.6H2O to mL? CaCl2.6H2O(s)  CaCl2(aq) + 6H2O(l) ( Ca2+ + 2Cl- ) CaCl2 = CaCl2.6H2O = 15.00g x 1 mol L 219.1g = M
molar mass of CaCl2.6H2O

5. Simulations concentration:
dilution:

6. Dilution Calculations
n = c . V nconc = cconc . Vconc and ndil = cdil . Vdil but, if we add water to a concentrated solution to dilute it, the amount of solute (n) doesn’t change, only its concentration in the solution changes. So, nconc = ndil and cconc . Vconc = cdil . Vdil

7. c1V1 = c2V2 or c2 = c1V1 V2 another way to write this:
(You can leave your volumes in mL here because they will cancel each other out.)

8. Try:
If mL of M NaCl is added to mL of water, what is the resulting NaCl in the mixture?
V1 = mL
c1 = M
V2 = mL mL
= mL (total volume! )
c2 = ?
c2 = c1V1 V2
c2 = (0.500 M)(200.0 mL)
500.0 mL
c2 = M

9. Mixing 2 solutions (of the same stuff) each of a different concentration
(This is like diluting strong iced tea with weaker iced tea (or vice versa))
*Watch your significant figures
Treat this as two individual dilutions:
find the new concentration of each solution (based on the new total volume)
Then add them together to find the final concentration
Your final answer should be in between the two concentrations you started with

10. Final [NaCl] = c2 + c2 = 0.09375 M + 0.06250 M [NaCl] = 0.1563 M
Eg. If mL of M NaCl is mixed with mL of M NaCl, what is the final NaCl concentration?
Solution A V1 = mL C1 = M V2 = mL (= ) C2 = ? C2 = c1 V1 V2 C2 = (300.0 mL) (0.250 M) (800.0mL) C2 = M
Solution B V1 = mL C1 = M V2 = mL (= ) C2 = ? C2 = c1 V1 V2 C2 = (500.0 mL) (0.100 M) (800.0mL) C2 = M
Final [NaCl] = c2 + c2 = M M [NaCl] = M

11. Practice!! P. 102 # 78-94! Worksheet P.98 # 59, 61-65, 69-70
And empirical formula!