1. Preparing a Molar Solution
How many grams of sucrose (C12H22O11) is needed to prepare one liter of a 1.50 M solution?
You’ll need the molar mass of sucrose:
1.5 mol g
_____________ X ___________ = 513 g / liter
1 liter mol

2. Preparing a Molar Solution
How many grams of sucrose (C12H22O11) is needed to prepare 100 mL of a 1.50 M solution?
1.5 mol g
_____________ X ___________ = 513 g / liter
1 liter mol
1 L g
100 mL X __________ X _____________ = 51.3 g
1000 mL L

3. Diluting Solutions
Many solutions (acids) come in a concentrated liquid form called a stock solution
To dilute this solution, you add more solvent (usually water or alcohol)
The amount of solute does not change, so the amount of solution SO
M1V1 = M2V2

4. Diluting Solutions
What volume in milliliters of 2.00M calcium chloride (CaCl2) would you use to make .50 L of .300 M calcium chloride solution?
.50 L X 1000 mL/1 L = 500 mL
M1V1 = M2V2
2.00M x V1 = .300M x 500 mL
V1 = .300M x 500 mL / 2.00M
V1 = 75 mL

5. Mole Fraction Another way to express concentration
Need to know the number of moles of solute and solvent
Abbreviated as X
Xa = mole fraction of solvent = na / na + nb
Xb = mole fraction of solute = nb / na + nb

6. Mole Fractions
What is the mole fraction of water in an HCl solution containing 62.5% water and 37.5% HCl by mass?
62.5 g x 1mol / g = 3.47 mol H2O
37.5 g x 1mol / g = 1.03 mol HCl
na / na + nb
3.47 mol H20 / 1.03 mol HCl mol H20
na = .771