Molarity  Molarity = grams / molar mass / Liters  Liters = grams / molar mass/ Molarity  Grams = Molarity x Liters x molar mass

Molarity  The higher the number the more concentrated  Which solution is more concentrated? 1 M3.5 M 0.5 M2.0 M

Molarity Review  What is the molarity of a solution containing 400 grams of lithium chloride in 500 mL of water?

Molarity Review  If you a 4.5 M solution with 35 g of NaCl, how many liters do you have?

Molarity Review  You need to prepare 800 mL of a 1.5 M solution of magnesium oxide. How many grams do you need?

Dilutions Section 15.2 Dilute = add more solvent Moles of solute do not change. Therefore… moles of solute before = moles of solute after M 1 V 1 = M 2 V 2

Dilutions Volume does not have to be in Liters Each side the equation must have the SAME VOLUME UNITS Molarity x mL = Molarity x mL or Molarity x L = Molarity x L

Dilutions Stock solution The original solution that gets diluted to get the desired concentration of the new solution

M 1 V 1 = M 2 V 2 1. How much stock solution do I need to prepare 500 mL of a new solution with a concentration of 4.5 M if the stock solution is 11.6 M?

M 1 V 1 = M 2 V 2 2. What volume of a 3 M KI solution would you use to make 0.3 L of a 1.25 M KI solution?

M 1 V 1 = M 2 V 2 3. How many milliliters of a 5 M H 2 SO 4 solution would you need to prepare 100 mL of a 0.25 M solution?

M 1 V 1 = M 2 V 2 4. If you dilute 20 mL of a 3.5 M solutions to make 100 mL solution, what is the molarity of the dilute solution?

M 1 V 1 = M 2 V 2 5. What is the molarity if 1279 g of K 3 PO 4 is dissolved in 4 L of water?

M 1 V 1 = M 2 V 2 6. If you dilute 50 mL of a 6 M solution to make 200 mL solution, what is the molarity of the new solution?

7. How many grams of magnesium sulfate would be dissolved in 1 L to make a 0.3 M solution?

8. If 0.65 g of a gas dissolves in 1 L of water at 2 atmospheres of pressure, how much will dissolve at 22 atmospheres of pressure?

15.3 Colligative Properties Colligative = “depends on the collection” Properties that depend on how many solute particles are present Does NOT depend on identity of solute

Vapor Pressure Lowering Vapor pressure = pressure created by particles going from liquid to gas inside a closed container If you add solute, not as much solvent can escape into the gas phase Pure solvent Solution

Boiling Point Elevation Boiling = liquid to gas The more solute added to a solution, the lower the vapor pressure and therefore the higher the boiling point Solution

A solvent has a boiling point of 200°C. When 10 grams of salt is dissolved in the solvent, what is the most likely new boiling point? a. 210°C b. 200°C c. 190°C

Freezing Point Depression Freezing = solvent particles moving into solid crystalline form Solute gets in the way of making crystals preventing the solvent from freezing. Lower temperature is needed to freeze

A solvent has a freezing point of 10°C. What is the most likely freezing point if 5 grams of salt is mixed with the solvent? a. 5°C b. 10°C c. 15°C

Osmotic Pressure Increase Osmosis-movement of water from low to high concentration. Goal is to balance the concentrations Osmotic Pressure Increases