CHEM 121 Chapter 8 Winter 2015

Mixtures Heterogeneous mixture: Homogeneous mixture: Solution: Colloid:

Solutions Solution = Solute Solvent

Types of Solutions Colloids: Suspensions:

Solubility Most ionic and polar substances __________________ Most nonpolar substances _______________________ ___________ can be endothermic or exothermic

Solvation - - - + + + - - - + + + - - - + + + - - - + + + Example: NaCl - - - + + + - - - + + + - - - + + + - - - + + +

Solubility Amount of solute that can dissolve in a given amount of solvent Solubility rules p. 247

Temperature and Solubility As T increases…. Fig. 7.3

Pressure and Solubility

What dissolves? Gases form solutions easily Solids and liquids:

Concentration Volume Percent = Weight/Volume Percent =

3-minute Practice The amount of alcohol in a bottle of wine is labeled 13.5% (v/v). How much alcohol is in the entire 750. mL bottle?

ppm and ppb Parts per million = =

Molarity Molarity (M) = What is the molarity of the solution created when you dissolve 2.5 g of NaOH in 100. mL of solution?

3-minute Practice How many grams of NaOH would you have to dissolve in water to make 100. mL of a 1.0 M solution?

Dilution Add more water: Volume? Concentration? Amount of solute? Number of moles of solute?

3-minute Practice Suppose you have a 1.0 M NaOH solution, but you want a 200. mL of a 0.25 M NaOH solution. How would you make this solution?

Aqueous Reactants You have 250 mL of 1.0 M NaOH. How many moles NaOH? How much 0.2 M H2SO4 solution would you need to completely react the NaOH?

5-minute Practice You have: 200. mL of 2.0 M H2SO4 and 500. mL of 1.5 M NaOH How much water (g) can you make? Hints: Go to moles of each Determine which is limiting!

Electrolytes Electrolyte: Nonelectrolytes:

Colligative Properties Properties that change based on dissolved concentration Boiling point elevation: Freezing point depression: Osmotic pressure:

5-minute practice You fill a pot with 320. g of NaCl and enough water to total 1.50 L of solution. What is the boiling point of this solution?

Membranes Semipermeable:

Osmosis Osmosis:

Dialysis: