1. Solutions Chapter 13 & 14

2. Solution  A uniform mixture that may contain solids, liquids, or gases  Also called a homogeneous mixture  Composed of a solute & solvent Solute: substance that dissolves Solute: substance that dissolves Solvent: dissolving medium Solvent: dissolving medium The most common solvent is water. SOLUTE + SOLVENT  SOLUTION

4. Solubility  The maximum amount of solute that will dissolve in a given amount of solvent  Solubility INCREASES as temp increases  Solubility DECREASES as pressure increases  Solubility INCREASES as surface area increases

5. Solutions…  Saturated solution: contains the maximum amount of dissolved solute for a given amount of solvent  Unsaturated solution: contains less dissolved solute than a saturated solution  Supersaturated solution: contains more dissolved solute than a saturated solution

6. A substance that dissolves in a substance is soluble. Ex. Sugar is soluble in water A substance that does not dissolve in a solvent is insoluble. Ex. Sand is insoluble in water

7. Two liquids that are soluble in each other are miscible. Ex. Water & acetic acid are miscible Two liquids that are insoluble in each other are immiscible. Ex. Oil & vinegar are immiscible

8. Concentration: a measure of how much solute is dissolved in a solution Concentrated solution: contains a large amount of solute Dilute solution: contains a small amount of solute

9. Expressing Concentration  Some common ways to express concentration are: Percent by mass Percent by mass Percent by volume Percent by volume Molarity Molarity Molality Molality

10. Percent by mass  Describes solutions in which a solid is dissolved in a liquid % by mass= mass of solute x 100 mass of solution mass of solution Mass of solution= mass of solute + mass of solvent Mass of solution= mass of solute + mass of solvent

11. Percent by volume  Describes solutions in which both solute & solvent are liquids % by volume= volume of solute x 100 % by volume= volume of solute x 100 volume of solution volume of solution

12. Problem Find the percent by mass of a solution containing 50g of NaCl dissolved in 100g of water.

13. Molarity Molarity (M)= moles of solute Molarity (M)= moles of solute liter of solution liter of solution

14. Problem You have 3.50L of solution that contains 90.0g of sodium chloride, NaCl. What is the molarity of the solution?

15. Dilution  A concentrated solution can be diluted by adding more solvent to the solution. M 1 V 1 = M 2 V 2 M 1 V 1 = M 2 V 2

16. Problem What volume is needed to dilute 3L of a 12M HCl solution to 2M HCl?

17. Molality Molality (m)= moles of solute Molality (m)= moles of solute kg of solvent kg of solvent

18. Problem A solution was prepared by dissolving 17.1g of sucrose (table sugar, C 12 H 22 O 11 ) in 125g of water. Find the molality of this solution.

19. Colligative properties  Solutes affect some of the physical properties of their solvents. These properties are called colligative properties. Adding a solute to a solvent LOWERS the vapor pressure. Adding a solute to a solvent LOWERS the vapor pressure. Adding a solute to a solvent RAISES the boiling point. Adding a solute to a solvent RAISES the boiling point. Adding a solute to a solvent LOWERS the freezing point. Adding a solute to a solvent LOWERS the freezing point.