1. Solutions Chemistry 5th & 8th Hall ©Hall2010

2. Solutions Solution –Homogenous mixture containing 2 or more substances called solute and solvent Solute –Substance being dissolved Solvent –Dissolving medium Example –Salt into Water

3. Solutions Vocabulary Soluble –Substance that dissloves in a solvent –E.g. salt into water, sugar into water Insoluble –Substance that does not dissolve into water –E.g. sand into water Immiscible –2 liquids that are not soluble with each other –E.g. oil/water, oil/vinegar Miscible –2 liquids that do dissolve into each other –E.g. antifreeze, water/vinegar

5. Solvation To form a solution, solute particles must separate. Solvation is the process of surrounding solute particles with solvent particles to form a solution

6. Ionic Compounds Water molecules are polar and in constant motion When an ionic compound is placed in water, the water molecules collide with the ionic crystal until entire crystal dissolves. Table salt into water

7. Molecular Compounds Like ionic, but the molecules are much bigger Sugar C 12 H 22 O 11 into water

8. Factors that Affect Rate of Solvation Increase in collisions 1.Agitation 2.Increase in surface area of solute 3.Increase Temperature of solvent

9. Heat of Solution During solvation, solute must separate into particles Solvent particles also must move apart Energy is required to break attractive forces with in solvent and solute When solute and solvent particles mix, they are attracted to each other and energy is released (exothermic) Heat of Solution is the overall change in energy

10. Solubility Maximum amount of solute that will dissolve in a given amount of solvent at a specific Temperature and Pressure. –Usually in Example: 10g of NaCl in 100g of H 2 O

11. Saturation Saturated –Max amount of dissolved solute for a given amount of solvent at a specific T & P Unsaturated –Contains less dissolved solute for a given T & P than a saturated solution

12. Factors that affect Saturation Temperature –Increase in temperature=more soluble –Not true for gases though Supersaturation –Contains more dissolved solute than a saturated solution at the same Temperature To make, saturate a solution at high temperature and allow to cool slowly If a tiny amount of solute is added or the solution is agitated, a precipitate will form

14. Pressure and Solubility Affects gases Solubility Pressure Henry’s Law –At a given temperature, solubility (S) of a gas in a liquid is directly proportional to the pressure (P) of gas above the liquid

15. Henry’s Law Example If 0.85g of a gas at 4.0 atm of pressure dissolves in 1.0L of water at 25  C, how much will dissolve in 1.0L of water at 1.0 atm of pressure and the same temperature S 1 = 0.85 g/L P 1 = 4.0 atm S 2 = ? g/L P 2 = 1.0 atm

16. Henry’s Law Example S 1 = 0.85 g/L P 1 = 4.0 atm S 2 = ? g/L P 2 = 1.0 atm Work problem 2 on pg. 461

17. Concentration Percent by Mass Whether it is mass or volume, the solution is the solvent + the solute Example: Mass of Solute= 3.6 g Mass of Solvent = 100.0 g Find mass of solution first Then Percent by Mass Now you work 8,9,10 and worksheet is homework

18. Concentration Percent by Volume Example: Volume of solute= 35 mL Volume of solvent = 115 mL Now you do problems 11 and 12 on page 464 Find volume of Solution Next find the Percent by Volume

19. Molarity Number of Moles of solute dissolved per liter of solution Know your UNIT CONVERSIONS and HOW TO GO FROM GRAMS TO MOLES

20. Molarity Example A 100.5 mL intravenous solution contains 5.10 g glucose (C 6 H 12 O 6 ). What is the molarity of this solution? Molar mass of glucose is 180.16 g/mol.

21. Molarity Example 2 What is the molarity of a bleach solution containing 9.5 g of NaOCl per liter of bleach? First change grams to moles Next, find molarity. The volume of the solution is 1 L.