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SOLUTIONS

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  1. SOLUTIONS Chapter 15

  2. Solution = homogeneous mixture • Solute = gets dissolved (minor component) • Solvent = dissolving agent (major component)

  3. A substance that dissolves in a solvent is said to be soluble. These two substances are miscible.

  4. A substance that does not dissolve in a solvent is insoluble. These two substances are immiscible.

  5. Page 454 in Book (See Table 15-1, p.454)

  6. Water is an excellent solvent. It is the “universal solvent.” Solutions made with water are called aqueous solutions. Movie:

  7. Water is polar and dissolves many ionic and polar substances.

  8. Solvation = the process of surrounding solute particles with solvent particles to form a solution. Solute particles must separate from one another and the solute and solvent particles must mix.

  9. Ionic compounds dissolves in waterbecause they have charges (polar). Animation: Dissolving table salt

  10. “Like dissolves like.” • Polar solutes dissolve in polar solvents • Nonpolar solutes dissolve in nonpolar solvents

  11. Polar covalent compounds dissolve in water; non-polar compounds do not dissolve in water.Sugar (glucose) is polar and dissolves in water.

  12. Factors that affect rate of solvation • Stirring the mixture • Increasing the surface area of the solute • Increasing the temperature of the solvent

  13. Solubility = maximum amount of solute that will dissolve in a given amount of solvent at a specified temperature and pressure • Saturated = maximum amount of solute is dissolved • Unsaturated = more solute can be dissolved • Supersaturated = contains more dissolved solute than a saturated solution at the same temperature.

  14. Factors that affect solubility • Increased Temperature – solubility of solids increases; solubility of gases decreases. • Increased Pressure – solubility of gases increases. (This process is called aeration) • Henry’s Law –at a given temperature, the solubility (S) of a gas in a liquid is directly proportional to the pressure (P) of the gas above the liquid.

  15. Ch.15.2- Solution Concentration • The concentration of a solution is a measure of how much solute is dissolved in a specific amount of solvent or solution. solute or solute solvent solution (solution = solute + solvent)

  16. Expressing Concentration • Concentration may be described qualitatively as concentrated or dilute.

  17. Concentration= solute or solute solvent solution

  18. Percent by Mass (p.463 #8) • What is the percent by mass of NaHCO3 in a solution containing 20 g NaHCO3 dissolved in 600 mL H2O? • Density of H2O = 1.00 g/mL • % by mass = 20 g x 100 = 3.2% 620 g

  19. Percent by Mass (p.463 #9) • You have 1500.0 g of a bleach solution. The percent by mass of the solute sodium hypochlorite, NaOCl, is 3.62%. How many grams of NaOCl are in the solution? • % Mass = mass solute x 100 mass solution 3.62 = x g X 100 1500.0 g x = 54.3 g NaOCl

  20. Percent by Volume (p.464 #12) • If you have 100.0 mL of a 30.0% aqueous solution of ethanol, what volumes of ethanol and water are in the solution? • % Volume = volume of solute x 100% volume of solution 30.0 % = x mL x 100 100.0 mL x = 30 mL ethanol 70 mL water

  21. Molarity (p.465 #14) • What is the molarity of an aqueous solution containing 40.0 g of glucose (C6H12O6) in 1.5 L of solution? • 1 mole C6H12O6 = 180.16 g • 40.0 g C6H12O6 x 1 mole = 0.222 mol 180.16 g • Molarity = 0.222 mol = 0.15 M C6H12O6 1.5 liter

  22. Molarity (p.465 #15) • What is the molarity of a bleach solution containing 9.5 g NaOCl per liter of bleach?

  23. Molarity (p.465 #16) • Calculate the molarity of 1.60 L of a solution containing 1.55 g of dissolved KBr.

  24. Molarity (p.466 #17) • How many grams of CaCl2 would be dissolved in 1.0 L of a 0.10 M solution of CaCl2?

  25. Molarity (p.466 #18) • A liter of 2M NaOH solution contains how many grams of NaOH?

  26. Molarity (p.466 #19) • How many grams of CaCl2should be dissolved in 500.0 mL of water to make a 0.20M solution of CaCl2?

  27. Molarity (p.466 #20) • How many grames of NaOH are in 250 mL of a 3.0M NaOH solution?

  28. Diluting Solutions- p.467 • In the laboratory, you may use concentrated solutions called stock solutions. • For example, concentrated hydrochloric acid (HCl) is 12 M. • You can dilute the stock solution by adding more solvent. • Would you still have the same number of moles of solute particles that were in the stock solution?

  29. Diluting Solutions- p.467 • Molarity (M) = moles solute liters solution • moles solute = Molarity x liters solution • Because the total number of moles of solute does not change during dilution, moles solute in stock solution = moles solute after dilution M1V1 = M2V2

  30. Diluting Solutions- p.468 #21 • What volume of a 3.00 M KI stock solution would you use to make 0.300 L of a 1.25 M KI solution?

  31. Diluting Solutions- p.468 #23 • If you dilute 20.0 mL of a 3.5 M solution to make 100.0 mL of solution, what is the molarity of the dilute solution?

  32. Molality- p.469 • Molality (m) = moles solute = moles solute kilogram solvent 1000 g solvent • What is the molality of a solution containing 10. 0 g Na2SO4 dissolved in 1000.0 g of water? • What is the molality of a solution containing 30.0 g of naphthalene dissolved in 500.0g of toluene?

  33. Mole Fraction- p.470

  34. Mole Fraction- p.470 #26 • What is the mole fraction of NaOH in an aqueous solution that contains 22.8% NaOH by mass?

  35. Mole Fraction- p.470 #27 • An aqueous solution of NaCl has a mole fraction of 0.21. What is the mass of NaCl dissolved in 100.0 mL of solution?

  36. Parts per million (ppm)

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