1. Properties of Solutions

2. Changes In State

3. A Review of Matter Types of matter Types of matter Pure substances Pure substances –Elements – cannot be broken down by chemical means means –Compounds – two or more elements combined in definite proportions definite proportions Mixtures Mixtures –Homogeneous – evenly mixed, uniform throughout –Heterogeneous – unevenly mixed, varied composition

4. Increasing Surface Area Increases Dissolution

5. What is a Solution? Homogeneous mixture of substances in the same state. Homogeneous mixture of substances in the same state. A solution may be; A solution may be; –A solid solid. Ex. Zn + Cu  brass (alloy) –Gas gas. Ex. Air. –Liquid liquid. Ex. alcohol + water –And, most familiar to you, a substance, usually a solid, dissolved in water.Ex. NaCl + water.(sea water)

6. Components of a Solutions A solute is the substance being dissolved. A solute is the substance being dissolved. The solvent is the substance that exists in the greater amount, into which the solute is mixed. The solvent is the substance that exists in the greater amount, into which the solute is mixed. Ex. In sea water, salt is the solute, while water is the solvent. Ex. In sea water, salt is the solute, while water is the solvent. Water’s properties make it a universal solvent. Water’s properties make it a universal solvent.

7. The Secret To Waters Dissolving Power is it’s Polarized Nature The polar water molecules surround the solute molecules, forming H-bonds and dipole attractions

8. Aqueous Solutions Solutions of a substance dissolved in water are termed aqueous and are written as follows; Solutions of a substance dissolved in water are termed aqueous and are written as follows; NaCl (s)  Na + (aq) + Cl - (aq) (where s = solid, aq = aqueous, and g = gas) NaCl (s)  Na + (aq) + Cl - (aq) (where s = solid, aq = aqueous, and g = gas) The particles of a homogeneous aqueous solution are very small, will not settle and will pass through a filter. The particles of a homogeneous aqueous solution are very small, will not settle and will pass through a filter.

9. Mixtures Can Be Separated

10. Properties of Mixtures Light will pass directly through a solution. Light will pass directly through a solution. The light beam will not be visible in the body of the solution. The light beam will not be visible in the body of the solution. Light will be scattered by the larger particles of heterogeneous solutions. Light will be scattered by the larger particles of heterogeneous solutions. This is called the Tyndall Effect, after the scientist who discovered it. This is called the Tyndall Effect, after the scientist who discovered it.

11. Colloids and Suspensions Scatter Light. Solutions Do Not.

12. Summary of Solution Properties Aqueous solutions are homogeneous mixtures Aqueous solutions are homogeneous mixtures They are clear and do not disperse light. They are clear and do not disperse light. Can have color (ex. CuSO 4 is blue). Can have color (ex. CuSO 4 is blue). Particles will not settle when left standing. Particles will not settle when left standing. Particles pass readily through a filter. Particles pass readily through a filter.

13. Solubility Ability of a substance to dissolve in another substance. Ability of a substance to dissolve in another substance. “Like dissolves like.” “Like dissolves like.” –Polar molecules dissolve in polar substances –Non-polar (lipids, oils) dissolve in non-polar. All materials do not dissolve in equal concentrations. All materials do not dissolve in equal concentrations.

14. Solubility Highly soluble materials are said to be soluble or miscible. Highly soluble materials are said to be soluble or miscible. Materials that dissolve very little are said to be insoluble or immiscible. Materials that dissolve very little are said to be insoluble or immiscible. A material dissolves because the attraction of the solvent molecules is greater than the attractive force holding the solute molecules together. A material dissolves because the attraction of the solvent molecules is greater than the attractive force holding the solute molecules together. Insoluble materials have a greater affinity for their own molecules. Insoluble materials have a greater affinity for their own molecules. These last 2 points is why oil pools together in water These last 2 points is why oil pools together in water

15. Temperature and Pressure Solubility is relative to changing temperature. Solubility is relative to changing temperature. Generally, solubility increases with increasing temperature. Generally, solubility increases with increasing temperature. Pressure has NO EFFECT on the solubility of solids and liquids (that compressibility thing again) ONLY GASES. Pressure has NO EFFECT on the solubility of solids and liquids (that compressibility thing again) ONLY GASES. Gases behave oppositely, they are more soluble at higher pressure and lower temperature (open a warm seltzer bottle and a cold one at the same time). Gases behave oppositely, they are more soluble at higher pressure and lower temperature (open a warm seltzer bottle and a cold one at the same time).

16. Gas Mixtures React Opposite to Liquids in Terms of Pressure and Temperature

17. Solubility Graphs Solubility Graphs We can look at a graph of solubility curves to determine how much solute can dissolve in a specific quantity of solvent. We can look at a graph of solubility curves to determine how much solute can dissolve in a specific quantity of solvent. We need to know; We need to know; –Which solute –What temperature See reference tables F and G. See reference tables F and G.

18. Table F Guidelines for solubility (Table F) Guidelines for solubility (Table F) –Table F is broken down into Ionic compounds that are soluble. Try learning the exceptions, there are fewer and you’ll know the rules by default. There are many Ionic compounds that are insoluble and many exceptions (use the table). There are many Ionic compounds that are insoluble and many exceptions (use the table).

20. Table G Graph of solubility curves Graph of solubility curves Broken down into; Broken down into; –X axis = Temperature in Celsius –Y axis = amount of solute per 100g H 2 O. How to read graph How to read graph –Trace given info, grams or °C, along curve of X and Y axis to find desired data point for given solute.

22. Saturation There is an upper limit to how much solute a given solvent can hold at a certain temperature. There is an upper limit to how much solute a given solvent can hold at a certain temperature. When holding the maximum amount of solute the solution is said to be saturated. When holding the maximum amount of solute the solution is said to be saturated. When a solution is saturated the addition of any more solute will cause a precipitate to form. When a solution is saturated the addition of any more solute will cause a precipitate to form. Ex. Have you ever found un-dissolved substance on the bottom of your coffee or ice tea? Ex. Have you ever found un-dissolved substance on the bottom of your coffee or ice tea?

23. Using Table G (solubility curves) To Predict Solubility of Substances Find KNO 3 (potassium nitrate) in table G. Find KNO 3 (potassium nitrate) in table G. At approximately 32°C, 100 grams H 2 0 can hold a maximum of ~50grams of KNO 3. It is saturated at this mass and temperature. At approximately 32°C, 100 grams H 2 0 can hold a maximum of ~50grams of KNO 3. It is saturated at this mass and temperature. If the temperature was raised to 50°C, 100g of solvent could hold up to ~83 grams of KNO 3. If the temperature was raised to 50°C, 100g of solvent could hold up to ~83 grams of KNO 3. One could add an additional 33 grams of solute to re-saturate the solution. One could add an additional 33 grams of solute to re-saturate the solution. If you do not add more solute, the solution would be called unsaturated. If you do not add more solute, the solution would be called unsaturated.

24. Supersaturation This occurs when a solution is heated, saturated and then slowly cooled, creating a new saturation point. This occurs when a solution is heated, saturated and then slowly cooled, creating a new saturation point. The solution maintains it’s homogeneous appearance. The solution maintains it’s homogeneous appearance. Supersaturated solutions are very unstable. Supersaturated solutions are very unstable. Addition of a single crystalline molecule will cause the solution to form a precipitate. Addition of a single crystalline molecule will cause the solution to form a precipitate.

25. Determining Saturation Visual inspection: Does the solution contain un- dissolved particles? Visual inspection: Does the solution contain un- dissolved particles? Addition of more solid solute: Addition of more solid solute: 1.Does the solid fall to the bottom? Yes  solution is saturated Yes  solution is saturated No  solution is not saturated No  solution is not saturated 2.Does a precipitate form (material comes out of solution)? Yes  solution is supersaturated Yes  solution is supersaturated No  return to (1) No  return to (1)

26. Concentration of Solutions Compositions of homogeneous mixtures can vary. Compositions of homogeneous mixtures can vary. Two terms are commonly used; Two terms are commonly used; –Dilute –Concentrated The above terms are relative, that is, they are not very precise and tell little about how much solute is present. The above terms are relative, that is, they are not very precise and tell little about how much solute is present. More precise terms are; molarity, % mass, % volume & ppm (parts per million). More precise terms are; molarity, % mass, % volume & ppm (parts per million).

27. Molarity Molarity is the number of moles of solute per liter of solution. Molarity is the number of moles of solute per liter of solution. M = # mol solute L solution L solution Molarity can be used as a conversion factor to find Volume and # of mols. Molarity can be used as a conversion factor to find Volume and # of mols. M (mol/L) x V (L) = # of mol

28. Percent by Mass Mass of a certain ingredient divided by the total mass. Mass of a certain ingredient divided by the total mass. % Mass = Mass of part x 100 Mass of Whole Mass of Whole

29. Parts Per Million PPM is used when very small amounts are present. PPM is used when very small amounts are present. Generally used to report acceptable levels of toxins, pollutants, poisons or other trace amounts of substances. Generally used to report acceptable levels of toxins, pollutants, poisons or other trace amounts of substances. PPM = grams of solute x 10 6 PPM = grams of solute x 10 6 grams of solution grams of solution

30. Dilution The process of preparing a less concentrated solution from a more concentrated one. The process of preparing a less concentrated solution from a more concentrated one. M 1 V 1 = M 2 V 2 Where M 1 and M 2 equal the old and new molarities and… Where M 1 and M 2 equal the old and new molarities and… V 1 and V 2 equal the old and new volumes. V 1 and V 2 equal the old and new volumes.