2. 1 Mixtures, Solutions, and Water Unit 7A

3. 2 Types of Mixtures Review: When we classified matter, we learned that mixtures can be classified as: Homogeneous (visually the same throughout) or Heterogeneous visually different throughout) What are some examples of each of these types of mixtures?

4. 3 Suspension: a heterogeneous mixture of 2 or more substances  Particles are large enough to settle out and can be separated by filtering i.e. – Muddy water

5. 4 Flour suspended in water (appears light blue because blue light is scattered off the flour particles to a greater extent than red light) Other examples: Chalk Dust suspended in the air Paint

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7. 6 Colloids: homogeneous mixture of 2 or more substances evenly blended into one another.  Substances never separate (settle out)

8. 7 What’s the difference between a solution and colloid? Colloids have larger particles that scatter light; Solutions have smaller particles that do not scatter the light Use the: Is fog a solution or colloid?

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11. 10 A solution is... Def. - A homogenous mixture of two or more substances NOT The Formation of a solution is a physical change …NOT a chemical change.

12. 11 Solute: the substance that is being dissolved Present in the smallest amountPresent in the smallest amount Solvent: component present in the largest amount (usually H 2 O).

13. 12 Types of Liquid Solutions Aqueous A solution with water as the solventTincture A solution with alcohol as the solvent

14. 13 Solution Concentration Refers to the amount of solute dissolved in a solvent 5 grams of salt in 100 grams of water dilute VS 35 grams of salt in 100 grams of water concentrated 100 g. 5 g 35 g

15. 14 Concentrated vs. Dilute A concentrated solution contains: Large amount of SOLUTE in a small amount of SOLVENT A dilute solution contains: Small amount of SOLUTEdissolved in a large amount of SOLVENT “from concentrate” SUMMARY

16. 15 Does a solution always have to a be liquid? NO!!

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18. 17 Solid into a Solid (alloy): two metals dissolved into one another. Solid into a Liquid: Salt dissolved in water. Gas into a Liquid: CO 2 dissolved (under pressure) into a coke.

19. 18 The air that we breathe is also a solution because it is made up of many different gases. 78.09% Nitrogen 20.95% Oxygen Argon, CO 2, and other trace gases The “solvent”

20. 19 Day 2 – Solubility Graphs

21. 20Dissolving Def: the process of creating a solution through the mixing of solute and solvent particles Can a solute be dissolved by any solvent? NO!! NO!!

22. 21Insoluble When a substance cannot be dissolved in a solvent... Oil water + = soluble The word soluble refers to solutes that CAN be dissolved in a particular solvent.

23. 22 The Exxon Valdez Oil Spill of 1989

24. 23Solubility A measure of how much solute can be dissolved in a solvent under certain conditions (i.e. – temp. & pressure) Example

25. 24 Limits of Solubility Supersaturated : Supersaturated : more solute has been dissolved than is normally possible Saturated: Saturated: the maximum amount of solute has been dissolved in the solvent Unsaturated: Unsaturated: more solute can be dissolved in the solvent A solution can be described as: http://boyles.sdsmt.edu/sup ersat/AlexanderOnly.asx

26. 25 Solubility Graphs Saturated Unsaturated

27. 26 Any point directly on the line = Saturated Any point below the line = Unsaturated Shows the relationship between temperature and solubility

28. 27 Dissolving Rate Def. – The amount of time required for a solvent to dissolve a particular solute “Speed of dissolving”

29. 28 Dissolving Rates (Solid in a Liquid & Gas in a Liquid)

30. 29 Three Factors Affecting Dissolving Rate of a Solid into a Liquid: 1.Temperature 2.Stirring 3.Surface Area

31. 30Temperature Increasing the temperature causes an increase in kinetic energy of the solid solute and liquid solvent particles As the particles move faster, they collide into each other more, thereby increasing the DISSOLVING RATE

32. 31Stirring Stirring also increases dissolving rate Stirring causes an increase in collisions between the particles in a solution

33. 32 Surface Area Def. – A measure of how much exposed area a substance has Breaking, crushing, etc. are ways to increase the Surface Area Increasing surface area allows more solute to come into contact with the solvent; increases dissolving rate VS.

34. 33 Pressure has the greatest effect on the solubility of a gas in a liquid! Depends on: 1. Pressure = solubility 2. Temperature= solubility 3. Stirring = solubility

36. 35Effervescence The escape of a gas from a liquid solution

37. 36 Day 4 – Water, Electrolytes, and Ionic Solutions

38. 37 Water is a polar molecule that can dissolve many solutes. H O H - ++ H O H - ++ Hydrogen Bonds Hydrogen Bonds: the (+) end of one water molecule attracts a (- ) end of another.

39. 38 Polar Molecules Def. – molecules with ‘charged’ regions due to the electronegativity of the elements Compare hydrogen and oxygen in the water molecule One side of a water molecule is slightly negative and the other is slightly positive.

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41. 40 Polar solvents dissolve polar solutes. Is oil polar???????? Why do you need soap to clean butter off a knife?

42. 41 “Like Dissolves Like” The charged ends of a polar solvent can separate the charged ends of a polar solute. Nonpolar molecules – have an equal sharing of electrons between atoms + - Is vinegar polar or non-polar? Is salt polar or non-polar?

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44. 43Ionization The formation of ions by solvent as it separates the solute particles in a solution  When you pour NaCl (salt) into water, ions are formed  Na + or Cl - Na + Cl - Na + Cl - Na + Cl - Na + Cl - Na + Cl - Na +

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46. 45Electrolytes A solution in which the solute has dissolved to create ions. These dissolved ions allow the solution to conduct electricity.

47. 46 Types of Electrolytes NONELECTROLYTE NONELECTROLYTE – formed by solutes that DO NOT dissociate into ions in solution STRONG ELECTROLYTE STRONG ELECTROLYTE – formed by solutes that COMPLETELY dissociate in solution WEAK ELECTROLYTE WEAK ELECTROLYTE – formed by solutes that DO NOT COMPLETELY dissociate in solution

48. 47 Why is it dangerous to use electric appliances around bathwater? Distilled Water is pure water with NO dissolved salts or minerals.

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