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Do Now. Define the following words: Solute Solvent Solution Provide an example of each. 1C. Investigating the Cause of the Fish Kill. Obtaining the knowledge & skills needed to evaluate Snake River water data & to determine the cause of the fish kill. 1C. Objectives.

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  1. Do Now Define the following words: Solute Solvent Solution Provide an example of each

  2. 1C. Investigating the Cause of the Fish Kill Obtaining the knowledge & skills needed to evaluate Snake River water data & to determine the cause of the fish kill

  3. 1C. Objectives • Explain the solubility of substances in water • Describe the behavior of ionic compounds, heavy metals, acids & bases, molecular substances, & gases (particularly oxygen) in water

  4. 1C.1 Solubility of Solids in Water

  5. What is solubility? • Imagine dissolving a spoonful of salt in water

  6. What is solubility? • The salt is the ____________ • The water is the ______________ • The mixture of the salt & the water is a __________________ • As you stir, the white crystals dissolve in the water • The solution is colorless & clear

  7. What is solubility? • What would happen if you added another spoonful of salt? • And another…. And another? • Eventually, you wouldn’t be able to dissolve any more. Some salt would fall to the bottom, no matter how long you stirred. • The solution would be saturated; it would hold all the solute it could.

  8. No more salt can dissolve.The solution is saturated.

  9. What is solubility? • If you heated the water, you might be able to dissolve a little more salt. • The maximum quantity of a substance that can dissolve in a certain quantity of water – at a specified temperature – is called its solubility. • You might say grams of salt per 100 grams of water at 20oC

  10. What is solubility? • Although size of the salt crystals & how vigorously you stir affect how long it would take for the salt to dissolve, they do not affect how much can dissolve at a specified temperature

  11. Temperature & Solubility • The amount of solute that can dissolve in a specified amount of solvent varies with temperature • The graphical representation of this relationship is called the solute’s solubility curve

  12. Temperature & Solubility • Each point on the solubility curve indicates a solution in which the solvent contains as much dissolved solute as it normally can at that temperature • Such a solution is called a saturated solution

  13. Temperature & Solubility • Question: At 40oC, how much KNO3 will dissolve in 100 g water to form a saturated solution? • Answer:

  14. Temperature & Solubility • Question: At 90oC, how much KCl will dissolve in 100 g water to form a saturated solution? • Answer:

  15. Temperature & Solubility • Question: At what temperature will 70 g of KNO3 dissolve in 100 g of water to make a saturated solution? • Answer:

  16. Temperature & Solubility • Question: Which one of the three solutes is the most affected by temperature? • Answer: • Question: The most affected? • Answer:

  17. Temperature & Solubility • Think about a solution that contains 80 g of KNO3 in 100 g of water at 60 oC • The point is below the curve • This is an unsaturated solution

  18. Temperature & Solubility • What do you expect would happen if you cooled a saturated solution? • Crystals would form and fall to the bottom – usually • Sometimes, cooling a saturated solution does not cause crystals to fall out • This is an unstable solution called a supersaturated solution

  19. Question • How much potassium nitrate will dissolve in 150g of water at 40°C? • Answer:

  20. Rock Candy When seed crystals are added to a supersaturated sugar solution, they cause excess dissolved sugar to crystallize onto a string

  21. Hot Springs As the water in Emerald Pool (Yellowstone National Park) cools and evaporates at the edges, it becomes supersaturated, and precipitates begin to form.

  22. Do Now Turn to page 76 and use the chart: What mass of O2 can be dissolved in 2000.0 g of water at 30.0 °C? Take out the worksheet and the homework (pg. 85 #1-5) from the other night.

  23. Objectives 1. SWBAT define Saturated, supersaturated, and unsaturated solutions. 2. SWBAT answer questions about solubility curves and practice reading and interpreting graphs.

  24. Stand Up and turn to the person next to you…Let’s Review the following words: Solute Solvent Solution Saturated Unsaturated Supersaturated

  25. Pg. 56 #1-3

  26. 1C.2 Solubility & Solubility Curves, pp. 55-56 As extra practice, you could read the sample problems & try the 3 questions at the bottom of p. 56. 1C.1 Supplement: Solubility & Solubility Curves

  27. Investigating Matter, pp. 57-59 1C.3 Constructing a Solubility Curve

  28. Do Now Explain why the crystals formed in the experiment yesterday.

  29. Objectives 1. SWBAT create a solubility curve based on their results 2. SWBAT describe two separate steps required in the dissolving process; 3. SWBAT explain how water’s polarity makes it an effective solvent for many ionic compounds.

  30. 1C.4 Dissolving Ionic Compounds

  31. Do Now Turn to page 75 and use the chart: What mass of O2 can be dissolved in 1500.0 g of water at 30.0 °C?

  32. Objectives 1. SWBAT define Saturated, supersaturated, and unsaturated solutions. 2. SWBAT answer questions about solubility curves and practice reading and interpreting graphs. 3. SWBAT describe two separate steps required in the dissolving process; 4. SWBAT explain how water’s polarity makes it an effective solvent for many ionic compounds.

  33. Dissolving Process • In your lab, you observed Potassium Nitrate dissolving in water • This is a macroscopic phenomenon • Chemistry is concerned with what happens at the particulate level – atomic and molecular phenomenon, which cannot be observed easily

  34. Dissolving Process • Factors that contribute to dissolving a solid material: • Temperature • Agitation • Time • But how do the particles of solute & solvent interact to make dissolving happen?

  35. Water’s Role • Water is a polar molecule • Although it is neutral overall, it has an uneven distribution of electrical charge. • Partial positive region at one end • Partial negative region at other end

  36. Water’s Role • It has a bent or V-shape • The Oxygen end has greater concentration of electrons than the two Hydrogen ends

  37. Water’s Role • View “Molecular Views of Water”

  38. Water’s Role • Polar water molecules are attracted to other polar substances & to substances composed of electrically charged particles • Electrical attractions make it possible for water to dissolve many kinds of substances

  39. Salt Dissolving in Water Think about the ions & molecules interacting at different times.

  40. Salt Dissolving in Water • Q. What forces hold the ionic lattice together? • A. Opposing ionic charges

  41. Salt Dissolving in Water • Q. Why do the water molecules interact with ions? • A. Water’s molecular polarity allows it to interact with both positive & negative ions.

  42. Salt Dissolving in Water • Q. What do the dissolved ions have in common with each other? • A. They are all solvated – surrounded – by water molecules.

  43. Salt Dissolving in Water • Q. How are the dissolved ions different? • A. Positive H ends of H2O are aligned with negative Cl ions, and negative O ends of H2O are aligned with positive Na ions

  44. Salt Dissolving in Water • Q. On the particulate level, what would evaporating water imply for this system? • A. The crystal lattice would begin to reform with fewer water molecules to overcome the ion-ion attractive forces.

  45. Water’s Role • View “Modeling Matter: Attraction Between Particles” • Q. What factors influence whether or not an ionic compound dissolves in water? • A. Properties of both solute & solvent, because dissolving involves competition among 3 types of attractions: • Solvent – Solute • Solvent – Solvent • Solute – Solute

  46. Water’s Role • View “Modeling Matter: Attraction Between Particles” • Q. What factors influence whether or not an ionic compound dissolves in water? • A. Properties of both solute & solvent, because dissolving involves competition among 3 types of attractions: • Solvent – Solute • Solvent – Solvent • Solute – Solute

  47. Think-Pair-Share Go to: http://www.sumanasinc.com/webcontent/animations/content/propertiesofwater/water.html And answer the following questions on the worksheet

  48. Do Now What ions does salt dissolve into? Draw each ion solvated by water molecules. (Make sure you draw the water molecules in the right direction!)

  49. Objectives 1. SWBAT practice reading and interpreting solubility curves. 2. SWBAT draw water molecules and orient them in the correct direction to dissolve various substances.

  50. Do Now • Draw a calcium ion solvated by water molecules.

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