1 / 31

Solutions

Brass = solution. Coffee = solution. Solutions. Chapter 15. Jayhawk says: Chemistry is awesome! Go KU!. The Triple “S” – solution, solvent, solute. Solution: a homogeneous mixture in which the components are uniformly intermingled.

enoch
Télécharger la présentation

Solutions

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Brass = solution Coffee = solution Solutions Chapter 15 Jayhawk says: Chemistry is awesome! Go KU!

  2. The Triple “S” – solution, solvent, solute • Solution: a homogeneous mixture in which the components are uniformly intermingled. • Solvent: the dissolving medium; substance present in the largest amount • Solute: substance dissolved in a solvent Jayhawk says: Did you know solutions with water as the solvent are Aqueous solutions? Solute + Solvent

  3. The Triple “S” – solution, solvent, solute • When a solid is being dissolved in a liquid to form a solution, three factors affect the speed of the dissolving process; Surface area, stirring and temperature. Jayhawk says: Did you know that the Jayhawks were the National Champions in basketball in 2008? Solute + Solvent

  4. Solubility • Solids • Gases

  5. The most commonly used expression of concentration is molarity. Molarity Jayhawksays: Rock Chalk Jayhawk!! Go KU!!

  6. M = moles of solute liter of solution Examples: #1) A solution contains 0.90 mol of NaCl in 0.50 L of water. Calculate the M of this solution. 0.90 mol NaCl = 1.8 M 0.50 L H2O Molarity Jayhawksays: Remember to convert to liters if given milliliters. #2) A solution contains 1.2 g of Magnesium chloride in 100 mL of Water. Calculate the M.

  7. Answer: 1.2g MgCl2 x 1 mol MgCl2 = 0.013mol MgCl2 93.2 g MgCl2 0.013 mol MgCl2= 0.13 M 0.100 L H2O Molarity Jayhawksays: Remember significant figure rules.

  8. Another Example!! A 0.40 M solution of glucose contains 8 moles of the solute. What is the volume of this solution? Molarity Jayhawksays: Chemistry RULES!!

  9. Answer: Molarity = mol solute L of soln So, L (volume) of soln = mol solute Molarity Molarity L = 8 mol 0.40 M Jayhawksays: Remember significant figure rules. Volume = 20 L

  10. Molality is the number of moles of a given substance per kilogram of solvent. • m = Moles of solute • Kg of Solvent • "one molal solution", i.e. a solution which contains one • mole of the solute per 1000 grams of the solvent. Molality Jayhawksays: Chemistry is my favorite class!!

  11. A solution is prepared by dissolving 0.500 mol of NaCl in 1.000 Kg of H20. Calculate the molality. A solution contains 1.5 mol of NaCl in 100. g of H20. Calculate the molality. Molality Jayhawksays: Who did the Jayhawks beat in the Orange Bowl last year?

  12. How many g of potassium iodide must be dissolved in 500. g of water to give a 0.060 molal solution? Molality Jayhawksays: You need to know molality so we can make ice cream.

  13. Mole Fraction • Ratio of the number of moles of solute to number of moles of solute and solvent (solution)

  14. To concentrate a solution, one must add more solute, or reduce the amount of solvent (for instance, by selective evaporation). • By contrast, to dilute a solution, one must add more solvent, or reduce the amount of solute. • The # of moles of solute stays constant. More H20 is added which increases the volume while decreasing the Molarity. Dilution Light, and able to see through, (lightly concentrated)

  15. Dilution Equation: • M(1)V(1) = M(2)V(2) • M(1)V(1) are the initial conditions • M(2)V(2) are the final conditions (dilute) Dilution

  16. How would you prepare 100 mL of 0.40 M MgSO4 from a stock solution of 2.0 M MgSO4? Dilution

  17. You have 1000 mL of 1.0 M HCl in your stockroom. You need 15 mL of 0.02 M solution for a lab. How much of the original solution will you need to make this solution? Dilution

  18. Dilution Equation: • M(1)V(1) = M(2)V(2) • M(1)V(1) are the initial conditions • M(2)V(2) are the final conditions (dilute) Dilution

  19. Definitions to Know • Saturated Solution • Unsaturated Solution • Supersaturated Solution Jayhawk says: I hope you learned something in this chapter, and remember, Rock Chalk Jayhawk!

  20. Percent Volume - volume of solute x 100 volume of soln - used for liquids dissolved within liquids Calculate the % V of isoprpopanol when 20. mL of the alcohol Is diluted with water for a final volume of 100. mL A soln has a total V of 1000 mL after water was added to 25 mL of ethanol. What is the % V of the ethanol soln? Jayhawk says: Listen up class, it’s time for an example.

  21. Mass Percent • mass of solute x 100 • mass of soln • grams of solution = grams of solute + grams of solvent A hydrochloric acid soln was made by adding 59.26 g of HCl to 100 g H20. Calculate the % mass of HCl in the soln. Calculate the mass % of octane when 10.5 g C8H18 is mixed with 40.0 g of C6H14.Octane is the solute. Jayhawk says: How many more days of school do we have? Answer on next page.

  22. Percent Mass/ Volume • mass of solute x 100 • volume of soln • most often seen with g/mL units, but g/L are o.k. (make sure to label) A 100 mL soln containing 7.0 g of MgCl2 is what % mass/volume of MgCl2? Jayhawk says: 45, After today!! Yippee!!

  23. Solution Composition • Calculating ion concentration from Molarity • Solute concentration is always written in terms of the solute form before it dissolves. • Now, we need to account for ions in soln, dissociation of ions when dissolved. Jayhawk says: What is in that beaker of magnesium chloride solution?

  24. Solution Composition • Needed • Solubility Tables • Balanced Equations • Net Ionic Equations • M = [ ] Jayhawk says: Don’t forget to always check your solubility table!

  25. Give the [ ] of all ions in the soln below • 0.50 M Co(NO3)2 • Dissociation Rxn: • Determine M of each ion:

  26. Give the [ ] of all ions in the soln below • 1.0 M FeCl3 • Dissociation Rxn: • Determine M of each ion:

  27. How many moles of Ag+ ions are present in 25 mL of a 0.75 M AgNO3 soln? • Unk: • Given: • Dissoc. Rxn:

  28. Solution Stoichiometry • Incorporating Stoichiometry, road maps, with new soln. info. • Use M, molarity: mol , L as a conversion factor between moles and Liters • L mol • Never use 22.4 L . This is for gases only!! • mol • Many types of problems . . . • Always start by writing a balanced equation • Make a road map • Write givens and unknown Jayhawk says: 22.4 L is for gases only!!

  29. Solution Stoichiometry 1.0 L of 0.120 M calcium nitrate reacts with 3.0 L 0.050 M sodium chromate. What mass of the precipitate will form? • Rxn: • Net Ionic: • Road Map: • Stoich: Jayhawk says: This is a limiting reactant problem. Remember those?!!

  30. Solution Stoichiometry What volume of 2.50 M soln of silver nitrate is needed to completely precipitate out 4.2 g of silver chloride? • Rxn: • Net Ionic: • Road Map: • Stoich: Jayhawk says: Don’t Forget, TEST Next Class!!

  31. Solution Stoichiometry Ammonium phosphate and calcium chloride react. 0.15 g of the ppt forms from excess (NH4)3PO4 and 416 mL of a CaCl2 soln. What must have been the [ ], in M of the CaCl2 soln? • Rxn: • Net Ionic: • Road Map: • Stoich: Jayhawk says: Study, Study, Study!!

More Related