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Solution Chemistry

Solution Chemistry. Solutions, Problems, Solutions, Problems. Does it ever end?. How can you express concentration?. How can you express concentration?. Mass % composition Molarity Molality Mole fraction Density. Mass % problems:. Find mass % Find amount of solute

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Solution Chemistry

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  1. Solution Chemistry Solutions, Problems, Solutions, Problems. Does it ever end?

  2. How can you express concentration?

  3. How can you express concentration? • Mass % composition • Molarity • Molality • Mole fraction • Density

  4. Mass % problems: • Find mass % • Find amount of solute • Find total mass of solution

  5. Mass % problems: • Find mass % • Mass % = mass of solute x 100 % total mass of solution Don’t forget to add the masses of the solute and solvent for the total mass

  6. Mass % problems: • Find amount of solute • Mass % = mass of solute x 100 % total mass of solution • Multiply by total mass and divide by 100% to solve for mass of solute

  7. Mass % problems: • Find total mass of solution • Mass % = mass of solute x 100 % total mass of solution • Multiply both sides by the mass of solution first to get it out of the denominator.

  8. Molarity problems: • Find molarity • Find amount of solute • Find volume of solution

  9. Molarity problems: • Find molarity • M= moles solute Volume of solution (L)

  10. Molarity problems: • Find amount of solute • M= moles solute Volume of solution (L) • Molarity x volume= moles!

  11. Molarity problems: • Find volume of solution • M= moles solute Volume of solution (L) • Multiply both sides by the volume of solution first to get it out of the denominator. OR!

  12. Molarity problems: • Find volume of solution • Use the molarity as a conversion factor! • moles solute x 1 L = Volume of solution! M

  13. Dilution Problems M x V = Moles • Moles of solute in new solution = moles in the stock solution. Molarity goes down, volume goes up

  14. Dilution Problems Example: What is the concentration of a solution made by diluting 25 ml of a .50 M HCl solution to a new volume of 150 ml?

  15. Dilution Problems Example: What is the concentration of a solution made by diluting 25 ml of a .50 M HCl solution to a new volume of 150 ml? M x V = moles. .50 M x .025 L= .0125 moles HCl M = mol/vol= .0125 mol / .150 L = .083 M

  16. Dilution Problems • What is the concentration of a solution made by diluting 125 ml of a 2.5 M NH3solution to a new volume of 350 ml? • What is the concentration of a solution made by diluting 2.5 ml of a 6.0 M NaClsolution to a new volume of 80. ml? • What is the concentration of a solution made by diluting 30. ml of a 1.0 M Fe(NO3)3solution with 20. ml of water? (The final volume should be 20. + 30. = 50. ml)

  17. Dilution Problems Example: What volume of a 2.0 M NaOH stock solution is required to mix 1.50 L of a .150 M NaOH solution?

  18. Dilution Problems Example: What volume of a 2.0 M NaOH stock solution is required to mix 1.50 L of a .150 M NaOH solution? M x V = moles. .150 M x 1.50 L = .225 moles NaOH .225 moles NaOH x 1 L/ 2.0 moles= .113 L

  19. Dilution Problems • What volume of a 6.0 M NaOH stock solution is required to mix 1.50 L of a .150 M NaOH solution? • What volume of a 2.0 M MgCl2stock solution is required to mix 1.750 L of a .10 M MgCl2solution? • What volume of a 1.0 M HClstock solution is required to mix 100. ml of a .10 M HCl solution?

  20. Volume Stoichiometry • If you mix 10. ml of .10 M HCl with .10 M NaOH, • …it should take 10. ml of the NaOH to react completely.

  21. Volume Stoichiometry • If you mix 10. ml of .10 M HCl with .20 M NaOH, • …it should take only 5.0 ml of the NaOH to react completely.

  22. Volume Problems • If you react 10.0 ml of .10 M HCl with .050 M NaOH, what volume of NaOH solution will be needed? • If you react 10.0 ml of .10 M H2SO4with .050 M NaOH, what volume of NaOH solution will be needed? • If you react 50.0 ml of 1.0 M CaCl2with 1.9 M Na2CO3, what volume of Na2CO3solution will be needed?

  23. Volume Stoichiometry • If 10. ml of .10 M HCl reacts completely with 10. ml NaOH, • …the concentration of the NaOH must be the same, .10 M

  24. Volume Stoichiometry • If 10. ml of .10 M HCl reacts completely with 20. ml NaOH, • …the concentration of the NaOH must be half of that, .050 M.

  25. Volume problems • If 25.0 ml of .30 M HCl reacts completely with 25. ml NaOH, what is the concentration of the NaOH? • If 10.0 ml of .10 M HCl reacts completely with 20. ml NaOH, what is the concentration of the NaOH? • If 15.0 ml of .10 M HCl reacts completely with 50. ml Pb(NO3)2, what is the concentration of the Pb(NO3)2?

  26. Acids and Bases

  27. Acids Bases Examples?

  28. Acids Bases Properties of Acids and Bases

  29. Acids Are electrolyte solutions Make ions in solution Affect indicators Have low pH Taste sour Neutralize bases Can cause serious burns Corrode reactive metals Have more H+ than OH- (in solution) Bases Are electrolyte solutions Make ions in solution Affect indicators Have high pH Taste bitter Neutralize acids Can cause serious burns Corrode aluminum only Have more OH- than H+ (in solution) Properties of Acids and Bases

  30. Acids Are electrolyte solutions Make ions in solution Affect indicators Have low pH Taste sour Neutralize bases Can cause serious burns Corrode reactive metals Have more H+ than OH- (in solution) Bases Are electrolyte solutions Make ions in solution Affect indicators Have high pH Taste bitter Neutralize acids Can cause serious burns Corrode aluminum only Have more OH- than H+ (in solution) Properties of Both

  31. BrØnsted-Lowry Definition • Substances that donate a proton (H+ ion) in a reaction are acids. • Substances that accept a proton (H+ ion) are bases. • Arrhenius acids and bases make H+ and OH- ions in solution. BrØnsted-Lowry bases are also Arrhenius bases.

  32. pH • The basic (and acidic) definitions are: pH= -log [H+] [H+]= 10-pH pOH= -log [OH-] [OH-]=10 -pOH Kw=[H+][OH-]=1 x 10 -14 (at 25oC) pH + pOH = 14 (at 25oC)

  33. pH practice • If pH is 3.38…. • What is the pOH?

  34. pH practice • If pH is 3.38…. • What is the pOH? 14-pH= 10.62

  35. pH practice • If pH is 3.38…. • What is the pOH? 14-pH= 10.62 • What is [H+]?

  36. pH practice • If pH is 3.38…. • What is the pOH? 14-pH= 10.62 • What is [H+]? 10-3.38= 4.17 x 10-4M

  37. pH practice • If pH is 3.38…. • What is the pOH? 14-pH= 10.62 • What is [H+]? 10-3.38= 4.17 x 10-4M • What is [OH-]?

  38. pH practice • If pH is 3.38…. • What is the pOH? 14-pH= 10.62 • What is [H+]? 10-3.38= 4.17 x 10-4M • What is [OH-]? 10-10.62=2.40x10-11M and Kw/4.17x10-4M=2.40x10-11 M!

  39. pH practice • If [OH-]= 4.8 x 10-6 M…

  40. pH practice • If [OH-]= 4.8 x 10-6 M… • What is pOH?

  41. pH practice • If [OH-]= 4.8 x 10-6 M… • What is pOH? -log (4.8 x 10-6 )= 5.32

  42. pH practice • If [OH-]= 4.8 x 10-6 M… • What is pOH? -log (4.8 x 10-6 )= 5.32 • What is pH?

  43. pH practice • If [OH-]= 4.8 x 10-6 M… • What is pOH? -log (4.8 x 10-6 )= 5.32 • What is pH? 14-5.32= 8.68

  44. pH practice • If [OH-]= 4.8 x 10-6 M… • What is pOH? -log (4.8 x 10-6 )= 5.32 • What is pH? 14-5.32= 8.68 • What is [H+]?

  45. pH practice • If [OH-]= 4.8 x 10-6 M… • What is pOH? -log (4.8 x 10-6 )= 5.32 • What is pH? 14-5.32= 8.68 • What is [H+]? 10-8.68= 2.08 x 10-9 M and Kw/ 4.8 x 10-6 = 2.08 x 10-9 M !

  46. Please recall: • Strongacids and bases dissociate completely in water. Weak acids/bases do not. • Strong acids= nitric, hydrochloric, sulfuric, hydrobromic, hydroiodic, perchloric • Strong bases-Group 1 & 2 hydroxides—(group 2’s don’t dissolve much)

  47. Please recall: • What is the concentration (M) of NaOH if .35 mole NaOH is dissolved in .120 L solution? • What is the molarity of HCl if 12 g HCl is dissolved in .85 L of solution? • What is [OH-] if .35 g Ba(OH)2 is dissolved in .250 L solution? • What mass of H2SO4 is in 55 ml of .38 M H2SO4?

  48. Please recall: • What is the concentration (M) of NaOH if .35 moleNaOH is dissolved in .120 L solution? • What is the molarity of HCl if 12 gHCl is dissolved in .85 L of solution? • What is [OH-] if .35 g Ba(OH)2 is dissolved in .250 L solution? • What mass of H2SO4 is in 55 ml of .38 M H2SO4? Did you notice?

  49. Analyze these solutions

  50. Right!

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