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Don't Delay, Work Today - Deadline May 26th @ 8:00am

Urgent reminder with 22 days left to complete your tasks. Includes Roman numerals, gas law problems, acids and bases, pH scale explanations, and titration concepts.

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Don't Delay, Work Today - Deadline May 26th @ 8:00am

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  1. Time is Running out – Late/Missing or work being redone is due no later than May 26th @ 8:00am So don’t simply keep your head in the sand, get your work done!! Only 22 days remaining

  2. Bellringer List the Roman Numerals from 1 to 10

  3. Bellringer Mixed Gas Law Practice Problems Dry ice is carbon dioxide in the solid state. 1.28 grams of dry ice is placed in a 5.00 L chamber that is maintained at 35.1oC. What is the pressure in the chamber after all of the dry ice has sublimed? Assume R of 0.0821 L*atm/mole*K

  4. 0.0290249 Moles CO2 0.147 Atm

  5. Acids and Bases

  6. ACIDS Taste sour Turn litmus React with active metals – Fe, Zn React with bases BASES Taste bitter Turn litmus Feel soapy or slippery (react with fats to make soap) React with acids General properties blue to red red to blue

  7. Definitions • Acids – produce H+ • Bases - produce OH- • Acids – donate H+ • Bases – accept H+ • Acids – accept e- pair • Bases – donate e- pair Arrehenius only in water Bronsted-Lowry any solvent Lewis used in organic chemistry, wider range of substances

  8. Neutralization In general: Acid + Base  Salt + Water All neutralization reactions are double displacement reactions. HCl + NaOH  NaCl + HOH HCl + Mg(OH)2 H2SO4 + NaHCO3

  9. Does pure water conduct electrical current? Water is a very, very, very weak electrolyte. H2O  H+ + OH- How are (H+) and (OH-) related? (H+)(OH-) = 10-14 For pure water: (H+) = (OH-) = 10-7M This is neutrality and at 25oC is a pH = 7. water

  10. Let’s examine the behavior of an acid, HA, in aqueous solution. HA What happens to the HA molecules in solution?

  11. 100% dissociation of HA HA H+ Strong Acid A- Would the solution be conductive?

  12. Partial dissociation of HA HA H+ Weak Acid A- Would the solution be conductive?

  13. HA  H+ + A- HA H+ Weak Acid A- At any one time, only a fraction of the molecules are dissociated.

  14. Strong and Weak Acids/Bases Strong acids/bases – 100% dissociation into ions HCl NaOH HNO3KOH H2SO4 Weak acids/bases – partial dissociation, both ions and molecules CH3COOHNH3

  15. acid rain (NOx, SOx) pH of 4.2 - 4.4 in Washington DC area pH 0-14 scale for the chemists 2 3 4 5 6 7 8 9 10 11 12 acidic (H+) > (OH-) neutral @ 25oC (H+) = (OH-) distilled water basic or alkaline (H+) < (OH-) normal rain (CO2) pH = 5.3 – 5.7 fish populations drop off pH < 6 and to zero pH < 5 natural waters pH = 6.5 - 8.5

  16. 105 Db 107 Bh Behavior of oxides in water– Group A basic amphoteric acidic 8A 1A 3A 4A 5A 6A 7A 2A Group B basic: Na2O + H2O  2NaOH (O-2 + H2O  2OH-) acidic: CO2 + H2O  H2CO3

  17. B. pH Scale pH of Common Substances

  18. pH The biological view in the human body acidic basic/alkaline 1 2 3 4 5 6 7 8 9 10 11 blood saliva urine gastric juice pancreatic juice bile cerebrospinal fluid Tortora & Grabowski, Prin. of Anatomy & Physiology, 10th ed., Wiley (2003)

  19. Time is Running out – Work due no later than May 26th @ 8:00am Only 17 days remaining

  20. Dilution water (solvent) solute moles of solute remain constant diluted, Mfinal Vfinal molesinitial = molesfinal Vinitial concentrated, Minitial adding water lowers the solute concentration Mfinal x Vfinal = Minitial x Vinitial

  21. Titration Calculation indicator HCl + NaOH  NaCl + HOH A way to analyze solutions! at equivalence point: moleHCl = moleNaOH moles = M x VL Macid x Vinitial acid = Mbase x Vburet

  22. pouvoir hydrogène (Fr.) “hydrogen power” B. pH Scale 14 0 NEUTRAL 7 INCREASING BASICITY INCREASING ACIDITY pH = -log[H3O+]

  23. B. pH Scale pH = -log[H3O+] pOH = -log[OH-] pH + pOH = 14

  24. B. pH Scale • What is the pH of 0.050 M HNO3? pH = -log[H3O+] pH = -log[0.050] pH = 1.3 Acidic or basic? Acidic

  25. B. pH Scale • In household bleach, the concentration of OH- ions is 5.0 x 10-2 M. What is the pH? pOH = -log[OH-] pOH = -log[5.0 x 10-2] pOH = 1.3 pH + pOH = 14 pH + 1.3 = 14 pH = 12.7 BASIC

  26. III. Titration Ch. 19 - Acids & Bases

  27. A. Neutralization • Chemical reaction between an acid and a base. • Products are a salt (ionic compound) and water.

  28. A. Neutralization ACID + BASE  SALT + WATER HCl + NaOH  NaCl + H2O strong strong neutral HC2H3O2 + NaOH  NaC2H3O2 + H2O weak strong basic • Salts can be neutral, acidic, or basic. • Neutralization does not mean pH = 7.

  29. standard solution unknown solution B. Titration • Titration • Analytical method in which a standard solution is used to determine the concentration of an unknown solution. (neutralization rxn.)

  30. B. Titration • Equivalence point (endpoint) • Point at which equal amounts of H3O+ and OH- have been added. • Determined by… • indicator color change • dramatic change in pH

  31. B. Titration moles H3O+ = moles OH- MVn = MVn M: Molarity V: volume n: # of H+ ions in the acid or OH- ions in the base

  32. B. Titration • 42.5 mL of 1.3M KOH are required to neutralize 50.0 mL of H2SO4. Find the molarity of H2SO4. H3O+ M = ? V = 50.0 mL n = 2 OH- M = 1.3M V = 42.5 mL n = 1 MV# = MV# M(50.0mL)(2) =(1.3M)(42.5mL)(1) M = 0.55M H2SO4

  33. H H – + N O O N H H H H H H H H Definition • Arrhenius - In aqueous solution… • Bases form hydroxide ions (OH-) NH3+ H2O  NH4+ + OH- base

  34. Bronsted-Lowry Definitions • An acid is a proton (H+) donor and a base is a proton acceptor. • Acids and bases always come in pairs. • HCl is an acid. • When it dissolves in water it gives its proton to water. • HCl(g) + H2O(l) H3O+ + Cl- • Water is a base makes hydronium ion.

  35. conjugate base conjugate acid Bronsted-Lowry Definitions • Brønsted-Lowry • Acidsare proton (H+) donors. • Bases are proton (H+) acceptors. HCl + H2O  Cl– + H3O+ acid base

  36. F - H2PO4- H2O HF H3PO4 H3O+ Bronsted-Lowry Definitions • Give the conjugate base for each of the following: • Polyprotic - an acid with more than one H+

  37. Br - HSO4- CO32- HBr H2SO4 HCO3- Bronsted-Lowry Definitions • Give the conjugate acid for each of the following:

  38. Come in Pairs • General equation • HA(aq) + H2O(l) H3O+(aq) + A-(aq) • Acid + Base Conjugate acid + Conjugate base • This is an equilibrium. • B(aq) + H2O(l) BH+(aq) + OH-(aq) • Base + Acid Conjugate acid + Conjugate base • NH3(aq)+H2O(l) NH4+(aq)+OH-(aq)

  39. Normal Assignment • Term review Page 580 1-12

  40. Mondo Assignment • Term review Page 580 1-12 • Concept Review Page 580-581 1-16, 17-19 • Linking Chapters Page 584 1-5

  41. Mega Assignment • Term review Page 580 1-12 • Concept Review Page 580-583 1-16, 17-19, 31-39, 41-44 • Linking Chapters Page 584 1-5

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