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Happy New Year!! HMWK : Start Part 7 HP posted on Weebly – due 1/11

This homework assignment focuses on equilibrium shifts and acid-base reactions, including calculation of moles and concentrations. It also covers the naming of acids and bases.

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Happy New Year!! HMWK : Start Part 7 HP posted on Weebly – due 1/11

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  1. Happy New Year!! HMWK: Start Part 7 HP posted on Weebly– due 1/11 Warm-up… on loose leaf How many moles are in  3 L of a 1.2 M solution? 2. Given the equation 2SO2 + O2 → 2SO3: a. Which way will equilibrium shift if O2 is added? b. Which way will equilibrium shift if O2 is taken away? c. Write the equilibrium expression for the reaction.  (Note:  all are gases)  How many moles are in 45 g of LiCl? 4. If you take that amount of moles and dissolve it in 5 L of water, what is the concentration of the solution?

  2. ANSWERS How many moles are in  3 L of a 1.2 M solution? M = m 1.2 M = 0.4 moles L. 3 L. 2. Given the equation 2SO2 + O2 → 2SO3: Which way will equilibrium shift if O2 is added? To the right to use up what is added. b. Which way will equilibrium shift if O2 is taken away? To the left to replace what is lost c. Write the equilibrium expression for the reaction.  (Note:  all are gases) Keq = [SO3] 2 [ SO2]2 [O2]1  How many moles are in 45 g of LiCl? 45 g LiCl x 1 mole LiCl= 1.061 moles LiCl 42.391 g LiCl If you take that amount of moles and dissolve it in 5 L of water, what is the concentration of the solution? Molarity = M 1.016 M LiCl= 0.2032 M LiCL L 5L

  3. Acids and Bases Introduction • Get a note guide and NCFE exam review packet off the front table. • Sit in your assigned seat and put your phone away! • HMWK: • Part 7 HP posted to Weebly–due 1/11 • Work on last page of NCFE review packet on pH

  4. Acids • Sour taste • Examples: • HCl (stomach acid), H2SO4 • HC2H3O2 (acetic acid) – (vinegar = acetic acid & water) • Citric acid (lemon juice) • Electrolyte • Releases H+ when dissolved in water, producing hydronium ions! H+ + H2O  H3O+ • Hydronium ions are the hydrated form of H+

  5. Acids (cont’d) • React with metals to produce H2 gas. • Ex. HCl + Zn  ZnCl2 + H2 • When diluting acids, always slowly pour the acid into water while stirring. • Acid/Base Indicators: • Turns litmus paper RED. • Phenolphthalein does not change color.

  6. Bases • Bitter taste, slippery feel • Examples: NaOH, Mg(OH)2 (milk of magnesia), NH3 (ammonia), soap, household cleaners • Releases OH- (hydroxide ions) when dissolved in water. • Electrolyte. • Acid/Base Indicators: • Turns litmus paper BLUE. • Phenolphthalein turns bright pink.

  7. Neutralization Reaction • ACID + BASE  SALT + WATER • Salt: ionic compound formed from the negative part of the acid and the positive part of the base. • Example:   2HCl + Mg(OH)2MgCl2 + 2H2O • What type of reaction is this? Synthesis, Decomposition, Single Replacement, Double Replacement, or Combustion?

  8. Complete and Balance the Neutralization Reactions NaCl + H2O • HCl + NaOH • HC2H3O2 + Ca(OH)2 • HBr + Al(OH)3 2 2 Ca(C2H3O2)2 + H2O 3 3 AlBr3 + H2O

  9. Naming Acids • Acids are a group of ionic compounds with unique properties. • An acidis a compound that contains one or more hydrogen atoms and produces hydrogen ions (H+) when dissolved in water. • Chemical formula of an acid: HnX • X = monatomic anion or polyatomic anion • n = number of hydrogen atoms

  10. How to name an acid… • Depends on the name of the ANION 1. When the name of the anion (X) ends in –ide A. The acid name begins with the prefix hydro- B. The stem of the anion has a suffix –icfollowed by the word acid Example:HCl – (X = chloride) hydrochloric acid 2. When the name of the anion (X) ends in –ite A. The stem of the anion has a suffix –ous, followed by the word acid Example: H2SO3 – (X = sulfite) sulfurous acid 3. When the name of the anion (X) ends in –ate A. The stem of the anion has a suffix –ic, followed by the word acid Example: H3PO4 – (X = phosphate) phosphoric acid

  11. Naming Common Acids Textbook Table 9.5

  12. Practice: Hydrosulfuric acid • H2S • HNO2 • H2CO3 • HC2H3O2 • HF • H2O X = sulfide Nitrous acid X = nitrite Carbonic acid X = carbonate Acetic acid X = acetate X = fluoride Hydrofluoric acid Dihydrogen monoxide Water is NOT an Acid pH = 7 X = oxide

  13. More practice • Complete the neutralization reactions. • HNO3 + Ca(OH)2 • HCN + NaOH • H3PO4 + Ni(OH)2 • Name the following acids. • HI • H2SO3 • HClO4

  14. Naming Bases • A baseis an ionic compound that produces hydroxide ions when dissolved in water. • Bases are named in the same way as other ionic compounds • The name of the cation, followed by the name of the anion • Anion will always be hydroxide (OH1-) • Exception: NH3 - ammonia

  15. Practice: Lithium hydroxide • LiOH • Al(OH)3 • Fe(OH)3 • Mg(OH)2 • Pb(OH)2 • OH Aluminum hydroxide Iron (III) hydroxide Magnesium hydroxide Lead (II) hydroxide Hydroxide

  16. Thursday… 1-5-17 • Get out pH note packet from yesterday! • HMWK: • Work on pH page of NCFE packet. • HP part 7 due Wednesday… 1/11/17

  17. 3 Definitions of Acids & Bases 1) Arrhenius Theory • Acids: ionize to produce H+ ions in aqueous solution • Monoprotic: HNO3, HCl, HC2H3O2 • Diprotic: H2SO4, H2SO3 • Triprotic: H3PO4 • HNO3 NO3- + H+ • H2SO4  SO42- + 2H+

  18. Arrhenius Theory cont. • Bases: dissociate to produce OH- ions in aqueous solution • NaOH, KOH, Ca(OH)2, Al(OH)3 • NaOH Na+ + OH- • Ca(OH)2  Ca2+ + 2OH-

  19. Definitions (cont’d) 2) Brønsted-Lowry Theory • Hydrogen ion (H+) = a proton • Acids: proton donors – ex. HCl • Bases: proton acceptors – ex. NH3

  20. Conjugate Acids and Bases • A conjugate acid is the product that ACCEPTS the proton • A Conjugate base is the product that DONTATES the proton • Label: Acid, Base, Conjugate Base, Conjugate Acid • NH3 (aq) + H2O (l) NH4+ (aq) + OH- (aq) • HCl (g) + H2O (l) H3O+ (aq) + Cl- (aq) BASE ACID CA CB ACID BASE CA CB

  21. More Examples • Show the direction of H+ transfer. • Label: Acid, Base, Conjugate Base, Conjugate Acid • H2SO4 + OH- HSO41- + H2O • HSO41- + H2O SO42- + H3O+ ACID BASE CB CA ACID BASE CB CA

  22. Practice • For the following equations, label the acid, base, conjugate acid, and conjugate base. • Remember you are following the PROTON transfer. HNO2 + H2O  NO2- + H3O+ HCl + NH3  NH4+ + Cl-

  23. Definitions (cont’d) 3) Lewis Theory • Acids: electron-pair acceptor • Bases: electron-pair donor • HCl (g) + H2O (l) H3O+ (aq) + Cl- (aq) In the equation above, which compound is accepting the electron pair and which is donating? WORKSHEET on pH.. Due at the end of the period HCl ACCEPTS e- pair H2O DONATES e- pair

  24. Friday… 1-6-17 • Get out pH note packet… • HMWK: • Work on pH page of NCFE packet. • HP part 7 due Wednesday… 1/11/17 • Test on Solutions, Equilibrium and pH on Wed. 1/11/17

  25. pH Scale

  26. pH Scale • pH Scale: logarithmic scale in which [H+] is expressed as a number from 0 to 14.

  27. pH Scale AcidicNeutralBasic 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 COPY THIS ON YOUR PAPER!! [H+] 100 10-1 10-2 10-3 10-4 10-5 10-6 10-7 10-8 10-9 10-10 10-11 10-12 10-13 10-14 [OH-] 10-1410-13 10-12 10-11 10-10 10-9 10-8 10-7 10-6 10-5 10-4 10-3 10-2 10-1100

  28. pH – Examples (no calculator) • What is the pH if [HCl] = 1 x 10-4 M? • What is the [H+] if the pH = 9? • What is the pH if [NaOH] = 1 x 10-2 M • What is the concentration of [OH-] if the pOH is 3? 5)What is the concentration of [H+] if the pOH is 10? 4 1 x 10-9 12 1 x 10-3 1 x 10-4

  29. pH calculations – easy practice • What is the pH of the solution? • [H3O+] = 1 x 10-4 M • [H+] = 1 x 10-10 M • [HCl] = 1 x 10-2 M • What is the concentration of H3O+ if the pH is 5? • What is the concentration of H+ if the pH is 11?

  30. pH calculations – easy practice • What is the pH of the solution? • [H3O+] = 1 x 10-4 M 4 • [H+] = 1 x 10-10 M 10 • [HCl] = 1 x 10-2 M 2 • What is the concentration of H3O+ if the pH is 5? 1 x 10 -5 • What is the concentration of H+ if the pH is 11? 1 x 10 -11

  31. (cont’d) • What is the pOH of each solution? • [OH-] = 1 x 10-4 M • [NaOH] = 1 x 10-10 M • What is the pH of a solution if the pOH is 4? • What is the pH of each solution? • [OH-] = 1 x 10-8 M • [KOH] = 1 x 10-3 M • What is the [H3O+] in a solution if [OH-] = 1 x 10-3 M? • What is the [OH-] in a solution if [H3O+] = 1x 10-5 M?

  32. What is the pOH of each solution? • [OH-] = 1 x 10-4 M 4 • [NaOH] = 1 x 10-10 M 10 • What is the pH of a solution if the pOH is 4? 10 • What is the pH of each solution? • [OH-] = 1 x 10-8 M 6 • [KOH] = 1 x 10-3 M 11 • What is the [H3O+] in a solution if [OH-] = 1 x 10-3 M? 1 x 10 -11 8) What is the [OH-] in a solution if [H3O+] = 1x 10-5 M? 1 x 10-9

  33. pH equations • pH= - log [H+] • pOH = - log [OH-] • pH + pOH = 14 • [H+] x [OH-] = 1 x 10-14

  34. Practice – Using the equations Find the pH of the following solutions. Is the solution acidic or basic? • 0.01 M HCl • 0.050 M Ca(OH)2 • 2.6 x 10-12 M Mg(OH)2 • 1 x 10-7 M HC2H3O2 • Find the concentration of hydrogen ions if the pH is 3. • Find the concentration of hydroxide ions if the pH is 5.6. • Find the [H3O+] in a solution if [OH-] = 3 x 10-6 M

  35. 0.01 M HClpH= - log [0.01] = 2 Acid 0.050 M Ca(OH)2 pH= - log [ 0.05] pOH =1.3  pH =12.7 Base 2.6 x 10-12 M Mg(OH)2 pH= - log [ 2.6 x 10-12] pOH = 11.5 so pH = 2.5 Acid 1 x 10-7 M HC2H3O2pH = -log 1 x 10 -7 pH =7 Neutral Find the concentration of hydrogen ions if the pH is 3. 1 x 10 -3 Find the concentration of hydroxide ions if the pH is 5.6. pOH = 8.4 8.4 = -log [OH]- 4 x 10 -9 Find the [H3O+] in a solution if [OH-] = 3 x 10-6 M H+ + OH - = 3x 10 -6 M Solve for H+ x = 3.33 x 10 -9

  36. Welcome back!! • Let’s pick up where we left off… get out your pH notes from Friday and a calculator. Then pH lab….. HMWK: HP part 7 due and last test on ….

  37. Find the concentration of hydroxide ions if the pH is 5.6. pOH = 8.4 8.4 = -log [OH] divide by -1 on each side… gives you.. -8.4 = log [OH] there is no special base so this is log base ten which means…. [OH] = 10 -8.4 4 x 10 -9 Find the [H+] in a solution if [OH-] = 3 x 10-6 M [H+] x [OH-]= 1 x 10 -14 Solve for [H+] [H+] x [3x10-6] = 1 x 10 -14 [3x10-6] [3x10-6] [H+] = 3.33 x 10 -9

  38. Strong Acids and Bases • Strong Acids: completely ionize in water • Ex. HCl, HBr, HI, HNO3, H2SO4, HClO3 • Strong Bases: completely dissociate into ions in water • Ex. NaOH, LiOH, KOH, Ca(OH)2, Sr(OH)2, Ba(OH)2

  39. Weak Acids and Bases • Weak Acids: only some molecules ionize in water • Ex: acetic acid (less than 0.5% of molecules ionize) • Weak Bases: do not completely dissociate into ions in water • Ex: ammonia (only 0.5% of molecules dissociate)

  40. Concentrated vs. Strong • “Concentrated” – refers to the amount dissolved in solution. • “Strong” – refers to the fraction of molecules that ionize.   • For example, if you put a lot of ammonia into a little water, you will create a highly concentrated solution. However, since only 0.5% of ammonia molecules ionize in water, this basic solution will not be very strong.

  41. Acid-Base Titration • Uses a neutralization reaction to determine the concentration of an acid or base. • Standard Solution: the reactant that has a known molarity • Endpoint: the point at which the unknown has been neutralized.

  42. Titration Examples • Example #1) .08 L of 0.100MNaOH is used to neutralize .02 L of HCl. What is the molarity of HCl?NaOH + HClNaCl + H2O .08 L NaOH x .100 molsNaOHx 1 molHClx 1 = 1 L NaOH 1 molNaOH 0.02 L HCl 0.4 M Molarity of NaOH Molar Ratio Make sure you finish with correct units!!

  43. Titration Examples (cont’d) • Example #2) A 0.1M Mg(OH)2 solution was used to titrate an HBr solution of unknown concentration. At the endpoint, 21.0 mL of Mg(OH)2 solution had neutralized 10.0 mL of HBr. What is the molarity of the HBr solution? • MAVA = MBVB • 0.1 x 21 ml = ? X 10 ml • X = 0.21 M HBr

  44. Titration examples can be done with…. M1V1 = M2 V2 • Or MAVA = MBVB

  45. Titration Practice • What is the molarity of an Al(OH)3 solution if 30.0 mL of the solution is neutralized by 26.4 mL of a 0.25 M HBr solution? 30 ml x M = 26.4 x 0.25 .22M Al 9(OH3) 2) A 0.3 Ca(OH)2 solution was used to titrate an HCl solution of unknown concentration. At the endpoint, 35.0 mL of Ca(OH)2 solution had neutralized 10.0 mL of HCl. What is the molarity of the HCl solution? .3M x 35ml = 10ml x M M = 10.5 HCl 3) When 34.2 mL of a 1.02 M NaOH solution is added from a buret to 25.00 mL of a phosphoric acid solution that contains phenolphthalein, the solution changes from colorless to pink.  What is the molarity of the phosphoric acid?34.2ml x 1.02 M = 25 ml x M M = 1.4 M HPO4

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