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Acids, Bases and Salts HW Vocabulary pH and pOH Calculation pH Practice Problems Ch 20 Practice Problems (13 questions) Aspirin Article Aqueous Acid Base – Titration Lab - Neutralization

HCl H 2 SO 4 H 3 PO 4 HNO 3 CH 3 COOH HF Hydrochloric acid Sulfuric acid Phosphoric acid Nitric acid Acetic acid Hydrofluoric acid stomach acid, pickling metal battery acid, # 1 selling chemical food flavoring fertilizer, explosives vinegar etch glass NaOH Ca(OH) 2 NH 4 OH sodium hydroxide calcium hydroxideammonium hydroxide

pH scale acid neutral base [H + ] = [OH - ] Soren Sorenson developed pH scale pOH = -log [OH - ] k W = [H + ] [OH - ] pH = -log [H + ] pH + pOH = 14 (alkalinity) Arnold Beckman invented the pH meter H + + H 2 O H 3 O + protonhydronium ion k w = 1 x

Concentrated vs. Dilute Concentration: Molarity molality Normality M = mol L m = mol kg H 2 SO 4 2 H 1+ + SO M “6 M”

Strong / Weak Acid Strong HA H + + A - (~100% dissociation) Weak HA H + + A - (~20% dissociation) K a = [Product] [Reactant] acid dissociation constant KaKa 0.8 H 3 PO 4 3H + + PO HF H + + F - H 2 A 2 H + + A - K a = [H + ] 2 [A - ] [H 2 A]

Acid + Base Salt + Water How would you make calcium sulfate in the lab? + CaSO 4 ACID Sour taste, litmus red Arrhenius – H + as only ion in water Brønsted-Lowry – proton donor BASE bitter taste, litmus blue Arrhenius – OH - as only ion in water Brønsted-Lowry – proton acceptor H 2 SO 4 Ca(OH) H 2 O ??

phenolphthalein colorless pink acid baseweak strong bromthymol blue yellow blue acid basestrong universal indicator R O Y G B I V pH litmus paper & pH paper Indicators

Buffers - salts of weak acids and weak bases that maintain a pH LeChatelier’s Principle - acidosis & alkalosis (bicarbonate ion acts as buffer) - darkening glasses - egg shells thinner in summer (warm) e.g. Aspirin (acetyl salicylic acid) vs. Bufferin low pH upsets stomach

Video - Future of the Past KeysKeys Video: The Future of the Past

Acid – Base Concentrations pH = 3 pH = 7 pH = 11 OH - H3O+H3O+ H3O+H3O+ H3O+H3O+ [H 3 O + ] = [OH - ] [H 3 O + ] > [OH - ] [H 3 O + ] < [OH - ] acidic solution neutral solution basic solution concentration (moles/L) Timberlake, Chemistry 7 th Edition, page 332

Amino Acids – Functional Groups AmineCarboxylic AcidBase Pair NH 2 1- R- COOH NH 3 NH 2 1- NH 4 1+ amineammoniaammonium ion N H H H : N H H H H : 1+ N H H : 1- : H+H+ lose H +

Amino Acids – Functional Groups AmineCarboxylic AcidBase Pair NH 2 1- R- COOH O 2- H+H+ H+H+  ++

Water – Amphiprotic H2OH2OOH 1- H 3 O 1+ hydroxidewaterhydronium ion N H H H : N H H H H : 1+ N H H : 1- : H+H+ lose H +

Water – Also Amphiprotic H2OH2OOH 1- H 3 O 1+ hydroxidewaterhydronium ion H+H+ lose H + Amphiprotic – Act as an acid (proton donor) or base (proton acceptor) O 2- H+H+ H+H+  ++

Amino Acids – Functional Groups H2OH2OOH 1- H 3 O 1+ hydroxidewaterhydronium ion H+H+ lose H + Amphiprotic – Act as an acid (proton donor) or base (proton acceptor) O 2- H+H+ H+H+  ++

Range and Color Changes of Some Common Acid-Base Indicators Indicators pH Scale Methyl orange red 3.1 – 4.4 yellow Methyl red red yellow Bromthymol blue yellow blue Neutral red red yellow Phenolphthalein colorless red colorless beyond 13.0

Range and Color Changes of Some Common Acid-Base Indicators Indicators pH Scale Methyl orange red 3.1 – 4.4 yellow Methyl red red yellow Bromthymol blue yellow blue Neutral red red yellow Phenolphthalein colorless red colorless beyond 13.0

pH Paper pH pH pH Paper pH pH pH Paper pH pH pH Paper pH pH

Amphoteric

Neutralization of Bug Bites Wasp - stings with base (neutralize with lemon juice or vinegar) Red Ant - bites with acid (neutralize with baking soda)

Strength  Strong Acid/Base 100% ionized in water strong electrolyte - + HCl HNO 3 H 2 SO 4 HBr HI HClO 4 NaOH KOH Ca(OH) 2 Ba(OH) 2 Courtesy Christy Johannesson

Strength  Weak Acid/Base does not ionize completely weak electrolyte - + HF CH 3 COOH H 3 PO 4 H 2 CO 3 HCN NH 3 Courtesy Christy Johannesson

Ionization of Water H 2 O + H 2 O H 3 O + + OH - K w = [H 3 O + ][OH - ] = 1.0  Courtesy Christy Johannesson

Why is pure water pH = 7? 11 in 500,000,000 water molecules will autoionize. HH 2 O + H 2 O  H 3 O + + OH 1- TThis yields a hydronium ion concentration of 1 x M H 3 O + per liter of solution ppH = -log[H 3 O + ] ppH = -log[1 x ] or pH = 7

H H O H H H H H H O H H H H O H H H H O H H H H O H H H H O H H O H H H H H H O H H

Ionization of Water  Find the hydroxide ion concentration of 3.0  M HCl. [H 3 O + ][OH - ] = 1.0  [3.0  ][OH - ] = 1.0  [OH - ] = 3.3  M Acidic or basic? Acidic Courtesy Christy Johannesson

pH = -log[H 3 O + ] pH Scale 0 7 INCREASING ACIDITY NEUTRAL INCREASING BASICITY 14 pouvoir hydrogène (Fr.) “hydrogen power” Courtesy Christy Johannesson

pH Scale pH = -log[H 3 O + ] pOH = -log[OH - ] pH + pOH = 14 Courtesy Christy Johannesson

pH Scale  What is the pH of M HNO 3 ? pH = -log[H 3 O + ] pH = -log[0.050] pH = 1.3 Acidic or basic? Acidic Courtesy Christy Johannesson

pH Scale  What is the molarity of HBr in a solution that has a pOH of 9.6? pH + pOH = 14 pH = 14 pH = 4.4 Acidic pH = -log[H 3 O + ] 4.4 = -log[H 3 O + ] -4.4 = log[H 3 O + ] [H 3 O + ] = 4.0  M HBr Courtesy Christy Johannesson

Resources - Acids and Bases Objectives WorksheetWorksheet - vocabulary vocabulary Worksheetvocabulary WorksheetWorksheet - pH and pOH calculations pH and pOH calculations WorksheetpH and pOH calculations WorksheetWorksheet - practice problems (key) key Worksheetkey TextbookTextbook - text ?'s chemical equilibrium Textbook Worksheet - weak acid, pK a Article - aspirin LabLab - synthesis of aspirin Lab WorksheetWorksheet - aqueous acids and bases titration Worksheet (general) Outline (general) Outline VideoVideo (VHS) - future of the past Video Outline - Worksheet - Lab - titration TextbookTextbook - questions questions Textbookquestions

Resources - Acids and Bases Objectives WorksheetWorksheet - vocabulary Worksheet Worksheet - pH and pOH calculations Worksheet Worksheet - practice problems (key) Worksheet TextbookTextbook - text ?'s chemical equilibrium Textbook Worksheet - weak acid, pK a Article - aspirin LabLab - synthesis of aspirin synthesis of aspirin Labsynthesis of aspirin WorksheetWorksheet - aqueous acids and bases titration Worksheet (general) Outline (general)general Outlinegeneral VideoVideo (VHS) - future of the past Video Outline - Worksheet - LabLab - titration Lab TextbookTextbook - questions Textbook Episode 16Episode 16 – The Proton in Chemistry