19.1 Acid-Base Theories> 1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Day The pH for a 0.10 M solution of a monoprotic acid is 1.2, what is the K a ? 0.108

19.1 Acid-Base Theories> 2 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. page 669 #s  due Tuesday Day Day

19.1 Acid-Base Theories> 3 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. III. Strong and Weak Acids and Bases Base Dissociation Constant – K b Write the K eq for the dissociation of NH 3(aq) above. *** for dilute aqueous solutions the concentration of water is a constant so, K eq = [NH 4 + ] * [OH - ] [NH 3 ] * [H 2 O]

19.1 Acid-Base Theories> 4 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. III. Strong and Weak Acids and Bases Base Dissociation Constant – K b Or in general form:  the base dissociation constant (K b ) measures the extent to which a base dissociates in aqueous solution, and so can be used to represent the strength of a base. The stronger the base, the higher the K b value. K b = [conjugate acid] * [OH - ] [base]

19.1 Acid-Base Theories> 5 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. III. Strong and Weak Acids and Bases Differentiating Concentration and Strength: Strength refers to the extent of ionization or dissociation of an acid or base, while concentration indicates how much of a substance is dissolved.  Recall that substances can dissolve without dissociating (sugar).

19.1 Acid-Base Theories> 6 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. III. Strong and Weak Acids and Bases Differentiating Concentration and Strength: *** Strength is independent of concentration and vice versa. Acidic Solution Molar Concentration Relative Concentration Relative Strength Hydrochloric acid 12 M HClConcentratedStrong Gastric Juice (stomach acid) 0.08 M HClDiluteStrong Acetic acid17 M CH 3 COOHConcentratedWeak Vinegar0.2 M CH 3 COOHDiluteWeak

19.1 Acid-Base Theories> 7 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. IV. Neutralization Reactions Acid-Base Reactions = Neutralization Reactions  In general acids and bases react to produce a salt (ionic substance) and water.  The complete reaction of a strong acid and a strong base produces a neutral solution – neutralization reaction. Example: HCl (aq) + NaOH (aq)  NaCl (aq) + H 2 O (l)

19.1 Acid-Base Theories> 8 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. IV. Neutralization Reactions Acid-Base Reactions = Neutralization Reactions  Mole Ratios and Neutralization Reactions (example problem) How many moles of sulfuric acid are needed to neutralize 0.50 moles of sodium hydroxide?

19.1 Acid-Base Theories> 9 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Day Get out your sign-off sheet for the final project.

19.1 Acid-Base Theories> 10 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. 1.HNO 3 is a strong acid – assume it completely dissociates in water. Calculate the pH of each of a solution containing 1.02 g of HNO 3 in 250. mL of solution. Day

19.1 Acid-Base Theories> 11 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Day How many moles of nitric acid are needed to neutralize 0.50 moles of calcium hydroxide? 2HNO 3 + Ca(OH) 2  Ca(NO 3 ) 2 + 2H 2 O 1 mole

19.1 Acid-Base Theories> 12 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. m/esm_brown_chemist ry_9/2/660/ cw/i ndex.html Homework # 1 Chapter 16 – show me successful screen (100%) OR to me – due Tues Day

19.1 Acid-Base Theories> 13 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Titration Titration = the process of adding a measured amount of a solution of known concentration to a solution of unknown concentration – using a neutralization reaction to determine concentration Steps: 1. a measured volume of an acid solution of unknown concentration is added to a flask 2. an indicator is added 3. measured volumes of a base of known concentration are mixed into the acid until the indicator just barely changes color

19.1 Acid-Base Theories> 14 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Titration  The solution of known concentration is called the standard solution.  Neutralization occurs (titration is complete) when the number of hydrogen ions equals the number of hydroxide ions. = the equivalence point = end point

19.1 Acid-Base Theories> 15 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Titration  Determining the concentration by titration mathematically: Example: A 25 mL solution of H 2 SO 4 is neutralized by 18 mL of 1.0 M NaOH. What is the concentration of the H 2 SO 4 solution? The equation for the reaction is: H 2 SO 4(aq) + 2NaOH (aq)  Na 2 SO 4(aq) + 2H 2 O (l) Conversion plan: you need mols H 2 SO 4 to calculate molarity L NaOH  mols NaOH  mols H 2 SO 4

19.1 Acid-Base Theories> 16 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Titration  Determining the concentration by titration mathematically: Additional Example: How many milliliters of 0.45 M HCl will neutralize 25.0 mL of 1.00 M KOH?

19.1 Acid-Base Theories> 17 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. V. Salts in Solution A. Salt Hydrolysis Recall that some salts can hydrolyze water – remove hydrogen ions from or donate hydrogen ions to water (Hydrolysis of Salts Lab)  salt hydrolysis.  salts that produce acidic solutions have positive ions that release hydrogen ions to water  salts that produce basic solutions have negative ions that attract hydrogen ions from water

19.1 Acid-Base Theories> 18 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. V. Salts in Solution Example: ammonium chloride  Ammonium chloride completely ionizes in water: NH 4 Cl (aq)  NH + 4(aq) + Cl - (aq)  the ammonium ion is a strong enough acid to donate a hydrogen ion to a water molecule: NH + 4(aq) + H 2 O (l)  NH 3(aq) + H 3 O + (aq)  the resulting H 3 O + ions make the solution somewhat acidic

19.1 Acid-Base Theories> 19 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. V. Salts in Solution Strong acid + Strong base  neutral solution Strong acid + Weak base  acidic solution (salt’s cation releases hydrogens to water) Weak acid + Strong base  basic solution (salt’s anion attracts hydrogens from water)

19.1 Acid-Base Theories> 20 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Day Carbonic acid is a weak acid, if it reacts with a strong base like NaOH, what type of solution will result? 2. Write an equation for the ionization of sodium bicarbonate. 3. Write an equation for the reaction between bicarbonate ions and water NaHCO 3  Na + (aq) + HCO 3 - (aq) HCO 3 - (aq) + H 2 O (l)  H 2 CO 3(aq) + OH - (aq)

19.1 Acid-Base Theories> 21 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Day Arrhenius acid Hydrolysis K w -log[H + ] Lewis base Universal Indicator Titration Bronsted-Lowry acid K a Strong base Concentrated acid Neutralization reaction Standard solution

19.1 Acid-Base Theories> 22 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. Day page 675 #s – due tomorrow (Friday 4-27) TEST WILL BE FRIDAY 5-4 DAY 6!!!