CHM1045 Lecture 12Outline of Last LectureI. Conduct electricity in solution?II. Ionization of acetic acidIII. Precipitation ReactionsIV. Precipitation of Lead Iodidei. Example 1I. Writing net ionic equationsii. Example 2Outline of Current LectureII. Properties of AcidsIII. Properties of BasesIV. AcidsV. Neutralization ReactionVI. Neutralization Reaction Involving a Weak ElectrolyteVII. Neutralization Reaction Producing a GasVIII. Oxidation-Reduction ReactionsCurrent LectureProperties of Acids- Have a sour taste. Vinegar owes its taste to acetic acid. Citrusfruits contain citric acid- Cause color changes in plant dyes- React with certain metals to produce hydrogen gas- 2HCl (aq) + Mg (s) MgCl2 (aq) + H2 (g)- React with carbonates and bicarbonates- to produce carbon dioxide gas.Properties of Bases- Have a bitter taste- Feel slippery. Many soaps contain bases.- Cause color changes in plant dyes.- Aqueous base solutions conduct electricity.- Arrhenius acid is a substance that produces H+ (H3O+) in water- HCl + H20 H3O + Cl-- Hydronium ion, hydrated proton, H3O+ Acids- A Brønsted acid is a proton donor- A Brønsted base is a proton acceptorNH3 (Base) + H2O (acid) NH4+ + OH- - A Brønsted acid must contain at least one ionizable proton!Monoprotic acidsHCl H+ + Cl- Strong electrolyte, strong acidHNO3 H+ + NO3-Strong electrolyte, strong acidCH3COOH H+ + CH3COO-Weak electrolyte, weak acidDiprotic acidsH2SO4 H+ + HSO4Strong electrolyte, strong acidHSO4- H+ + SO42-Weak electrolyte, weak acidTriprotic acidsH3PO4 H+ + H2PO4-Weak electrolyte, weak acidH2PO4- H+ + HPO42-Weak electrolyte, weak acidHPO42- H+ + PO43- Weak electrolyte, weak acidExample 1:Classify each of the following species in aqueous solution as a Brønsted acid or base:a. HBr -- HBr H+ Br-(aq) , therefore bronsted acidb. NO-2----- NO-2(aq) + H+ HNO2 (aq) Bronsted acidc. HCO-3---- HCO3- (aq) H+ CO2/3- ----- Bronsted AcidNeutralization Reactionacid + base salt + waterHCl (aq) + NaOH (aq) NaCl (aq) + H2OH+ + Cl- + Na+ + OH- Na+ + Cl- + H2OH+ + OH- H2ONeutralization Reaction Involving a Weak Electrolyteweak acid + base salt + waterHCN (aq) + NaOH (aq) NaCN (aq) + H2OHCN + Na+ + OH- Na+ + CN- + H2OHCN + OH- CN- + H2OExample 2:Write molecular, ionic, and net ionic equations for each of the following acid-base reactions:(a) hydrobromic acid(aq) + barium hydroxide(aq)(b) sulfuric acid(aq) + potassium hydroxide(aq)a.) 2HBR(aq) + Ba(OH)2 BaBr2 + 2H2O ---- molecular2H+ 2Br- + Ba2+ + 2OH- Ba2+ + 2Br- + 2H2O--- ionicH+ + OH- H2O --- net ionicb.) H2SO4 + 2KOH K2SO4 + 2H2O--- molecularH+ + HSO4 + 2K + 2OH- 2K + SO 2/4 + 2H2O --- ionicH+ +HSO4- + 2OH- + SO2/4 + 2H2O --- net ionicNeutralization Reaction Producing a Gasacid + base salt + water + CO22HCl (aq) + Na2CO3 (aq) 2NaCl (aq) + H2O +CO22H+ + 2Cl- + 2Na+ + CO32- 2Na+ + 2Cl- + H2O + CO22H+ + CO32- H2O + CO2Oxidation-Reduction Reactions- (electron transfer reactions)2Mg 2Mg2+ + 4e-Oxidation half-reaction (lose e-)O2 + 4e- 2O2-Reduction half-reaction (gain e-)2Mg + O2 + 4e- 2Mg2+ + 2O2- + 4e-2Mg + O2
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