Chem 1120 1st Edition Lecture 12 Outline of Last Lecture I. Detecting RadioactivityII. Energy Changes in Nuclear ReactionsIII. Fission and FusionA. Controlled vs Uncontrolled Fission IV. Radiation in the Environment and Living MatterOutline of Current Lecture I. Bronsted-Lowry Acids and BasesII. Autoionization of WaterIII. pH ScaleCurrent LectureI.Arrhenius Acids = a substance that directly yields H+ ions when dissolved in water Arrhenius Bases = a substance that directly yields OH- ions when dissolved Bronsted-Lowry Acid-Base Defintion:Acid = proton donor, any species which donates a H+These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Base = proton acceptor, any species that accepts a H+An acid-base reaction can now be viewed from the standpoint of the re-actants and the productsAn acid reactant will produce a base product and the two will constitutean acid-base conjugate pairConjugate acid-base pair = two species whose formulas differ by a sin-gle H+HCN/CN- H2O/H3O+ H2O/OH-Example: Which of the following is the conjugate acid of each?Which of the following is the conjugate base of each?On the next page, identify the Bronsted acids and bases on the left hand sideand the conjugates on the right hand side. Strong acids are strong electrolytes and therefore ionize completely in waterWeak acids are weak electrolytes and do not ionize completely in waterSome substances have negligible acidity in waterThe stronger an acid, the weaker its conjugate base and the weaker anacid, the stronger its conjugate base. The same is true for a base and its con-jugate acid.Most common strong acids = HCl, HBr, HI, HClO3, HClO4, HNO3, H2SO4 Most common strong bases = LiOH, NaOH, KOH, (group 1a metals with hydroxide), Ca(OH)2, Ba(OH)2, Sr(OH)2, (heavy group 2a metals with hydrox-ide)In any acid-base reaction, the equilibrium will favor the reaction that moves the proton to the stronger base II. Water is very amphoteric, so in pure water, a few molecules act as acidsand a few act as bases Water is a very weak electrolyteThe ion-product constant for water is Kw = [H+][OH-] = 1.0 X 10^-14 @ 25oExample: The H+ concentration in the human stomach is about 0.3 M. What is the OH- concentration?Solution: Kw = [H+][OH-] = 1.0 X 10^-14[OH-] = Kw/[H+] = 1.0 X 10^-14 / 0.3M = 3 X 10^-14 M III.pH = -log10[H+]Example: The pOH of a solution is 9.40. Calculate its H+
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