CHEM 102 1nd Edition Lecture 26Outline of Last Lecture I. Ka pHII. Percent HydrolysisIII. pH of SaltIV. Polyprotic AcidV. BuffersVI. pH of 0.30 M HC2H3O2VII. Common-Ion EffectVIII. ShortcutOutline of Current Lecture I. Find KaII. Henderson-HasselbalchIII. BuffersCurrent LectureI. Find Ka- HAc H+ + Ac-- I 0.32 0.28- C –x x 0.28 +x- Ka = 1.8e-5 = (x)(0.28+x)/0.32-x- Ka = 1.8e-5 = (x)(0.28)/0.32- X = 2.06e-5 = [H+] - pH = 4.69II. Henderson-Hasselbalch - pH = pKa + log([X-]/[axid])III. Buffers - Ph of 0.30 M HAc + 0.30 M NaAc that has 0.020 mol of NaOH added- NaOH will react with something, but what does it react with?- NaOH would react with HAc- The acid and base reaction goes to completion and are not in equilibrium.- OH- which would come from NaOH would react with H+ Decreases H+ Shift the weak acid equilibrium to the rightThese 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.- Steps to determine pH React the two compounds Use an ICF table Change the moles on the F line to molarity by dividing by volume Get pH from F line If a buffer remains, use Henderson If only a strong acid or base is left, get pH from
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