CHEM 102 1nd Edition Lecture 27Outline of Last Lecture I. Find KaII. Henderson-HasselbalchIII. BuffersOutline of Current Lecture I. TitrationsII. Acid-Base IndicatorsIII. IndicatorsIV. Titration CurvesCurrent LectureI. Titrationsa. A titration is the process of reacting a solution of unknown concentration with one of known concentrationb. A known concentration will be the standard solution.c. The titrant is the solution that is added.d. Equivalence point is the point in the titration where the correct number of moles of reactant is presente. Endpoint is the point where the indicator changes colorII. Acid-Base Indicatorsa. Used to indicate the pH of a solutionb. Typically weak organic acids where the ionized and unionized forms exhibit different colorsc. Ka = [In-][H30+]/[HIn] which gives [In-]/[HIn] = Ka/[H30+]d. Ration depends on the pH and KaIII. Indicatorsa. Methyl Redi. Purple until 5ii. At 5/6 pink and orangeiii. 7 to 11 = yellowb. Bromothymol Bluei. Yellow from 1 to 6ii. At 7, aquaThese 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.iii. 8 to 11, bluec. Phenolphthaleini. Clear from 1 – 8ii. Light pink at 9iii. 10 to 11 purpleIV. Titration Curvesa. Obtained by plotting solution pH as a function of the amount of titrant addedb. Illustrates how solution pH changes during the course of a titrationc. Characteristic features vary depending on nature of reactantsd. Useful in determining a suitable
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