Titration • http://www.youtube.com/watch?v=WKLkpoo5Gbo • http://www.youtube.com/watch?v=8UiuE7Xx5l8
Titrations Titration: the process of analyzing composition by measuring the volume of one solution needed to completely react with another solution. Usually the reaction of an acid with a base.
Titrations Analyte: the solution of unknown concentration but known volume. Titrant: the solution of known concentration. Analyte + Titrant → Products
Titrations Equivalence Point: the point at which exactly the right volume of titrant has been added to complete the reaction. Indicator: substance that changes color when an excess of titrant has been added (phenolphthalein).
Solution Stoichiometry • Solution Stoichiometry uses molarity as a conversion factor between volume and moles of a substance in a solution.
Titrations Titration Calculations: • Find the number of moles of titrant added to reach the endpoint. • Determine the moles of analyte that must have been present (use stoichiometric coefficients). • Determine the concentration of analyte that must have been present in the flask (use the volume of analyte). • Calculate the concentration of analyte in the original sample.
Titrations Example #1: 14.84 mL of an HCl solution of unknown concentration is titrated with standard NaOH solution. At the equivalence point, 25.0 mL of the 0.675 M NaOH has been added. Calculate the concentration of the HCl solution. NaOH + HCl → NaCl + H2O Titrant = ? Analyte = ?