Chem152_Titration2_Report

Chem152_Titration2_Report - Name and ID Number: Sienna...

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Page 1 Name and ID Number: Sienna Hiebert 0725998 Section: BB Lab Partner: Total Points = 60 pts PURPOSE AND METHOD DATA, CALCULATIONS AND GRAPHS A: Standardization of NaOH using KHP Table 1: Data for Calculation of [NaOH] Run #1, 1 pt Run #2, 1 pt Run #3, 1 pt** Mass of KHP 0.406g Mass of KHP 0.432 g Mass of KHP 0.448 g Molar Mass, KHP 204.22g/mole Molar Mass, KHP 204.22g/mole Molar Mass, KHP 204.22 g/mole Initial buret reading 0mL Initial buret reading 0 mL Initial buret reading 0 mL Final buret reading 32.3mL Final buret reading 23.8 mL Final buret reading 23.6 mL mL Titrated 32.3mL mL Titrated 23.8 mL mL Titrated 23.6 mL L Titrated 0.03L L Titrated 0.02 L L Titrated 0.02 L [NaOH] 0.0650 M [NaOH] 0.0890 M [NaOH] 0.0930 M Average [NaOH] 0.0823 M EXP 1: ACID-BASE TITRATION HELP KHP is potassium hydrogen phthalate, see manual for structure and molar mass. Review stoichiometry of reaction in the lab manual. Decide how many significant figures you need in the [NaOH] and format the number accordingly [Format --> Cells --> number --> number (change to desired number of decimal places]. Average =average(range of cells), excel will ignore text. This section has been completed for you as an example. There is no need for you to redo this section. Do not copy this into your lab notebook for your required Purpose & Procedure section - use this as a guide of what to include and write something in your own words. The purpose of this lab is to determine the concentration and dissociation constant of an acetic acid (HOAc) solution. The acid solution will be titrated with ~0.10 M sodium hydroxide while a pH meter is used to monitor the change in pH after each addition of base. The resulting titration curve (plot of pH versus volume of NaOH added) will be used to determine the equivalence point of the titration. Using the data from the titration curve, a derivative plot will be generated, the maximum of which identifies the volume of base added to reach the equivalence point. The volume of base added at the equivalence point, together with the concentration of the base and the volume of acid titrated, will be used to calculate the molarity of the acid according to the following equations: HOAc + NaOH → OAc - + H 2 O + Na + M acid *V acid = M base *V base There are two parts to this lab: (A) Standardization of the NaOH(aq) using potassium hydrogen phthalate (KHP). A known mass of KHP is titrated with NaOH(aq) to a phenolphthalein indicator endpoint. From the moles of KHP and the known stoichiometry of the reaction (1:1), the concentration of NaOH is calculated. (B) Titration of acetic acid, (HOAc) with NaOH(aq). The pH of the HOAc is measured as a function of volume of NaOH added. A plot of pH versus volume of NaOH added and a plot of derivative (slope between adjacent points) versus volume of NaOH are used to determine the equivalence point. The equivalence point is used to calculate the concentration of HOAc and the pH of the mixture prior to the equivalence point is used to determine the acid dissociation constant (K
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This note was uploaded on 04/07/2008 for the course CHEM 152 taught by Professor Chiu during the Winter '08 term at University of Washington.

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Chem152_Titration2_Report - Name and ID Number: Sienna...

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