Chem152_Thermo2_Report

# Chem152_Thermo2_Report - NAME and ID Number Quiz Section AM...

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NAME and ID Number: Lab Partner: Quiz Section: AM Total Points = 60 PURPOSE AND METHOD DATA AND CALCULATIONS A. Standardization of NaOH Run 1 Run 2 Mass of KHP 0.13 0.13 moles KHP 0.000651 0.000651 Initial buret reading, mL 3 3 Final buret reading, mL 9.4 9.54 mL NaOH titrated 6.4 6.54 L NaOH titrated 0.01 0.01 [NaOH], moles/L 0.1018 0.0996 Average, [NaOH] 0.1007 M 4 pts Table 1: NaOH Standardization How are the solubility products (K sp ) of KHP at various temperatures determined? ( 4 pts ) From the chemical equation: KHP (s) <-> K+(aq) + HP- (aq), the Ksp can be determined by multiplying the concentration of [K+] and the [HP-]. Since we know that the K and the HP are in a one to one ratio, if we find one of the concentrations then we can use that same one to call the other concentration. With out experiment we can determine the concentration of HP from the titration of KHP with NaOH. Since from part A we will determine the concentration of NaOH, we can use that information along with the amount of NaOH used to reach equilibrium to determine the mmoles of HP. This value will then be divided by the volume of KHP that was used in that process. How is K sp in a saturated solution of KHP in 0.50 M KCl determined? (4 pts ) Once the saturated solution is made, we will measure its intensity using the flame photomet er We can derive the concentration of K using the linear regression line created from the intensity of the the known concentrations. To determine the concentration of K, we would subtract the y-intercept from the intensity and divide that number by the slope of the linear regression line. Since this solution is created by the dilution of K by a factor of 2500, we will divide the concentration that we get from the graph by 2500 to get the original concentration of K. To determine the concentration of the base, we will titrate a total of three times 3mL of the solution of KCL in KHP. The amount of NaOH used to titrate this solution multiplied by the average concentration of NaOH determined from part A will give us the concentration of OH. EXPERIMENT 4: THERMODYNAMICS II THE TEMPERATURE DEPENDENCE OF THE SOLUBILITY PRODUCT, HEAT OF SOLUTION, AND ENTROPY OF SOLUTION OF POTASSIUM HYDROGEN PHTHALATE By signing below, you certify that you have not falsified data and that you have not plagiarized any part of this lab report. Signature:

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## This note was uploaded on 04/07/2008 for the course CHEM 152 taught by Professor Chiu during the Spring '08 term at University of Washington.

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Chem152_Thermo2_Report - NAME and ID Number Quiz Section AM...

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