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Copy of Chem152_Thermo2_Report_092611

Copy of Chem152_Thermo2_Report_092611 - Name Michelle Bang...

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Name: Michelle Bang Quiz Section: AG ID Number: 1021913 Lab Partner: Tessa Barclay Total Points = 60 (5 notebook, 55 template) PURPOSE AND METHOD DATA AND CALCULATIONS A. Flame emission determination of [K+] in the 0.50 M KCl + KHP (sat) solution Preparation of Standards DATA 50 mL of each standard solution (from prelab) Solution Intensity Standard [K+], (M) mL of stock Standard 1 0.000075 86 1 7.50 E-5 0.75 Standard 2 0.00015 157 2 1.50 E-4 1.50 Standard 3 0.000225 233 3 2.25 E-4 2.25 Standard 4 0.0003 308 4 3.00 E-4 3.00 Standard 5 0.000375 375 5 3.75 E-4 3.75 Intensity 24.4 345 3 pts slope 972000 y-intercept 13.1 Dilution factor 24.4 3.414E-04 2,500 0.010 3 pts B. Standardization of NaOH Run 1 Run 2 Run 3** Mass of KHP, g 0.129 0.13 0.13 moles KHP 0.00063 0.00064 0.00064 Initial buret reading, mL 0.03 0.01 0 Final buret reading, mL 6.24 6.70 6.23 mL NaOH titrated 6.21 6.69 6.23 L NaOH titrated 0.00621 0.00669 0.00623 [NaOH], moles/L 0.101 0.096 0.103 Average, [NaOH] 0.099 M 3 pts C. Titrations of KHP Samples with and without KCl mL of KHP(aq) used in titrations 1.00 mL DO NOT enter the data for the solution with KCl in this table Temperature, K 1/T (in K) 0.0 273.15 0.05 2.45 2.40 0.240 0.240 0.0576 0.00366 -2.854 24.4 297.55 0.05 4.70 4.65 0.465 0.465 0.216 0.00336 -1.532 36.6 309.75 0.01 7.48 7.47 0.747 0.747 0.558 0.00323 -0.583 44.4 317.55 0.00 8.97 8.97 0.897 0.897 0.805 0.00315 -0.217 57.4 330.55 0.03 11.94 11.91 1.190 1.190 1.416 0.00303 0.348 65.4 338.55 0.05 13.49 13.44 1.343 1.343 1.804 0.00295 0.590 3 pts slope -5036 K R 8.315 y-intercept 15.553 41.87 kJ/mol 129.315 J/mol 24.4 0.05 4.70 4.65 0.465 0.465 autofills from Table 5 24.4 0.025 4.67 4.645 0.464 0.464 24.4 0.025 4.40 4.375 0.437 0.437 Average M 0.455 mL of KHP(aq) used in titrations 1.00 mL 2 pts 0.207 (from Table 5 and two more replicates) 24.4 0.00 7.57 7.57 0.757 0.252 24.4 0.00 7.77 7.77 0.777 0.259 24.4 0.01 7.95 7.94 0.794 0.265 Average M: 0.259 mL of KHP(aq) in KCl used in titrations 3.00 mL 2 pts 0.221 4 pts RESULTS AND DISCUSSION 2 pts 2. Based on your results at room temperature, what is the solubility of KHP in g/L 3 pts 4 pts 4 pts 3 pts How do your results compare (calculate and comment on % difference)? 2 pts Table 1 : Volume of 5.00x10 -3 M needed to make Table 2 : Flame Photometer Data [K + ], (M) Temperature, o C KHP(sat) in 0.50 M KCl M -1 Table 3 : Flame Emission Determination of [K + ] in the original sample Temperature, o C [K + ] in Measured Solution (M) [K + ] in Original Solution (M) Table 4: NaOH Standardization Table 5: Titration Data and Calculations Temperature, o C Initial buret reading (mL) Final buret reading (mL) mL NaOH added mmoles HP - (=mmoles NaOH) Molarity HP - K sp ln(K sp ) J/mol*K H o Soln S o Soln Table 6 : Titration of RT ( no KCl ) solution with NaOH(aq) to determine [HP - ] Temperature, o C Initial buret reading (mL) Final buret reading (mL) mL NaOH titrated
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