# chemlab4 - NAME and ID Number Christina Hong#0862620 LAB...

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Unformatted text preview: NAME and ID Number: Christina Hong #0862620 LAB PARTNER:Travis Hyunh Quiz Section: AR Total Points = 60 (5 notebook, 55 template) PURPOSE AND METHOD DATA AND CALCULATIONS A. Standardization of NaOH Run 1 Run 2 Run 3** Mass of KHP, g 0.134 g 0.140 g 0.142 g moles KHP 6.56x10^-4 6.86x10^-4 6.95x10^-4 Initial buret reading, mL 0.00 mL 0.00 mL 0.00 mL Final buret reading, mL 7.25 mL 6.80 mL 7.25 mL mL NaOH titrated 7.25mL 6.80mL 7.25mL L NaOH titrated 0.00725L 0.00680L 0.00725L [NaOH], moles/L 9.048x10^-2 1.009x10-1 9.586x10^-2 Average, [NaOH] 9.574x10^-2 M 3 pts Table 1: NaOH Standardization How are the solubility products (K sp ) of KHP at various temperatures determined? ( 3 pts ) The solubility products (Ksp) of KHP at various temperatures are determined First I take the average [NaOH] from part A of this experiment. Then I calculate the NaOH mL added to the solution. I change mL to L, so I can use this value to determine the mmoles HP- of one trial. I know that the ratio of HP- and NaOH is the 1:1, the same, so I can say that mmoles NaOH=mmoles HP-. Then I use the equation mmoles HP-=([NaOH] average X Liters of NaOH added)/(1.0x10^-3 moles) to determine the mmoles HP-. Next I take the mmoles HP- and divide it by the mL of HP- used in the titration, which is 1mL, in order to determine the molarity of HP-. The equation for this is Molarity HP-= mmoles HP-/1mL HP- added. Finally, since the ratio of HP and NaOH is 1:1, I use the equation Ksp=[HP-][NaOH]=[HP-]^2 to determine the Ksp of KHP at a certain temperature. How is K sp in a saturated solution of KHP in 0.50 M KCl determined? (3 pts ) First, I calculate the average molarity of HP- from the titration of RT KHP in KCl with NaOH(aq) in part C. Then, I multiply the average molarity of HP- by the [K+] in original solution, in order to determine the Ksp in a saturated solution of KHP in 0.50 M KCl. There are several steps to calculate the [K+] in original solution. First I calculate the [K+] in measured solution. In order to do so, I have to use the equation formulated from the graph in part C and the intensity found from during the flame photometer part of the experiment in order to calculate "x" (this is the [K+] in measured solution). After calculating the [K+] in measured solution, I use this value and multiply it by the dilution factor, which is 2,500 to determine the [K+] in original solution. Finally, I multiply this [K+] value by the average molarity of HP- to get the desired Ksp. EXPERIMENT 4: THERMODYNAMICS II THE TEMPERATURE DEPENDENCE OF THE SOLUBILITY PRODUCT, HEAT OF SOLUTION, AND ENTROPY OF SOLUTION OF POTASSIUM HYDROGEN PHTHALATE Show the calculation for determining [NaOH]for one of the runs. May be typed or NEATLY handwritten....
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chemlab4 - NAME and ID Number Christina Hong#0862620 LAB...

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