thermo II lab (post-laptop death)

thermo II lab (post-laptop death) - Name: ID Number: Emily...

Info iconThis preview shows pages 1–2. Sign up to view the full content.

View Full Document Right Arrow Icon
Name: Emily Tsiao Quiz Section: AD ID Number: 930609 Lab Partner:Hayley Smith 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 7.50E-05 84 1 7.50 E-5 0.75 Standard 2 1.50E-04 152 2 1.50 E-4 1.50 Standard 3 2.25E-04 222 3 2.25 E-4 2.25 Standard 4 3.00E-04 318 4 3.00 E-4 3.00 Standard 5 3.75E-04 373 5 3.75 E-4 3.75 Intensity 23.2 229.8 3 pts slope 9.92E+05 y-intercept 6.6 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 How are the solubility products (K sp ) of KHP at various temperatures determined? ( 3 pts ) In order to calculate the Ksp of KHP at various temperatures, we titrate saturated KHP solutions at various temperatures with a standardized NaOH solution. Using data from these titrations, we can calculate the moles of NaOH added at equilibrium, which is equal to the moles of KHP in the solution. then, using the amount of KHP in the original solution, we can determine the molarity of HP^- in each of the solutions. Because each solution is saturated and KHP dissociates in a 1:1 ratio, we know that [HP^-] is equal to [K^+], thus we can calculate Ksp using the equation: Ksp =[HP ^- ][K^+]. How is K sp in a saturated solution of KHP in 0.50 M KCl determined? (3 pts ) In order to calculate Ksp of a saturated KHP solution in the presence of a common ion (from 0.50 M KCl), we calculate [K^+] and [HP^-] individually. The [HP^-] is found by titrating the KHP/KCl mixture with the standardized NaOH solution in the same way as Part B. To calculate [K^+], though, we compare the intensity of a diluted KHP/KCl solution (using a flame photometer) to a group of standard solutions. In creating a calibration curve of the standard solutions, we can calculate [K^+] of the diluted sample from the intensity reading, Using this value, we can calculate the [K^+] of the initial solution by mathematically undoing the solution. 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, that you have not plagiarized any part of this lab report, and that all calculations and responses other than the reporting of raw data are your own independent work. Failure to sign this declaration will cost you 5 points.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 2
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 06/03/2010 for the course CHEM 152 taught by Professor Chiu during the Spring '08 term at University of Washington.

Page1 / 4

thermo II lab (post-laptop death) - Name: ID Number: Emily...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online