Post-Lab Question(s) 1. Write an experimental procedure describing how to use recrystallization technique to purify an unknown with two impurities with the following hypothetical properties: Cold Solvent 1 (20 °C) Insoluble Insoluble Hot Solvent 1 (95 °C) 6.0 g /100 mL 5.0 g/ 100 mL Cold Solvent 2 Hot Solvent 2 |Impurity A |Impurity B (20 °C) 0.80 g/ 100 mL Insoluble (95 °C) 4.8 g/ mL Insoluble Include needed amounts in your procedure.

Post-Lab Question(s) 1. Write an experimental procedure describing how to use recrystallization technique to purify an unknown with two impurities with the following hypothetical properties: Cold Solvent 1 (20 °C) Insoluble Insoluble Hot Solvent 1 (95 °C) 6.0 g /100 mL 5.0 g/ 100 mL Cold Solvent 2 Hot Solvent 2 |Impurity A |Impurity B (20 °C) 0.80 g/ 100 mL Insoluble (95 °C) 4.8 g/ mL Insoluble Include needed amounts in your procedure.

Principles of Instrumental Analysis

7th Edition

ISBN:9781305577213

Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch

Chapter33: Automated Methods Of Analysis

Section: Chapter Questions

Problem 33.8QAP

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Make a schematic diagram for the procedure below: B. % SO3 determination Dry the soluble sulfate sample at 100° C for 1-2 hours, and cool in desiccator. Weigh out 0.5 – 0.7 g (± 0.3 mg) duplicates sample. Transfer to 400-mL beakers. Dissolve each in 200 mL of dist. H2O + 4 mL of 6 m HCl. Precipitant is prepared by dissolving 1.3 g BaCl2 ∙ H2O in 100 mL water. Filter if solution is not perfectly clear. Heat the BaCl2 solution and sulfate sample solution nearly to boiling, and then add the entire amount to the HOT sulfate sample solution while stirring vigorously. Wash stirring rod with distilled water and include washings in your final mixture. Digest by letting stand 1-2 hours. Overnight standing is acceptable. Filter through an ash less filter paper of fine porosity (Whatman no. 42). Slowly pour the supernatant liquid through the filter paper.
Rinse and fill the buret with 0.100 M HCl solution. Transfer accurately 25.0 mL of saturated calcium hydroxide solution (2g of calcium hydroxide per 100 ml of water) into two separate E-flasks. Add 2 drops of phenolphthalein to each flask and titrate each solution until the pink color disappears. Voume of HCl used: Trial 1= 6.80ml; Trial 2 = 6.30mL Determination of solubility and Ksp of calcium hydroxide 2. Compute for the moles of H+ used and the moles of OH- present. moles of H+ used = (concentration of HCl) × (volume of HCl used)moles of OH- = moles of H+ used 3. Construct an ICE table for the reaction.4. Calculate the molar solubility (in mol/L) of OH- and Ca2+.5. Determine the solubility of Ca(OH)2 in g/L. (MM of Ca(OH)2 = 74.096 g/mol)6. Calculate the Ksp of Ca(OH)2.7. Compute for the percent error of the experimental value for Ksp of Ca(OH)2 with the literature value.(Ksp of Ca(OH)2 = 8.0 × 10-6 at 25°C)
Rinse and fill the buret with 0.100 M HCl solution. Transfer accurately 25.0 mL of saturated calcium hydroxide solution (2g of calcium hydroxide per 100 ml of water) into two separate E-flasks. Add 2 drops of phenolphthalein to each flask and titrate each solution until the pink color disappears. Using the titration data for the determination of solubility and Ksp of calcium hydroxide: Parameter Trial 1 Trial 2 Final Buret Reading (mL) 5.80 12.20 Initial Buret Reading (mL) 0.00 5.80 Temperature (in celcius) 25 25 Construct an ICE table for the reaction
You are given a container with Na3PO3 that is reportedly contaminated. You are asked by your supervisor to determine the percent purity of that sample in order to know the next measures to be taken by the plant. The following are the procedures that you need to do: a. Dissolve sample weighing 1 g in 35 mL water. b. Prepare solution with 45 mL 3% w/v HgCl2, 30 mL 10% w/v C2H3NaO2 and 10 mL CH3COOH. c. Digest sample then filter then rinse the precipitate that weighs 0.2857 g. d. Compute for the % purity.
1. Rinse and fill the buret with 0.100 M HCl solution. Transfer accurately 25.0 mL of saturated calcium hydroxide solution (2g of calcium hydroxide per 100 ml of water) into two separate E-flasks. Add 2 drops of phenolphthalein to each flask and titrate each solution until the pink color disappears. Using the titration data for the determination of solubility and Ksp of calcium hydroxide: Parameter Trial 1 Trial 2 Final Buret Reading (mL) 5.80 12.20 Initial Buret Reading (mL) 0.00 5.80 Temperature (in celcius) 25 25 Determine the following:a. Construct an ICE table for the reaction.b. Calculate the molar solubility (in mol/L) of OH- and Ca2+.c. Determine the solubility of Ca(OH)2 in g/L. (MM of Ca(OH)2 = 74.096 g/mol) and the Ksp of Ca(OH)2.
Extraction of Caffeine Post-lab 4. What does it mean for two solvents to be immiscible? 5. On the report sheet, you calculated your percent recovery of caffeine. a. If your percent was less than 90%, give at least one reason why it was less. b. A group of students have their percent yield more than 100%, give at least one reasonwhy it was more than 100%. Do NOT simply say “human error.” Be specific about the typesof errors (human or otherwise) that may have occurred, leading to a recovery more than eorequal to 100% (Is this possible Why?) 6. Based on what you observed during this experiment, is dichloromethane denser OR lessdense than water? Explain your reasoning. 7. Based on what happened in this experiment, is caffeine more soluble in water OR moresoluble in dichloromethane? Explain your reasoning. 8. Ethanol is miscible with water. (After all, alcoholic beverages don t separate into an “alcohol‟layer” and a “water layer.”) Assuming that caffeine is soluble in ethanol, could…
profile-image Time remaining: 00 : 09 : 27 Chemistry A group was given the responsibility of performing a recrystallization experiment in their laboratory to see if the three newly found solvents could purify and separate a mixture including compounds A and B. The following are the solubilities of the two compounds in g/100 mL of hot and cold solvents:Solubility in g/100 mL solvent A B B Solvent Hot Cold Hot Cold 1 4.60 1.10 5.30 1.90 2 6.40 5.80 8.40 1.10 3 3 9.70 3.30 6.80 What is the %recovery and %purity of A and B in the chosen solvent? Show solutions pls
25 ml of pickled brine was taken from an apple pickled with vinegar and diluted to 500 ml, 25 ml of this was taken and acidity was determined with 0.2 N (Factor: 1.05) NaOH. In the main trials, 6.3 ml - 6.5 ml - 6.9 ml, respectively, 0.1 ml base was used in the analysis without using the sample.For example, how many ppm is its acidity?
You're trying to finish preparing a compound that a coworker had to stop in the middle of making. They added 20g of pure benzoic acid to 90g of ointment that already contained 6% benzoic acid. What is the final concentration of the mixture in percent strength? Using Alligation method.
1) How many milliliters of 70% ethanol and 20% ethanol must be mixed to prepare 500ml of 30% ethanol? 2) A gaseous blend of nitric oxide and nitrogen (NOmax) contains 0.09% v/v nitric oxide (NO) and 99.92% v/v nitrogen. Express the strength of nitric oxide in PPM (round to whole number) 3) The ratio strength of a 10mL vial of neostigmine methylsulfate injection USP is 1:1500.Calculate the amount of neostigmine methylsulfate in milligrams contained in the 10mL vial. (Round to the whole number).
Anion Test - Sulfate (SO42-) Procedure : Mix 5 drops of SO42- (Na2SO4 0.5 M) with 5 drops of HCl acid 1 M, add another 2 drops of SO42- until it excess. Heat the mixture in steam bath until excess CO2 release from it. Add few drops of BaCl2 1 M to complete the precipitation and finally leave the mixture for a while. Results : White precipitate is obtained at the test tube after adding BaCl solution to complete the precipitation. What is the Chemical equation involved and Discuss the Sulfate test?
(Please answer all questions) 5-33. What are some advantages of using column chromatography to purify reaction products in the microscalelaboratory? 5-34. Discuss the similarities and dissimilarities of TLC, paper, and column chromatography. 5-35. Discuss the similarities and dissimilarities of HPLC and gas chromatography. 5-36. (a) What are the main advantages of using flash chromatography?(b) How can TLC be used in connection with flash chromatography? 5-37. Using the information presented on the right, please identify and explainwhich spot has an Rf value of 0.5.