You are attempting to purify a compound via recrystallization. You prepare the process through the following method: 1) Dissolve the material in a minimal amount of hot EtOH. 2) Slowly add hot water until the compound is slightly cloudy. 3) Add a small amount of ELOH until the solution is just clear (still hot). 4) Cool to RT. Upon cooling to RT you notice that the compound is not precipitating out of solution. You decide to boil off some ethanol. Upon completing this step and cooling to RT you notice that the compound i precipitating out as desired! In which solvent is your compound the least soluble? Ethanol O Water O The ethanol water mixture Insoluble in all of these solvents

You are attempting to purify a compound via recrystallization. You prepare the process through the following method: 1) Dissolve the material in a minimal amount of hot EtOH. 2) Slowly add hot water until the compound is slightly cloudy. 3) Add a small amount of ELOH until the solution is just clear (still hot). 4) Cool to RT. Upon cooling to RT you notice that the compound is not precipitating out of solution. You decide to boil off some ethanol. Upon completing this step and cooling to RT you notice that the compound i precipitating out as desired! In which solvent is your compound the least soluble? Ethanol O Water O The ethanol water mixture Insoluble in all of these solvents

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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The followings methods are useful to induce crystallization EXCEPT adding a small crystal of the desired compound, called a seed crystal, to the solution adding anhydrous potassium carbonate to the solution and cooling it in an ice bath scratching the inner wall of the Erlenmeyer flask with a glass stirring rod reheating the solution to boiling to boil off some of the solvent, and then allow the solution to cool to room temperature again to effect crystallization
An ideal solvent to use for recrystallization is one that: Group of answer choices dissolves the desired compound in ice-cold water temperature but does not dissolve the desired compound at its boiling temperature. a solvent in which the desired compound dissolves at any temperature. a solvent that reacts with the desired compound. dissolves the desired compound at its boiling temperature but does not dissolve the desired compound in ice-cold temperature.
b) Will the sample be contaminated with any of the impurities? Calculate the percent purity of the initial sample (in terms of compound A) - ( i.e. express the amount of compound A in the initial sample as a percentage of the mass of initial sample). Calculate the percent purity of the final sample (in terms of compound A) - (i.e. express the amount of compound A in the final sample as a percentage of the mass of final sample). Did the recrystallization procedure result in an increase of the percent purity of compound A in the sample? Comment on the results.
Draw an outline of the recrystallization process- Assume all types of Impurities(Soluble, Insoluble and colored) are present.
Please answer this question as fast as you can please and tahnk you. I will afterwards write an wonderful review on solving the question. Thank you. Why is it important for us to leave the water for 5 minutes and determine the water's temperature? The density of water will vary with temperature. You want the water to equilibrate to room temperature in order to maintain consistent results. You want to wait so that the dissolved solids in the water settle to the bottom of the flask. It is impossible to determine the density of water below 20 °C with plastic beakers and cylinders so you need to wait for the water to warm up. It's not that important, we just want to stretch out the time of the experiment.
Table 1. Solubility Tests. Functional Group Observations (specify type if any) Sample in concentrated (+/-) H2SO4 Color orange Hydroxyl group Hydroxyl group Hydroxyl group 1-butanol Color orange 2-butanol Color orange diisopropyl ether Look at the structures of compounds tested for solubility in concentrated H2SO4. What generalization can be made for a substance to be soluble in concentrated H2SO4 ?
Q1. Give three criteria for a good recrystallization solvent. Q2. You want to purify 10 grams of benzoic acid that has been contaminated with 0.2 g of salicylic acid. You are given the following data: Solubility in water at 20 °C Solubility at 100 °C (g/10 ml) Compound (g/10 ml) Benzoic Acid 0.029 0.680 Salicylic Acid 0.680 0.029 0.22 6.67 a) What volume of Boiling water is needed to dissolve the 10 g of benzoic acid? (show calculations) b) How much benzoic acid will crystallize after cooling to 20 °C (show calculations) c) Will any salicylic acid crystals form? Why or why not? (show calculations/ reason for answer) d) What is the maximum amount of benzoic acid that could be recovered in the first crop of this recrystallization? (Show calculations) e) How can you prove the purity and identity of the purified Benzoic acid?
Using recrystallization techniques, a student attempts to purify 0.50 g of compound H. Based on the solubility of H in the chosen solvent at collection temperature, the maximum percent recovery is 82%. The student obtains 0.396 g of purified crystals. What is their percent recovery? Group of answer choices 41% 64% 79% 82% 97% none of these
Chemistry Which lab technique(s) can be performed on solid, somewhat soluble samples? Melting Range Determination or Recrystallization. Melting Range Determination. Not Recrystallization. Neither Recrystallization nor Melting Range Determination. Recrystallization. Not Melting Range Determination.
Consider the following scenario: You obtain an Unknown Sample from the Stockroom. You begin testing the solution through the steps outlined in the flowchart of the experiment’s PDF file. You first add HCl and centrifuge your mixture. You observe the formation of a white precipitate in the bottom of the test tube. After pouring off the supernatant liquid, you add hot water to the white precipitate. Addition of the hot water dissolves some of the precipitate, but some white precipitate still remains on the bottom of the test tube. You pour off the supernatant liquid, and add ammonia (NH3) to the remaining precipitate. You now observe the formation of a gray-black precipitate. Which of the following is a valid conclusion to draw at this point? Select one: 1. Hg22+ is definitely present. 2. Pb2+ is definitely present. 3. Ag+ could be present, or Hg22+ could be present, or BOTH could be present. 4. Ag+ is definitely present
experiment A pair of 100 mL samples of water are taken from a well bored into a large underground salt (NaCl) deposit. Sample #1 is from the top of the well, and is initially at 32 °C. Sample #2 is from a depth of 50. m, and is initially at 42 °C. Both samples are allowed to come to room temperature (20. °C) and 1 atm pressure. An NaCl precipitate is seen to form in Sample #1. Two 250 mL samples of water are drawn from a deep well bored into a large underground salt (NaCl) deposit. Sample #1 is from the top of the well, and is initially at 42 °C. Sample #2 is from a depth of 150 m, and is initially at 8 °C. Both samples are allowed to come to room temperature (20 °C) and 1 atm pressure. An NaCl precipitate is seen to form in Sample #1. predicted observation (choose one) A bigger mass of NaCl precipitate will form in Sample #2. A smaller mass of NaCl precipitate will form in Sample #2. The same mass of NaCl precipitate will form in Sample #2. No precipitate will form in Sample #2. I…
A forensic chemist is given a white powder by the investigator of a crime scene. The investigator wants to know if the powder is a pure substance or a mixture. The chemist dissolves some of the powder in deionized water making a clear solution. She finds that a precipitate forms when she adds an excess aqueous solution of sodium chloride. She filters the precipitate and washes it several times with deionized water. To this filtrate she then adds an aqueous solution of sodium carbonate. A precipitate forms. Question: Draw two pictures representing a molecular / atomic / ionic view of what occurred when a precipitate formed with the addition of sodium chloride solution. Choose the type of particle that is the most appropriate for this reaction. Place charges on any ions indicating charge values (+1, -2, etc.) when they are known. If charges are unknown indicate whether the ion is positive or negative. Clearly indicate which picture represents before the reaction occurs. Should…