Recrystallization with a Single Solvent

Size: px
Start display at page:

Download "Recrystallization with a Single Solvent"

Transcription

1 Experiment: Recrystallization Part II: Purification of Solids In Part I of the recrystallization experiment, you learned about the factors which make a good recrystallization solvent, and you learned how to determine experimentally what solvents might be good ones. In this part of the recrystallization experiment, you will actually use the recrystallization solvent to purify impure solids. Recrystallization with a Single Solvent Often a single solvent is used to recrystallize an impure solid. Once the solvent has been selected, the recrystallization process proceeds by the following steps. Depending on the impurities present, some of these steps may be omitted, and the possibility for such omissions will be the subject of some of the post-lab questions. Dissolving the Solid to be Purified The solid to be purified is placed in an Erlenmeyer flask. This type of flask is used because it allows for vigorous mixing without spilling the sample. Solvent is added to the flask, and the mixture is heated. How much solvent to add varies from recrystallization to recrystallization and depends on the solid and the solvent involved. In general, the quantity of solvent used is determined experimentally. A small amount of solvent is added to the solid and with vigorous swirling is heated to boiling. During this heating, a boiling stick is used. This stick serves the function of a boiling stone, but it can more easily be removed once the solid is dissolved. If the solid does not dissolve at the solvent s boiling point, more hot solvent is added with swirling until the solid has just dissolved at the solvent s boiling point. At this point, you may have to exercise some judgment. Keeping in mind that there may be insoluble impurities present, impurities that will not dissolve at all in the solvent, even at its boiling point, you must decide whether the material that has not yet dissolved is the substance to be purified or an insoluble impurity. If it is the substance being purified, you need to add more solvent to dissolve it. If it is an impurity, you do not want to add more solvent. Doing so will dilute the solution of desired solid, thus reducing the amount of solid that will recrystallize from the solution once it has been cooled. So how are you supposed to know whether to add more solvent or not? One way to tell is to see if the solid remaining undissolved looks different from the solid that you started with. Is it a different color or a different consistency? Another way is to see if the amount of undissolved solid stays the same as more solvent is added. If it does stay the same, then it is probably insoluble impurity. If it dissolves with further addition of solvent, it is probably the solid to be purified. In any event, the bottom line in dissolving the solid is to use as little solvent as is needed to completely dissolve the solid to be purified. Even with this minimum amount of

2 solvent, some of the solid will remain in solution when it is cooled. The more solvent you use, the more solid you will lose. Adding Decolorizing Carbon If the impure solid is colored when it should be white, or if the solution of impure solid is colored and shouldn t be, decolorizing carbon is used. Sometimes called decolorizing charcoal, or by its trade name Norit, decolorizing carbon will adsorb to its surface those impurities that are causing the color. Because the carbon is very powdered and porous it should never be added to a solution that is near its boiling point. This is because the tiny grains of carbon will act like thousands of little boiling stones and cause the solution to boil over. Never add decolorizing carbon to a hot solution. After the hot mixture has been cooled the carbon is added and the mixture is reheated to the boiling point and filtered. Filtering the Hot Recrystallization Mixture The hot recrystallization mixture is filtered by gravity using a stemless or short stem conical glass or plastic funnel. [ Note: Never filter the hot recrystallization solution with a Buchner or Hirsch funnel. Only use these funnels to filter at room temperature or cooler.] This filtration removes any insoluble impurities, and if used, decolorizing carbon. The filter paper used is fluted filter paper. The mixture must be filtered hot, as near the solvent s boiling point as possible. [ Note: It will save you time and yield if you filter the solution into a beaker. When crystallization does occur, it will be easier to scrape the crystals from a beaker than from a flask.] Since the goal of this step is to separate insoluble impurities from the solution containing the desired solid plus soluble impurities, you do not want any crystals to form until the solution has passed through the funnel. To this end, it is helpful if the funnel is heated before the hot mixture is poured onto it. If all goes well, the hot liquid will pass through the funnel, leaving only insoluble impurities and, if used, decolorizing carbon, on the filter paper. At this point you have removed the insoluble impurities. This hot filtration is the trickiest part of the recrystallization procedure, because crystallization may occur in the funnel and in the pores of the filter paper, preventing the hot liquid from passing through. If crystals do form in the funnel, they can be removed by pouring small amounts of boiling solvent through the funnel to dissolve the crystals. If the quantity of crystals in the funnel is too great for this, scrape the solid from the filter paper, put it back into the hot recrystallization mixture, add more boiling solvent, and refilter the solution. Cooling the filtrate After the insoluble impurities have been filtered off, what remains is a filtrate containing the product to be crystallized plus any soluble impurities. At this point, allow the solution to cool and crystals to form. If crystals do not form, try scratching vigorously the side of the beaker with a glass stirring rod to induce crystallization. If they still do

3 not form, try cooling the solution in an ice-water bath. If crystals still don t form, there is too much solvent in the system. At this point you will have to evaporate some of the solvent to concentrate the solution so that crystals will form. Crystals should be medium in size, the kind that grow only at low temperatures. Crystals that grow very quickly, as soon as they hit the beaker after filtration tend to be very small crystals, ones which can adsorb impurities on their surface. Crystals that grow very slowly and large tend to trap impurity-containing solvent inside them. The best crystals are medium in size and grow over a period of minutes, rather than seconds or hours. Filtering the Crystals The crystals are filtered with suction from the solvent containing the soluble impurities using either a Buchner or Hirsch funnel. It is important that filter paper be used that just covers the holes of the funnel. Washing the Crystals By this time, the crystals have been separated from a solution containing the soluble impurities, and the crystals are still wet by this solution. If the procedure were stopped at this point, the solvent would begin to evaporate, leaving behind some of the dissolved soluble impurity. Therefore, the crystals must be washed with a small amount of ice cold solvent. This washing is done directly on the funnel with suction still applied. The clean cold solvent displaces the impurity-containing solution that had been wetting the crystals. Now, when the solvent is evaporated, there will be no soluble impurity left behind. Drying the Crystals After the washed crystals have been removed from the funnel, the solvent must be allowed to evaporate. This should be done for at least 24 hours to be certain that the crystals are dry. It is useful to cover the crystals with a piece of filter paper that will allow solvent to evaporate without allowing dust and other impurities to fall on the purified crystals.

4 The flow diagram below summarizes this purification process. The symbols used in the diagram are: Product, Soluble Impurities, Insoluble Impurities hot solvent, filter solid filtrate Insoluble Impurities solid Product, Soluble Impurities, Solvent cool, filter filtrate cold solvent wash solid Product, trace of Solvent, trace of Soluble Impurities Solvent, Soluble Impurities, trace of Product liquid wash Product, trace of Solvent evaporate solvent Purified Product Solvent, Soluble Impurities, trace of Product Recrystallization with Solvent Pairs There are some solids which cannot be recrystallized from a single solvent. In other words, no single solvent can be found which will not dissolve the solid at room temperature but will dissolve it at the boiling point. When this occurs, chemists employ the technique of solvent pair recrystallization. The solvent pair consists of two solvents that are miscible (soluble in each other in all proportions). The solid to be purified dissolves readily in one of the solvents at room temperature. It does not dissolve readily in the other solvent at any temperature. When the solvents are mixed, the solid dissolves in the solvent pair poorly at room temperature, thanks to the non-dissolving solvent, but well at the boiling point, thanks to the dissolving solvent. Together, the solvent pair dissolves the solid to be purified just like a single recrystallization solvent. Examples of pairs of solvents that are often used in recrystallization can be found online. If there is a problem associated with solvent pair recrystallization, it is finding the best ratio of the two solvents to use. It is not a big problem. For ease of discussion, let s call the solvent in

5 which the solid is soluble, solvent S and the solvent in which the solid is insoluble solvent I. First, we dissolve the solid to be purified in some amount of solvent S. Then we heat the solution to the boiling point. Then, while keeping the solution boiling, we slowly add solvent I. As I is added, the solubility of the solid in the mixed solvent system decreases until the solution becomes saturated. If a little more of I is added, the solvent mixture gets cloudy because the solid begins to precipitate. At this point we add just enough S to redissolve the solid and proceed as with a single solvent recrystallization. Pre-lab Preparation 1. Before coming to lab, carefully go over the Background section for this experiment, your discussion notes on recrystallization, and watch the podcast demonstrating the procedure for recrystallization. Watching the podcast will make the lab faster for you and will help you answer quiz questions your instructor may ask from this podcast. So watch the entire podcast carefully. To find the podcast, go to the Montgomery College homepage and scroll to the very bottom. Under News and Events, select Podcasts (tiny font at the very bottom of the page). Under Browse by Topic, select Science and Technology. View the Podcast labeled Solvent Pair Recrystallization. 2. Carefully go over the procedures to be followed in this laboratory. This will require you to look at the results for the Recrystallization: Part I lab for benzoic acid and determine from your solubility data which organic solvent to use for recrystallizing benzoic acid. Write the solvent that you have selected here. 3. In your notebook, write in tabular form the relevant physical constants for benzoic acid, 1,4-dibromobenzene, and ethanol. 4. Go online and locate and MSDS (Material Safety Data Sheet) for 1,4- dibromobenzene. Review and print this document and attach it to your lab report. Experimental Procedure! Safety Considerations! 1,4-dibromobenzene is carcinogenic. Minimize contact with skin and avoid breathing vapors.! During the solvent pairs experiment, you will be adding decolorizing carbon to the recrystallization mixture and solvent. Be sure that the solvent is not near its boiling point

6 before you add the carbon. If the solution is hot, the solution may violently splash out of the flask. Never add boiling stones to a hot solution.! Also during the solvent pairs experiment, you will be adding hot water (b.p. 100ºC) to hot ethanol (b.p. 65ºC). Add the hot water dropwise because if too much hot water is added to the hot ethanol it might cause the ethanol to boil violently and splash out of the flask. Part 1: Recrystallization of Benzoic Acid from a Single Solvent 1. For this part of the lab, you will compare two recrystallization solvents: water and an organic solvent of your choice (see pre-lab). Weigh two separate 2.0 gram samples of impure benzoic acid. Take enough of this impure solid to take a melting point and put the rest into two separate 125-mL Erlenmeyer flasks. Add boiling sticks to the flasks to prevent bumping when the recrystallization mixture is boiling. 2. Add 10 ml of water to one of the flasks and 10 ml of your selected organic solvent to the other flask and heat the mixtures to boiling on a hot plate. You should also heat flasks with pure solvent so that you can add additional hot solvent as needed in Step Keep adding the respective, hot solvents, while boiling, to the mixture until the solid all dissolves. (No insoluble impurities should be present in this sample.) (You may see some crystals forming on the sides of the flasks, but these can be ignored.) 4. Remove from the heat and allow the solution to cool to room temperature. Crystals should form at this point. After the crystal-solvent mixture has been allowed to sit for 10 minutes, cool the mixture in an ice-water mixture for no more than 5 minutes. Cooling for too long in the ice-water bath may result in crystallization of some of the soluble impurities. 5. Filter the cold mixture with suction and wash the crystals in the funnel with small amounts of your ice cold solvent. 6. Only aqueous waste can be poured down the sink. 7. Remove the crystals from the funnel and place them between two pieces of dry filter paper to allow the crystals to dry. 8. After at least 24 hours, weigh the crystals and determine their melting point and the melting point of the impure solid. Remember to report a melting point range for all samples.

7 Part 2: Recrystallization of 1,4-dibromobenzene from a Solvent Pair 1. Weigh 2.0 grams of impure 1,4-dibromobenzene. Take enough of this impure solid to take a melting point and put the rest into a 125-mL Erlenmeyer flask. Put a boiling stick into the flask to prevent bumping when the recrystallization mixture is boiling. 2. Add 25 ml of ethanol to the flask and bring it to a boil on a hot plate. Cool the solution to below its boiling point. 3. Because the solid mixture was colored and because pure 1,4-dibromobenzene is colorless, add about g of decolorizing carbon to the ethanol-dibromobenzene mixture. Place the flask back on the hot plate and bring to a boil. While heating, warm a stemless funnel on your hot plane. After a minute of boiling, filter the hot solution into an appropriately sized Erlenmeyer flask through fluted filter paper and a heated stemless funnel. 4. If crystallization occurs in the funnel take the steps outlined in the Background section of this experiment to get them out of the funnel. 5. Heat the solution to boiling and dropwise add, with swirling, boiling water to it. Keep adding boiling water to the hot solution until cloudiness appears. At this point, add small amounts of hot ethanol to the boiling mixture until the cloudiness just disappears. 6. Allow the hot solution to cool to room temperature. Crystals should form at this point. After the crystal-solvent mixture has been allowed to sit for 10 minutes, cool the mixture in an ice-water mixture for no more than 5 minutes. Cooling for too long in the ice-water bath may result in crystallization of some of the soluble impurities. 7. Filter the cold mixture with suction and wash the crystals in the funnel with small amounts of ice cold water. 8. Remove the crystals from the funnel and place them between two pieces of dry filter paper to allow the crystals to dry. 9. All ethanol waste will be disposed of in a ethanol waste container in the hood. This includes all filtrates (mother liquors) from the experiment. 10. After at least 24 hours weigh the crystals and determine the melting point of both your purified solid and the melting point of the impure solid. Remember to report a melting point range for both. See Appendix 4 for detailed melting point information. After taking the melting points of the crystals obtained in this experiment, put the remaining crystals of 1,4-dibromobenzene in a test tube and the crystals of benzoic acid in a test tube. Label the test tubes neatly with the name of the compound, your name, your instructor s name and the experimental melting point of the crystals and turn them in to your instructor with your lab report.

8 Post-Lab and Report Requirements 1. Describe the characteristics of a good recrystallization solvent. Also give the characteristics of a good solvent pair system. (Do not simply copy the information provided in the introduction of Recrystallization - Part I. Explain in your own words.) 2. For each of the crystallizations that you carried out, give the grams of dry solid that you recovered, and the melting point ranges of the impure and purified solids. 3. Based on your melting point data, comment on the how well you were able to purify these samples. Also, compare the two solvents used for benzoic acid. Which worked better? How did you decide? 4. Calculate the percentage recovery of each of your recrystallized solids. Explain why you did not get 100% yield. Where did your loss of product occur? Which were avoidable losses and which unavoidable? Percent Recovery = mass of recovered crystals x 100 mass of impure crystals 5. Answer the following questions: a. Under what circumstances would it be reasonable to omit from the recrystallization procedure the step involving filtration of the hot solution through fluted filter paper? b. Under what circumstances would it be acceptable to omit from the recrystallization the addition of decolorizing carbon? c. What would happen to the amount of benzoic acid recovered from your recrystallization if you used too much solvent to dissolve your crystals? Explain your answer. d. Why is it necessary to wait at least 24 hours after filtering them to take a melting point of the recovered crystals? What would be the effect of not waiting? e. In the solvent pair recrystallization that you did in this experiment, you were told to dissolve the impure 1,4-dibromobenzene in 25 ml of ethanol. You mistakenly add 35 ml. Will this error cause you to recover less dibromobenzene than if you had followed directions? Explain your answer.

2. Crystallization. A. Background

2. Crystallization. A. Background 2. Crystallization A. Background Crystallization is one of several available techniques available to purify organic compounds. Unlike other techniques, however, crystallization is specific to the purification

More information

2. Crystallization. A. Background

2. Crystallization. A. Background 2. Crystallization A. Background Crystallization is one of several available techniques available to purify organic compounds. Unlike other techniques, however, crystallization is specific to the purification

More information

Lab 4: Recrystallization

Lab 4: Recrystallization Lab 4: Recrystallization Objectives: - Purify an impure sample of an antibiotic. - Practice the crystallization technique. Introduction: The purpose of this experiment is to introduce the technique of

More information

Lab 4: Recrystallization

Lab 4: Recrystallization Lab 4: Recrystallization Pre Lab Question: (Answer submitted in a separate piece of paper at the beginning of lab) 1. Calculate how much 95% ethanol will be required to dissolve 0.8 g of sulfanilamide

More information

H N 2. Decolorizing carbon O. O Acetanilide

H N 2. Decolorizing carbon O. O Acetanilide Experiment 1: Recrystallization of Acetanilide Reading Assignment Mohrig 2 4 (Glassware, Reagents, & Heating) & 14 15 (Melting Point & Recrystallization) The purification of organic compounds is a tedious,

More information

Kinetic vs. Thermodynamic Control

Kinetic vs. Thermodynamic Control Experiment: Kinetic vs. Thermodynamic Control of rganic Reactions Kinetic vs. Thermodynamic Control During your study of reactions this year you have examined many mechanisms. You have used these mechanisms

More information

Purification Of A Solid By Recrystallization AND Identification By Melting Point Determination

Purification Of A Solid By Recrystallization AND Identification By Melting Point Determination Purification Of A Solid By Recrystallization AND Identification By Melting Point Determination Refer back to your recrystallization and melting point experiments. In this experiment you must purify your

More information

Experiment 2. Recrystallization: The Purification of Crystalline Organic Compounds

Experiment 2. Recrystallization: The Purification of Crystalline Organic Compounds Experiment 2 Recrystallization: The Purification of Crystalline Organic Compounds The method selected for purifying a given organic compound depends on a number of factors such as the physical state of

More information

CH241 Experiment #1 (Weeks of September 11, 18, and 25, 2017)

CH241 Experiment #1 (Weeks of September 11, 18, and 25, 2017) CH241 Experiment #1 (Weeks of September 11, 18, and 25, 2017) SEPARATION AND RECOVERY OF ORGANIC COMPOUNDS, THIN LAYER CHROMATOGRAPHY, COLUMN CHROMATOGRAPHY, CRYSTALLIZATION, AND MELTING POINTS Overview

More information

AQA Chemistry A-level

AQA Chemistry A-level AQA Chemistry A-level Required Practical 10 Preparation of a pure organic solid, test of its purity, and preparation of a pure organic liquid Reflux Reflux: continuous boiling and condensing of a reaction

More information

Lab 2 Guide: Recrystallization (Aug 31 Sept 4)

Lab 2 Guide: Recrystallization (Aug 31 Sept 4) Lab 2 Guide: Recrystallization (Aug 31 Sept 4) How Recrystallization Works- The Basic Idea Recrystallization is a purification technique; it allows us to remove impurities in a sample. The idea is you

More information

ORGANIC CHEMISTRY I CHEMISTRY 261. MACEWAN UNIVERSITY Winter 2016

ORGANIC CHEMISTRY I CHEMISTRY 261. MACEWAN UNIVERSITY Winter 2016 ORGANIC CHEMISTRY I CHEMISTRY 261 MACEWAN UNIVERSITY Winter 2016 LABORATORY INFORMATION SAFETY a. PERSONAL PROTECTION b. LABORATORY ACTIVITIES USING CHEMICALS a. HANDLING/DISPENSING b. SPILLING c. DISPOSING

More information

EXPERIMENT 7A. Chemical Separation by Filtration and Recrystallization INTRODUCTION

EXPERIMENT 7A. Chemical Separation by Filtration and Recrystallization INTRODUCTION EXPERIMENT 7A Chemical Separation by Filtration and Recrystallization INTRODUCTION The solubilities of solid substances in different kinds of liquid solvents vary widely. Substances that we call salts

More information

John Congleton. Multistep Synthesis of Benzilic Acid:

John Congleton. Multistep Synthesis of Benzilic Acid: 1 Multistep Synthesis of Benzilic Acid: Introduction Synthetic organic chemist often use the product of one reaction as the reactant in subsequent reaction (multistep synthesis). This situation occurs

More information

The Recrystallization of Benzoic Acid and Determination of its Melting Point

The Recrystallization of Benzoic Acid and Determination of its Melting Point Doreen Foy Organic Chemistry 1 Laboratory The Recrystallization of Benzoic Acid and Determination of its Melting Point Hannah Loch 10/01/2012 Abstract The goal of the experiment was to obtain pure benzoic

More information

E24 PURIFICATION OF ORGANIC COMPOUNDS Distillation, recrystallisation, melting and boiling point determination

E24 PURIFICATION OF ORGANIC COMPOUNDS Distillation, recrystallisation, melting and boiling point determination E24 PURIFICATION OF ORGANIC COMPOUNDS Distillation, recrystallisation, melting and boiling point determination THE TASK To learn the main techniques of purifying organic compounds. THE SKILLS By the end

More information

Recrystallization II 23

Recrystallization II 23 Recrystallization II 23 Chem 355 Jasperse RECRYSTALLIZATIN-Week 2 1. Mixed Recrystallization of Acetanilide 2. Mixed Recrystallization of Dibenzylacetone 3. Recrystallization of an Unknown Background Review:

More information

Crystallization & Filtration

Crystallization & Filtration Crystallization & Filtration Purification of Salicyclic Acid and Sodium Chloride Separation processes Liquid-liquid extraction Adsorption Filtration Solid-liquid extraction (leaching) Elution chromatography

More information

Experiment 2: Preparation of the Artificial Sweetener Dulcin

Experiment 2: Preparation of the Artificial Sweetener Dulcin Experiment 2: Preparation of the Artificial Sweetener Dulcin Organic compounds known as sugars are carbohydrates that occur widely in nature. For example, sucrose (aka table sugar) is found in sugar can,

More information

Mon. Tues. Wed. Thurs. Fri. AM or PM B

Mon. Tues. Wed. Thurs. Fri. AM or PM B Name: (cf. Honesty Declaration Statement on page 20) Laboratory Day (circle) Lab Room Locker Lab. Session (circle) Lab. Section Mon. Tues. Wed. Thurs. Fri. AM or PM B Date experiment is performed MARK:

More information

COPPER CYCLE EXPERIMENT 3

COPPER CYCLE EXPERIMENT 3 COPPER CYCLE EXPERIMENT 3 INTRODUCTION One simple way to state the aim of chemistry is: The study of matter and its transformations. In this experiment, a copper sample will appear in five different forms

More information

The following are the completed but unbalanced equations. Each equation is numbered to match each step of the cycle:

The following are the completed but unbalanced equations. Each equation is numbered to match each step of the cycle: REACTIONS OF COPPER Copper will undergo many types of reactions. In this experiment you will observe a sequence of copper reactions. The sequence begins with copper metal and ends with copper metal, so

More information

Assistant Lecturer. Sahar Mohammed Shakir Assistant Lecturer. Abdul Hafeedh Hameed Assistant Lecturer. Ali Basim

Assistant Lecturer. Sahar Mohammed Shakir Assistant Lecturer. Abdul Hafeedh Hameed Assistant Lecturer. Ali Basim Assistant Lecturer Sahar Mohammed Shakir Assistant Lecturer Abdul Hafeedh Hameed Assistant Lecturer Ali Basim Solid organic cpd.s when isolated from organic reaction are impure; they are contaminated with

More information

CHMA2000 EXPT 2: Recrystallization

CHMA2000 EXPT 2: Recrystallization CHMA2000 EXPT 2: Recrystallization Experimental Objectives: At the end of this experiment you should be able to: 1. Perform a recrystallization 2. Determine the best solvent for the recrystallization of

More information

Chem2211L. Lab Report. Recrystallization

Chem2211L. Lab Report. Recrystallization Chem2211L Lab Report Recrystallization September 27, 2016 Experiment #3: Recrystallization Experiment Date: September 20, 2016 Lab Partners: Judienne Archer Tonja Bryant Alexis Dunn Objective: To separate

More information

crystallization melting individual molecules crystal lattice

crystallization melting individual molecules crystal lattice ... modular publisher: H. A. Neidig 3 TECH laboratory program in chemistry organic editor: Joe Jeffers 703. i8.. Purifying Acetanilide by Recrystallization prepared by Carl Wigal, Lebanon Valley College

More information

CONSERVATION OF MATTER AND CHEMICAL PROPERTIES

CONSERVATION OF MATTER AND CHEMICAL PROPERTIES 1 CONSERVATION OF MATTER AND CHEMICAL PROPERTIES I. OBJECTIVES AND BACKGROUND The object of this experiment is to demonstrate the conservation of matter- or more particularly, the conservation of "atoms"

More information

Copper Odyssey. Chemical Reactions of Copper

Copper Odyssey. Chemical Reactions of Copper Name Lab Partner(s) Copper Odyssey Chemical Reactions of Copper Date Period Elemental copper metal will be converted into copper (II) ion and then brought through a series of compound conversions until

More information

PREPARATION & ANALYSIS OF AN IRON COORDINATION COMPOUND PART A: PREPARATION OF AN IRON COORDINATION COMPOUND

PREPARATION & ANALYSIS OF AN IRON COORDINATION COMPOUND PART A: PREPARATION OF AN IRON COORDINATION COMPOUND Chemistry 112 PREPARATION & ANALYSIS OF AN IRON COORDINATION COMPOUND PART A: PREPARATION OF AN IRON COORDINATION COMPOUND A. INTRODUCTION In this experiment you will synthesize the iron coordination compound,

More information

Experiment 3: The Chromatography of Organic Compounds

Experiment 3: The Chromatography of Organic Compounds Experiment 3: The Chromatography of Organic Compounds INTRODUCTION Very often, in an organic synthesis, a reaction will proceed to produce multiple products or perhaps will only partially form the desired

More information

Experiment 2: The Chromatography of Organic Compounds

Experiment 2: The Chromatography of Organic Compounds Experiment 2: The Chromatography of Organic Compounds INTRODUCTION When performing an organic reaction, it is very common to observe the formation of other compounds in addition to your desired product;

More information

EXPERIMENT 1. AIM: To prepare benzilic acid from benzyl using Green approach.

EXPERIMENT 1. AIM: To prepare benzilic acid from benzyl using Green approach. EXPERIMENT 1 AIM: To prepare benzilic acid from benzyl using Green approach. Requirements: 100 ml conical flask, 200ml beakers, filter paper, oven,0.5 g benzil,20% alc KH, dil.sulfuric acid, benzene for

More information

The Chemical Importance of Purity Acquired Through Recrystalization and Analyzed by Melting Point

The Chemical Importance of Purity Acquired Through Recrystalization and Analyzed by Melting Point The Chemical Importance of Purity Acquired Through Recrystalization and Analyzed by Melting Point Codi Gail Hefner 1 and Brenton Matulka 1 1 University of Northwest Missouri State University Abstract:

More information

19. The preparation and purification of methyl-3-nitrobenzoate Student Sheet

19. The preparation and purification of methyl-3-nitrobenzoate Student Sheet 19. The preparation and purification of methyl-3-nitrobenzoate Student Sheet In this experiment you will learn or develop skills in preparative organic chemistry by making and purifying a sample of an

More information

Chapter 25 Separating Mixtures

Chapter 25 Separating Mixtures Chapter 25 Separating Mixtures A solution is formed when a solid dissolves in a liquid The solid is referred to as the solute. The liquid is referred to as the solvent. A dilute solution is one where there

More information

Chapter 4: Recrystallization & Melting Point

Chapter 4: Recrystallization & Melting Point Chapter 4: Recrystallization & Melting Point Recrystallization A purification technique for impure solid compounds A several-step process Can be on on a microscale or macroscale Melting Point Verifies

More information

University-level STEM Experiment: Recycling Cans to Alum The Ohio State University ENG Spring 2015 Taylor Ourada, Mary Scherer, Ramon

University-level STEM Experiment: Recycling Cans to Alum The Ohio State University ENG Spring 2015 Taylor Ourada, Mary Scherer, Ramon University-level STEM Experiment: Recycling Cans to Alum The Ohio State University ENG 5797.14 Spring 2015 Taylor Ourada, Mary Scherer, Ramon Weldemicael Table of Contents I. Introduction... 1 II. Learning

More information

UNKNOWN UNKNOWNS Requirements: classify your functional group

UNKNOWN UNKNOWNS Requirements: classify your functional group UNKNOWN UNKNOWNS Candidates: ALCOHOLS Table 70.2, p. 766, 767 CARBOXYLIC ACIDS Table 70.1, p 764,765 ALDEHYDES Table 70.3, p. 767, 768 AMINES Table 70.5, p. 769, 770 KETONES Tabl e 70.14, p. 776 Requirements:

More information

Changes for Organic Chemistry 2521 Labs

Changes for Organic Chemistry 2521 Labs Changes for Organic Chemistry 2521 Labs Chapter 3 Crystallization Part 1 (Starts on page 56) Test the solubility of three compounds with three solvents. There are four compounds to choose from: 1. Resorcinol

More information

RECRYSTALLIZATION, FILTRATION AND MELTING POINT

RECRYSTALLIZATION, FILTRATION AND MELTING POINT RECRYSTALLIZATIN, FILTRATIN AND MELTING PINT Recrystallization is one of the main purification methods for solid compounds on virtually any scale, from mg to kg to tons. From the experimental point of

More information

CH 112 Special Assignment #4 Chemistry to Dye for: Part A

CH 112 Special Assignment #4 Chemistry to Dye for: Part A CH 112 Special Assignment #4 Chemistry to Dye for: Part A PRE-LAB ASSIGNMENT: Make sure that you read this handout and bring the essentials to lab with you. Here are the pre-lab questions for this week.

More information

PHASE CHANGES. Time Temperature Observations. Name(s)

PHASE CHANGES. Time Temperature Observations. Name(s) 3 5 PHASE CHANGES PHASE CHANGES Name(s) The activities presented here focus on the energy changes that occur in substances undergoing a phase change. The first activity will take the most time to complete.

More information

Experiment: Acetylation of Ferrocene

Experiment: Acetylation of Ferrocene Experiment: Acetylation of Ferrocene Ferrocene is an unusual organometallic compound with a structure now understood to be a "sandwich" of an Fe 2+ cation between two parallel cyclopentadienyl anions.

More information

CHM Gravimetric Chloride Experiment (r7) 1/5

CHM Gravimetric Chloride Experiment (r7) 1/5 CHM 111 - Gravimetric Chloride Experiment (r7) 1/5 Purpose You will perform one of the basic types of quantitative analysis - the gravimetric analysis. You will be asked to determine the percentage of

More information

Experiment 3: Determination of an Empirical Formula

Experiment 3: Determination of an Empirical Formula Background Information The composition of a compound is defined by its chemical formula, which gives the number ratio of the different elements in the compound. For example, water has a fixed composition

More information

Chapter No. 2 EXPERIMENTAL TECHNIQUES IN CHEMISTRY LONG QUESTIONS Analytical Chemistry: The science of chemical characterization is called analytical chemistry. OR The branch of chemistry which deals with

More information

EXPERIMENT 5 Chemistry 110 COMPOSITION OF A MIXTURE

EXPERIMENT 5 Chemistry 110 COMPOSITION OF A MIXTURE EXPERIMENT 5 Chemistry 110 PURPOSE: The purpose of this experiment is to determine the percent composition of a mixture. COMPOSITION OF A MIXTURE Most matter is a mixture of many substances. For example,

More information

Chapter 8. Gravimetric Analysis

Chapter 8. Gravimetric Analysis Chapter 8 Gravimetric Analysis Gravimetric analysis is the use of weighing to determine the amount of a component in your sample. Gravimetric analysis, or gravimetry is normally performed either as a :

More information

hydroxynitrile ester dihaloalkane alkane alkene haloalkane alcohol amine nitrile ketone HCN + KCN Nucleophilic addition carboxylic acid

hydroxynitrile ester dihaloalkane alkane alkene haloalkane alcohol amine nitrile ketone HCN + KCN Nucleophilic addition carboxylic acid 6.2.5 Synthesis dihaloalkane poly(alkene) high pressure atalyst polymerization Br 2, l 2 Electrophilic addition alkene alkane 2, Nickel atalyst addition/reduction Br 2, l 2 UV light Free radical Substitution

More information

solvent diffusion dissolving soluble

solvent diffusion dissolving soluble What do we call it when a liquid changes into a solid? What do we call it when a liquid turns into a gas? What do we call it when a gas turns into a liquid? What do we call the solid that dissolves in

More information

Skills in Science. Lab equipment. (Always draw 2D) Drawings below are NOT to scale. Beaker - A general purpose container with a pouring lip.

Skills in Science. Lab equipment. (Always draw 2D) Drawings below are NOT to scale. Beaker - A general purpose container with a pouring lip. Skills in Science Safety: Do NOT enter or leave the lab without permission from a teacher. Keep the gaps between tables clear of stools and bags. Never run in the lab. Do not throw things around in the

More information

Cu (s) Cu 2+ (aq) Cu(OH) 2 (s) CuO (s) Cu 2+ (aq) Cu (s)

Cu (s) Cu 2+ (aq) Cu(OH) 2 (s) CuO (s) Cu 2+ (aq) Cu (s) Cycle of Copper Reactions Lab Exercise The following is a protocol for the multi-step transformation of copper metal based upon the following chemical transformations: Cu (s) Cu 2+ (aq) Cu(OH) 2 (s) CuO

More information

DETERMINATION of the EMPIRICAL FORMULA

DETERMINATION of the EMPIRICAL FORMULA DETERMINATION of the EMPIRICAL FORMULA One of the fundamental statements of the atomic theory is that elements combine in simple whole number ratios. This observation gives support to the theory of atoms,

More information

DOWNLOAD PDF CYCLE OF COPPER REACTIONS

DOWNLOAD PDF CYCLE OF COPPER REACTIONS Chapter 1 : Copperâ chlorine cycle - Wikipedia CYCLE OF COPPER REACTIONS. PURPOSE: The goal of the experiment is to observe a series of reactions involving copper that form a cycle and calculate the percent

More information

A Cycle of Copper Reactions

A Cycle of Copper Reactions EXPERIMENT A Cycle of Copper Reactions PURPOSE To demonstrate a series of copper reactions: starting with copper metal, oxidizing the metal to put it into solution and then, form a copper hydroxide, an

More information

Analysis of Calcium Carbonate Tablets

Analysis of Calcium Carbonate Tablets Experiment 9 Analysis of Calcium Carbonate Tablets Prepared by Ross S. Nord, Eastern Michigan University PURPOSE To perform a gravimetric exercise to determine weight percent of active ingredient in a

More information

CHEM 1215 LAB NOTES EXPT #2: PHYSICAL AND CHEMICAL CHANGES 1

CHEM 1215 LAB NOTES EXPT #2: PHYSICAL AND CHEMICAL CHANGES 1 CHEM 1215 LAB NOTES EXPT #2: PHYSICAL AND CHEMICAL CHANGES 1 TECHNIQUES: chemical and physical changes, reactions, observations READING: PHYSICAL AND CHEMICAL CHANGES e.g. Tro chapter 1 SAFETY: Safety

More information

Experiment: Preparation of Adipic Acid by Oxidative Cleavage of Cyclohexene

Experiment: Preparation of Adipic Acid by Oxidative Cleavage of Cyclohexene Experiment: Preparation of Adipic Acid by xidative Cleavage of Cyclohexene Under mild conditions, only the pi bond of the alkene is cleaved to form 1,2-diols or epoxides. Under more rigorous oxidation

More information

PERCENT Y IELD: COPPER T Ra NSFORMATIONS

PERCENT Y IELD: COPPER T Ra NSFORMATIONS Experiment 4 Name: 39 PERCENT Y IELD: COPPER T Ra NSFORMATIONS In this experiment, you will carry out and observe a reaction sequence where copper metal is the starting material that undergoes a series

More information

INTERACTIVE SCIENCE 1B

INTERACTIVE SCIENCE 1B INTERACTIVE SCIENCE 1B Workbook Solutions (Enrichment Edition) Chapter 5 THE WONDERFUL SOLVENT WATER Part A Sectional Exercise 5.1 Concept checking p.23 1. False 2. True 3. False 4. False 5. True Multiple

More information

Experimental techniques

Experimental techniques Unit 1 Experimental techniques In this unit you will come to understand the general principles behind various experimental techniques. Experimental investigation is a very important aspect of Physical

More information

To identify and classify various types of chemical reactions.

To identify and classify various types of chemical reactions. Cycle of Copper Reactions Minneapolis Community and Technical College v.11.17 Objectives: To observe and document copper s chemical changes in five different reactions and verify that copper is conserved

More information

CH361/361H Week 1 Lecture. Laboratory Notebook Keeping, Melting Point Determination, Recrystallization, & Yields. Identify unknown.

CH361/361H Week 1 Lecture. Laboratory Notebook Keeping, Melting Point Determination, Recrystallization, & Yields. Identify unknown. sodium salt of unknown aromatic carboxylic acid + soluble impurities + insoluble impurities total mass:? g insoluble impurities mass:? g colored dye(s) mass: ~ 20 mg dissolve in water, filter aq. sol n

More information

Pre-Lab Exercises Lab 8: Biochemistry

Pre-Lab Exercises Lab 8: Biochemistry Pre-Lab Exercises Lab 8: Biochemistry Name Date Section 1. List the 3 basic components of a DNA nucleotide, and draw a simple picture to show how they interact. 2. Consider the amine bases in DNA. List

More information

Teknik Bioseparasi. Dina Wahyu. Genap/ Maret 2014

Teknik Bioseparasi. Dina Wahyu. Genap/ Maret 2014 4. Teknik Bioseparasi Dina Wahyu Genap/ Maret 2014 Outline Chemical Reaction Engineering 1 2 3 4 5 6 7 Pendahuluan mempelajari ruang lingkup teknik bioseparasi dan teknik cel disruption Teknik Pemisahan

More information

Gravimetric Analysis: Determination of % Sulfur in Fertilizer

Gravimetric Analysis: Determination of % Sulfur in Fertilizer Gravimetric Analysis: Determination % Sulfur in Fertilizer This is another "real world" sample experiment in this case we will analyze a fertilizer sample for the sulfate content and express the result

More information

ELECTROPHORESIS OF SPOOLED DNA 1 An Introduction to Agarose (Horizontal) Electrophoresis

ELECTROPHORESIS OF SPOOLED DNA 1 An Introduction to Agarose (Horizontal) Electrophoresis ELECTROPHORESIS OF SPOOLED DNA 1 An Introduction to Agarose (Horizontal) Electrophoresis INTRODUCTION This laboratory will demonstrate the basics of horizontal electrophoresis and the theory behind the

More information

Melting Point 1. Figure 2. A close-up of the "business end" of the Mel-Temp apparatus. Figure 1. The mel-temp device.

Melting Point 1. Figure 2. A close-up of the business end of the Mel-Temp apparatus. Figure 1. The mel-temp device. Melting Point 1 The temperature at which a solid melts is known as the melting point (MP) of that substance. The melting point is a physical property of a solid and can be used to help identify a substance.

More information

EXPERIMENT 3: Identification of a Substance by Physical Properties

EXPERIMENT 3: Identification of a Substance by Physical Properties EXPERIMENT 3: Identification of a Substance by Physical Properties Materials: Hot plate Digital balance Capillary tubes (3) Thermometer Beakers (250 ml) Watch glass Graduated Cylinder (10 ml) Mel-Temp

More information

7. Determination of Melting Points

7. Determination of Melting Points 7. Determination of Melting Points This experiment consists of three parts. In the first part, you will determine the melting point range of three known compounds. This part is mostly for practice, to

More information

NEVER POUR ANYTHING EXCEPT WATER INTO THE SINKS ALL OTHER LIQUIDS AND SOLIDS ARE CONSIDERED HAZARDOUS WASTE.

NEVER POUR ANYTHING EXCEPT WATER INTO THE SINKS ALL OTHER LIQUIDS AND SOLIDS ARE CONSIDERED HAZARDOUS WASTE. THESE NOTES PROVIDE A SUMMARY OF POINTS THAT YOUR TA WILL COVER IN THE PRELAB TALK EACH WEEK. IT WILL BE HELPFUL TO HAVE THESE IN FRONT OF YOU AS THE PRELAB TALK IS PRESENTED. -----------------------------------------------------------------------------------

More information

4. Which of the following techniques is not used for chemical identification purposes?

4. Which of the following techniques is not used for chemical identification purposes? Version C. 1. A material which is a carcinogen causes: A) irritation to eyes and excess tearing B) inheritable genetic abnormalities C) visible destruction of human tissue D) cancer 2. What is the name

More information

Several complexes of Cu 2+, Ni 2+, and Co 2+ are formed and studied. The observations of color change that result from the addition of a ligand are

Several complexes of Cu 2+, Ni 2+, and Co 2+ are formed and studied. The observations of color change that result from the addition of a ligand are Overview Several complexes of Cu 2+, Ni 2+, and Co 2+ are formed and studied. The observations of color change that result from the addition of a ligand are used to understand the relative stability of

More information

COMBUSTION. A combustion reaction is the reaction of a substance with oxygen, usually with the rapid release of heat to produce a flame.

COMBUSTION. A combustion reaction is the reaction of a substance with oxygen, usually with the rapid release of heat to produce a flame. 1 COMBUSTION Copyright: Department of Chemistry, University of Idaho, Moscow, ID 2010. A combustion reaction is the reaction of a substance with oxygen, usually with the rapid release of heat to produce

More information

1001 Nitration of toluene to 4-nitrotoluene, 2-nitrotoluene and 2,4-dinitrotoluene

1001 Nitration of toluene to 4-nitrotoluene, 2-nitrotoluene and 2,4-dinitrotoluene 1001 Nitration of toluene to 4-nitrotoluene, 2-nitrotoluene and 2,4-dinitrotoluene CH 3 CH 3 CH 3 NO 2 CH 3 NO 2 HNO 3 /H 2 SO 4 + + + side products NO 2 NO 2 C 7 H 8 (92.1) HNO 3 (63.0) H 2 SO 4 (98.1)

More information

30th International Chemistry Olympiad

30th International Chemistry Olympiad 30th International Chemistry Olympiad Melbourne, Tuesday July 7, 1998 Laboratory Examination Exercises Official Version Attention! At all times while you are in the laboratory you must wear safety eye

More information

Determination of the Molar Mass of a Compound by Freezing Point Depression

Determination of the Molar Mass of a Compound by Freezing Point Depression Determination of the Molar Mass of a Compound by Freezing Point Depression Objective: The objective of this experiment is to determine the molar mass of an unknown solute by measuring the freezing point

More information

THE MOLECULAR WEIGHT OF A SOLUTE*

THE MOLECULAR WEIGHT OF A SOLUTE* Name Per THE MOLECULAR WEIGHT OF A SOLUTE* One of the most helpful things that can be known about an element or compound is its molecular weight (molecular mass, gram molecular mass, atomic mass, or gram

More information

Phase Diagrams Revised: 1/27/16 PHASE DIAGRAMS. Adapted from Bill Ponder, Collin College & MIT OpenCourseWare INTRODUCTION

Phase Diagrams Revised: 1/27/16 PHASE DIAGRAMS. Adapted from Bill Ponder, Collin College & MIT OpenCourseWare INTRODUCTION PHASE DIAGRAMS Adapted from Bill Ponder, Collin College & MIT OpenCourseWare INTRODUCTION A phase diagram is a graphical representation of the physical states of a substance as they relate to temperature

More information

Instructions of Using Eco-Goldex E Series Reagent in E-Waste Gold Stripping and Gold Recovery Procedures

Instructions of Using Eco-Goldex E Series Reagent in E-Waste Gold Stripping and Gold Recovery Procedures Instructions of Using Eco-Goldex E Series Reagent in E-Waste Gold Stripping and Gold Recovery Procedures Prepared by John Guo (P. Geo, Ph D) Eco-Goldex.com Tel: +1 438-825-5288 Email: john@eco-goldex.com

More information

Chem 355 Jasperse DISTILLATION

Chem 355 Jasperse DISTILLATION Chem 355 Jasperse DISTILLATION 1 Background Distillation is a widely used technique for purifying liquids. The basic distillation process involves heating a liquid such that liquid molecules vaporize.

More information

Year 7 Chemistry HW Questions

Year 7 Chemistry HW Questions Year 7 Chemistry HW Questions 37 minutes 56 marks Page 1 of 15 Q1. Molly used a ph sensor to test different liquids. She dipped the probe of the sensor into each liquid and recorded the ph value in a table.

More information

CLASSI ICATION OF MAT R AND HOMOGENEOUS AND HETEROGENEOUS MIXTURES

CLASSI ICATION OF MAT R AND HOMOGENEOUS AND HETEROGENEOUS MIXTURES Experiment 3 Name: CLASSI ICATION OF MAT R AND HOMOGENEOUS AND HETEROGENEOUS MIXTURES Classification of Matter A pure substance is matter with definite and constant composition with distinct chemical properties.

More information

Colligative Properties of Solutions: Freezing Point Depression

Colligative Properties of Solutions: Freezing Point Depression E1 Colligative Properties of Solutions: Freezing Point Depression PURPOSE The experiment to be performed is divided into three sections: (a) In part 1, the FP of the pure solvent, cyclohexane, is determined

More information

Archer G11 Partner: Judy Aug Gravimetric Analysis of a Metal Carbonate

Archer G11 Partner: Judy Aug Gravimetric Analysis of a Metal Carbonate Gravimetric Analysis of a Metal Carbonate Purpose The purpose of this lab is to identify the unknown carbonate. This can be done by finding the mass of the product carbonate and using stoichiometry on

More information

Preparation of copper(ii) sulfate from copper(ii) nitrate

Preparation of copper(ii) sulfate from copper(ii) nitrate Student s Name: Date: Background Preparation of copper(ii) sulfate from copper(ii) nitrate The purpose of this laboratory activity is to prepare copper(ii) sulfate from copper(ii) nitrate. This is done

More information

Evaluate long- range plans concerning resource use and by- product disposal for environmental, economic, and political impact

Evaluate long- range plans concerning resource use and by- product disposal for environmental, economic, and political impact Title: Author: Course: A Fluid State Of Mind Amanda Brewer Brookland High School Brookland Physical Science, Chemistry Duration: Three 45 minute class periods Grade Level: 9-12 Objective: The process of

More information

Experiment 21 - Solubility and Molecular Structure

Experiment 21 - Solubility and Molecular Structure Experiment 21 - Solubility and Molecular Structure Part 1 In this part of the experiment you will compare the solubilities of various substances in two very different solvents: water and cyclohexane. Recall

More information

Macroscale Synthesis of Triphenylmethanol via a Grignard Reaction and Reactions of Triphenylmethanol

Macroscale Synthesis of Triphenylmethanol via a Grignard Reaction and Reactions of Triphenylmethanol Macroscale Synthesis of Triphenylmethanol via a Grignard Reaction and Reactions of Triphenylmethanol Important: Everyone will do Chapter 38, Exp s 4, 5, and 7 and Chapter 33, Exp s 1, 2, and 8. We will

More information

Separating Mixtures WORKSHEETS

Separating Mixtures WORKSHEETS Attention Teachers KEEP IT SIMPLE SCIENCE Separating Year 7 Chemical Sciences WORKSHEETS KISS topic number Topic 03.7C KISS Worksheets are designed to consolidate students knowledge & understanding and/or

More information

GRAVIMETRIC DETERMINATION OF SULFATE IN AN UNKNOWN SOLUTION

GRAVIMETRIC DETERMINATION OF SULFATE IN AN UNKNOWN SOLUTION GRAVIMETRIC DETERMINATION OF SULFATE IN AN UNKNOWN SOLUTION AIM The main objective of this experiment is to determine the concentration of sulfate ion in an unknown solution by using gravimetry. INTRODUCTION

More information

Experiment: Preparation of Adipic Acid by Oxidative Cleavage

Experiment: Preparation of Adipic Acid by Oxidative Cleavage Experiment: Preparation of Adipic Acid by xidative Cleavage INTRDUCTIN The carbon-carbon double bond of an alkene is a site of relatively high electron density and therefore is susceptible to oxidation.

More information

Making Saline SOLUTION. Lab Number 2 Part 1

Making Saline SOLUTION. Lab Number 2 Part 1 Making Saline SOLUTION Lab Number 2 Part 1 Purpose The purpose of part 1 of this lab is to learn the proper way to make reagents that are needed for labs. Materials Need for the Lab are: Volumetric flasks

More information

CHM 152 Last Updated Jan Lab 3: Freezing-Point Depression

CHM 152 Last Updated Jan Lab 3: Freezing-Point Depression temperature, C CHM 152 Last Updated Jan. 2013 Lab 3: Freezing-Point Depression Introduction This lab will examine the effect a solute has on a liquid s freezing point and show how freezing-point depression

More information

EXPERIMENT 9 DEHYDRATION OF 2-METHYLCYCLOHEXANOL CH 3 H CH 3 OH H 3 PO 4 +

EXPERIMENT 9 DEHYDRATION OF 2-METHYLCYCLOHEXANOL CH 3 H CH 3 OH H 3 PO 4 + EXPERIMENT 9 DEHYDRATION OF 2-METHYLCYCLOHEXANOL CH 3 CH 3 H CH 3 OH H 3 PO 4 + + H 2 O In this experiment, a microscale distillation apparatus will be used to perform an acid-catalyzed dehydration reaction

More information

REVIEW. Basic Laboratory Techniques 1,2

REVIEW. Basic Laboratory Techniques 1,2 1 REVIEW Basic Laboratory Techniques 1,2 The techniques described in the following sections should have been covered in the prerequisite organic chemistry labs (Chem 261 or equivalent). You are therefore

More information

Experiment 1 MOLAR MASS DETERMINATION BY FREEZING POINT DEPRESSION

Experiment 1 MOLAR MASS DETERMINATION BY FREEZING POINT DEPRESSION 1 Experiment 1 MOLAR MASS DETERMINATION BY FREEZING POINT DEPRESSION Whenever a substance is dissolved in a solvent, the vapor pressure of the solvent is lowered. As a result of the decrease in the vapor

More information

Working with Hazardous Chemicals

Working with Hazardous Chemicals A Publication of Reliable Methods for the Preparation of Organic Compounds Working with Hazardous Chemicals The procedures in Organic Syntheses are intended for use only by persons with proper training

More information