Exp #1 Melting Point, Boiling Point, and Index of Refraction
|
|
- Kellie Carpenter
- 7 years ago
- Views:
Transcription
1 Exp #1 Melting Point, Boiling Point, and Index of Refraction Pre-Lab Complete items numbered 1-6 (omit number 3) as described in your lab syllabus. In addition to the known compounds, make sure your data table includes the appropriate physical properties for all the possible unknowns for each experiment (6 compounds for the melting point, 5 compounds for the boiling point and refractive index). Remember to write in pen in your lab notebook, and to turn in your carbon copies before you start the lab. Organic chemists determine the purity and characterization of intermediate and final products by simply measuring a few physical properties, including the melting point, boiling point, and index of refraction. Questions of the Day: How do the physical properties, melting point, boiling point, and index of refraction allow one to determine the purity of the product? What are the limitations of each technique? A. Melting Points Pure, crystalline solids have a characteristic melting point, which is expressed as the temperature range over which the solid melts to become a liquid. The transition between the solid and the liquid is so sharp for small samples of a pure substance that melting points can be measured to ±0.1 o C. Typically it is no more than ±1 o C. Melting points of pure compounds are recorded in handbooks, such as the Handbook of Chemistry and Physics (CRC) or the Merck Index. Alternatively, you can find this information on the Internet, for example at Measurements of the melting point of a solid can also provide information about the purity of the substance. Pure crystalline solids have a sharp melting point. They melt in a very narrow range (melting range) of temperatures, whereas mixtures melt with a broad temperature range. Mixtures also tend to melt at temperatures below the melting points of the pure solids. Many solid substances prepared in the organic laboratory are initially impure. These impurities affect the melting point of a substance. In a sample that contains a mixture of two compounds, each component usually depresses the melting point of the other, giving an observed melting point range that is lower and broader than the melting point of either component. A melting point composition diagram for two hypothetical solids, A and B, is shown below, as a graph of temperature versus composition. FIGURE 1
2 The eutectic point is the lowest temperature of the mixture and is determined by the equilibrium composition at which A and B melt in constant ratio. A sample whose composition is exactly that of the eutectic point will exhibit a sharp melting point at the eutectic temperature. This means a eutectic mixture can be mistaken for a pure compound since both have a sharp melting point. Because it is difficult to heat solids to temperatures above their melting points, and because pure solids tend to melt over a very small temperature range, melting points are often used to help identify compounds. We will use the Mel-Temp apparatus for measuring the melting point in our lab. The Mel-Temp apparatus uses closed-end capillary tubes. The sample is placed into a pre-designed slot and its melting behavior observed through a magnifying glass. Keep in mind that we have 5 Mel-Temps for the labs. Schedule your lab experiment to minimize waiting time. I. Melting points are best determined using a finely divided powder. Grind the sample using a mortar and pestle to ensure homogeneity. Fill a capillary tube to a height of no more than 2-3 mm with the packed urea. The sample can be packed tightly by dropping the capillary tube through glass tubing on a table top or the floor. Put the tube into the Mel-temp apparatus closed end down. Make sure that you can see the sample through the magnifying glass. Set the voltage to zero and turn on the Mel-temp. Turn the voltage to 4.5 and observe both the sample and temperature reading as you heat. (Never set the voltage at more than 7). Note (a) the temperature at which the column of urea first collapses or shows some liquid and (b) the temperature at which the sample is completely liquid. This is the melting range, which we call a melting point. Always report a melting range. The melting point is not accurate if the thermometer and the sample are not at the same temperature. For accuracy the sample should be heated through the melting range at a rate of 1 o C or less per minute. Turn off the apparatus and let it cool. If you did not get a good result for the melting point of urea, prepare a sample in a new capillary, and repeat the measurement. Capillaries cannot be reused. Put used capillaries in the glass waste container.
3 II. Work in groups of two for this part. Prepare a melting point diagram for a mixture of two compounds. We will use various prepared mixtures of urea and cinnamic acid. Record the melting point ranges of urea (from part I), pure cinnamic acid, a 1:1 urea:cinnamic acid mixture, a 4:1 urea:cinnamic acid mixture, and a 1:4 urea:cinnamic acid mixture. If you prefer to have more data points, feel free to make your own mixtures with various compositions. Plot your data in a melting point composition diagram similar to Figure 1. Make an accurate diagram using graph paper or a computer program and record your melting point ranges. III. You will be given a solid unknown. Your unknown is one of the following compounds: salicylic acid, benzoic acid, succinic acid, acetanilide, benzophenone, or napthalene. Samples of all of these compounds are available in the lab. In the procedure part of your Prelab explain how you plan to identify your unknown. Data and Observations Record the melting ranges obtained directly into your lab notebook. List any important observations you make while performing the experiment. For example, describe the appearance of a compound when it melts and any other visible changes occurring prior to, or during, the melting process, i.e. water vapor, gas bubbles, color changes, clarity of the liquid melt. Analysis Compare the literature melting points of all substances you have used and compare to the values you have determined experimentally. Comment on any discrepancies. Compare the melting point ranges of your pure urea and cinnamic acid with the mixture. Is it possible to estimate the eutectic point from your graph? Questions 1. How fast do you heat the sample in the Mel-temp when determining a melting point? 2. If you heat too fast, will your observed melting point be higher or lower than the true value? Explain. 3. What is meant by the term melting range? What happens at this range? 4. Why should you always use a new capillary tube with a sample of your compound when doing a second melting point determination? B. Refractive Indices The refractive index is a physical constant that, like the boiling point, can be used to characterize liquids. It is the ratio of the velocity of light in air to the velocity of light in the liquid. The angle of refraction is a function of temperature and the wavelength of light. Because the velocity of light in air is always greater than that through a liquid, the refractive index is a number greater than 1; for example, hexane n 20 D The superscript 20 indicates that the measurement was made at 20 o C, and the subscript D refers to the yellow D-line of a sodium vapor lamp, light with a wavelength of 589 nm.
4 The measurement is made with a refractometer using a few drops of liquid. Compensation is made within the instrument for the fact that white light and not sodium vapor light is used, but a temperature correction must be applied to the observed reading by adding for each degree above 20 o C. n 20 D = n t D (t 20 o C) equation 1 The refractive index can be determined to 1 part in 10,000, but because the value is quite sensitive to impurities, there is not always very good agreement with the literature with regard to the last figure. To master the technique of using the refractometer, you will measure the refractive indices of several known, pure liquids of your choice before measuring an unknown. For more information on the Abbe-3L refractometer (the instrument we have in the lab) and some video clips demonstrating its use, please go to Measure the refractive index for a known liquid compound. Place two or three drops of the sample on the open prism using a polyethylene pipette (to avoid scratching the prism face). Close the prism and turn on the light. Position the light for maximum brightness as seen through the eyepiece. If the refractometer is set to a nearly correct value, then a partially gray image will be seen. Turn the knob so that the line separating the dark and light areas is at the crosshairs. Sometimes the line separating the dark and light areas is fuzzy and colored. Turn the chromatic adjustment until the demarcation line is sharp and colorless. Then read the refractive index by pressing the button down to light up the scale in the field of vision. In your notebook record the temperature on the thermometer attached to the refractometer and make the appropriate temperature correction to the observed index of refraction using equation 1. Repeat this procedure with a second known compound. If the index of refraction is within experimental error for at least one compound, then proceed to the identification of an unknown sample as described in the boiling point procedure. C. Boiling Points The boiling points of pure organic liquids are, like the melting points, characteristic physical properties. The process of determining the boiling point is more complex than that for the melting point. It requires more material, and because it is less affected by impurities, it is not a good indication of purity. Like the melting point, the boiling point of a liquid is affected by the intermolecular forces that attract one molecule to another-ionic attraction, dipole-dipole interaction, hydrogen bonding, and van der Waals forces. A very clean liquid in a very clean vessel will superheat and not boil when subjected to a temperature above its boiling point. If boiling does occur under these conditions, it occurs with explosive violence. To avoid this problem boiling stones or a boiling stick is always added to liquids before heating them to boiling. 1. Practice your boiling point determination techniques, by placing about 0.3 ml of one of the liquids provided and a boiling stone in a reaction tube. Fit a distillation head (connecting adapter) on top of the reaction tube to ensure that the system is open to the atmosphere. REMEMBER TO NEVER HEAT A CLOSED SYSTEM! Using a thermometer adapter clamp a thermometer so that the bulb is just above the liquid, and then heat the liquid with a sand bath or a water bath (depending on the boiling point of your liquid, above 100 o C a sand bath, below 100 o C a water bath). Heating is regulated so that the boiling liquid refluxes (condenses the drips down) about 3
5 cm up the thermometer bulb in order to heat the mercury thoroughly. The boiling point is the highest temperature recorded by the thermometer and maintained over about a 1-minute time interval. True boiling is indicated by drops dripping from the thermometer and a constant temperature recorded on the thermometer. If the temperature is not constant, then you are probably not observing true boiling. 2. You will be given a liquid unknown. Your unknown is one of the following liquids: toluene, ethanol, cyclohexane, 1-butanol, or distilled water. All of the liquids will be available in the lab. In the procedure part of your lab, explain how you plan to identify your unknown using the boiling point and refractive index. Observation Record all your data directly in your lab notebook and compare experimental results with literature values. Comment on any discrepancies. Analysis Explain how you identified your liquid unknown using the boiling point and index of refraction. Comment on the technique of boiling point determination and refluxing and the use of the refractometer. Questions 1. What are the consequences of heating a closed system? 2. Which would you expect to have a higher boiling point, ethanol or dimethyl ether? Explain. 3. Answer the question of the day in your notebook.
Melting Point, Boiling Point, and Index of Refraction
Melting Point, Boiling Point, and Index of Refraction Melting points, boiling points, and index of refractions are easily measured physical properties of organic compounds useful in product characterization
More informationDetermination of Melting Points
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 make
More informationEXPERIMENT 1 (Organic Chemistry I)
EXPERIMENT 1 (Organic Chemistry I) Melting Point Determination Purpose a) Determine the purity of a substance using melting point as physical property b) Identify an unknown compound using its melting
More informationANALYSIS OF ASPIRIN INFRARED (IR) SPECTROSCOPY AND MELTING POINT DETERMINATION
Chem 306 Section (Circle) M Tu W Th Name Partners Date ANALYSIS OF ASPIRIN INFRARED (IR) SPECTROSCOPY AND MELTING POINT DETERMINATION Materials: prepared acetylsalicylic acid (aspirin), stockroom samples
More informationPhysical Properties of a Pure Substance, Water
Physical Properties of a Pure Substance, Water The chemical and physical properties of a substance characterize it as a unique substance, and the determination of these properties can often allow one to
More informationIn this experiment, we will use three properties to identify a liquid substance: solubility, density and boiling point..
Identification of a Substance by Physical Properties 2009 by David A. Katz. All rights reserved. Permission for academic use provided the original copyright is included Every substance has a unique set
More informationMelting Range 1 Experiment 2
Melting Range 1 Experiment 2 Background Information The melting range of a pure organic solid is the temperature range at which the solid is in equilibrium with its liquid. As heat is added to a solid,
More informationCHEM 2423 Recrystallization of Benzoic Acid EXPERIMENT 4 - Purification - Recrystallization of Benzoic acid
EXPERIMENT 4 - Purification - Recrystallization of Benzoic acid Purpose: a) To purify samples of organic compounds that are solids at room temperature b) To dissociate the impure sample in the minimum
More informationConsider next the behavior of a mixture of two liquid compounds. The example shown below is for a 1:1 mixture of cyclohexane (C) and toluene (T).
Distillation Distillation is a commonly used method for purifying liquids and separating mixtures of liquids into their individual components. Familiar examples include the distillation of crude fermentation
More informationDistillation Experiment
Distillation Experiment CHM226 Background The distillation process is a very important technique used to separate compounds based on their boiling points. A substance will boil only when the vapor pressure
More information5. Which temperature is equal to +20 K? 1) 253ºC 2) 293ºC 3) 253 C 4) 293 C
1. The average kinetic energy of water molecules increases when 1) H 2 O(s) changes to H 2 O( ) at 0ºC 3) H 2 O( ) at 10ºC changes to H 2 O( ) at 20ºC 2) H 2 O( ) changes to H 2 O(s) at 0ºC 4) H 2 O( )
More information1. The Determination of Boiling Point
1. The Determination of Boiling Point Objective In this experiment, you will first check your thermometer for errors by determining the temperature of two stable equilibrium systems. You will then use
More informationChemistry 212 VAPOR PRESSURE OF WATER LEARNING OBJECTIVES
Chemistry 212 VAPOR PRESSURE OF WATER LEARNING OBJECTIVES The learning objectives of this experiment are to explore the relationship between the temperature and vapor pressure of water. determine the molar
More informationChemistry 112 Laboratory Experiment 6: The Reaction of Aluminum and Zinc with Hydrochloric Acid
Chemistry 112 Laboratory Experiment 6: The Reaction of Aluminum and Zinc with Hydrochloric Acid Introduction Many metals react with acids to form hydrogen gas. In this experiment, you will use the reactions
More informationExperiment 5: Column Chromatography
Experiment 5: Column Chromatography Separation of Ferrocene & Acetylferrocene by Column Chromatography Reading: Mohrig, Hammond & Schatz Ch. 18 pgs 235-253 watch the technique video on the course website!
More informationPre-Lab Notebook Content: Your notebook should include the title, date, purpose, procedure; data tables.
Determination of Molar Mass by Freezing Point Depression M. Burkart & M. Kim Experimental Notes: Students work in pairs. Safety: Goggles and closed shoes must be worn. Dispose of all chemical in the plastic
More informationDetermination of Molar Mass by Freezing-Point Depression
DETERMINATION OF MOLAR MASS BY FREEZING-POINT DEPRESSION 141 Determination of Molar Mass by Freezing-Point Depression OBJECTIVES: Gain familiarity with colligative properties of nonelectrolyte solutions
More informationReview - After School Matter Name: Review - After School Matter Tuesday, April 29, 2008
Name: Review - After School Matter Tuesday, April 29, 2008 1. Figure 1 The graph represents the relationship between temperature and time as heat was added uniformly to a substance starting at a solid
More informationPhase Diagram of tert-butyl Alcohol
Phase Diagram of tert-butyl Alcohol Bill Ponder Department of Chemistry Collin College Phase diagrams are plots illustrating the relationship of temperature and pressure relative to the phase (or state
More informationChem 112 Intermolecular Forces Chang From the book (10, 12, 14, 16, 18, 20,84,92,94,102,104, 108, 112, 114, 118 and 134)
Chem 112 Intermolecular Forces Chang From the book (10, 12, 14, 16, 18, 20,84,92,94,102,104, 108, 112, 114, 118 and 134) 1. Helium atoms do not combine to form He 2 molecules, What is the strongest attractive
More informationEXPERIMENT 9 (Organic Chemistry II) Pahlavan - Cherif Synthesis of Aspirin - Esterification
EXPERIMENT 9 (rganic hemistry II) Pahlavan - herif Materials Hot plate 125-mL Erlenmeyer flask Melting point capillaries Melting point apparatus Büchner funnel 400-mL beaker Stirring rod hemicals Salicylic
More informationChapter 12 - Liquids and Solids
Chapter 12 - Liquids and Solids 12-1 Liquids I. Properties of Liquids and the Kinetic Molecular Theory A. Fluids 1. Substances that can flow and therefore take the shape of their container B. Relative
More informationExperiment 2: Recrystallization & Melting Point
Experiment 2: Recrystallization & Melting Point Part A: Choosing a Solvent Part B: Purification of Phenacetin Reading: Mohrig, Hammond & Schatz Ch. 15 pgs 183-197 Ch. 10 pgs 104-113 Ch. 14 pgs 174-182
More informationTaking Apart the Pieces
Lab 4 Taking Apart the Pieces How does starting your morning out right relate to relief from a headache? I t is a lazy Saturday morning and you ve just awakened to your favorite cereal Morning Trails and
More informationESSAY. Write your answer in the space provided or on a separate sheet of paper.
Test 1 General Chemistry CH116 Summer, 2012 University of Massachusetts, Boston Name ESSAY. Write your answer in the space provided or on a separate sheet of paper. 1) Sodium hydride reacts with excess
More informationMOLECULAR WEIGHT BY BOILING POINT ELEVATION
MOLECULAR WEIGHT BY BOILING POINT ELEVATION BACKGROUND This experiment demonstrates the use of colligative properties. The goal is to measure the molecular weight of a non-volatile solute by determining
More informationGreen Principles Atom Economy Solventless Reactions Catalysis
Lab 5: The Aldol Reaction Solventless vs Traditional Reactions: (Melting Point Study & Recrystallization) (adapted from Doxsee, K.M. and Hutchison, J.E., Green Organic Chemistry and John Thompson; Lane
More informationWarm-Up 9/9. 1. Define the term matter. 2. Name something in this room that is not matter.
Warm-Up 9/9 1. Define the term matter. 2. Name something in this room that is not matter. Warm-Up 9/16 1. List the three most important rules of lab safety. 2. Would you classify jello as a solid or a
More information15. Liquid-in-Glass Thermometry
123 15. Liquid-in-Glass Thermometry Even though the liquid-in-glass thermometer is used much less frequently today than formerly, it is still a very commonly used device. Although it is normally an instrument
More informationORGANIC LABORATORY TECHNIQUES 10 10.1. NEVER distill the distillation flask to dryness as there is a risk of explosion and fire.
ORGANIC LABORATORY TECHNIQUES 10 10.1 DISTILLATION NEVER distill the distillation flask to dryness as there is a risk of explosion and fire. The most common methods of distillation are simple distillation
More informationSOLUBILITY OF A SALT IN WATER AT VARIOUS TEMPERATURES LAB
SOLUBILITY OF A SALT IN WATER AT VARIOUS TEMPERATURES LAB Purpose: Most ionic compounds are considered by chemists to be salts and many of these are water soluble. In this lab, you will determine the solubility,
More informationA Beer s Law Experiment
A Beer s Law Experiment Introduction There are many ways to determine concentrations of a substance in solution. So far, the only experiences you may have are acid-base titrations or possibly determining
More informationName Lab #3: Solubility of Organic Compounds Objectives: Introduction: soluble insoluble partially soluble miscible immiscible
Lab #3: Solubility of rganic Compounds bjectives: - Understanding the relative solubility of organic compounds in various solvents. - Exploration of the effect of polar groups on a nonpolar hydrocarbon
More informationDetermination of Molar Mass by Boiling Point Elevation of Urea Solution
Determination of Molar Mass by Boiling Point Elevation of Urea Solution CHRISTIAN E. MADU, PhD AND BASSAM ATTILI, PhD COLLIN COLLEGE CHEMISTRY DEPARTMENT Purpose of the Experiment Determine the boiling
More informationPURIFICATION TECHNIQUES
DETERMINACIÓN DE ESTRUCTURAS ORGÁNICAS (ORGANIC SPECTROSCOPY) PURIFICATION TECHNIQUES Hermenegildo García Gómez Departamento de Química Instituto de Tecnología Química Universidad Politécnica de Valencia
More informationDistillation vaporization sublimation. vapor pressure normal boiling point.
Distillation Distillation is an important commercial process that is used in the purification of a large variety of materials. However, before we begin a discussion of distillation, it would probably be
More informationPhysical and Chemical Properties and Changes
Physical and Chemical Properties and Changes An understanding of material things requires an understanding of the physical and chemical characteristics of matter. A few planned experiments can help you
More informationBomb Calorimetry. Electrical leads. Stirrer
Bomb Calorimetry Stirrer Electrical leads Oxygen inlet valve Bomb Fuse Calorimeter Outer jacket Not shown: heating and cooling system for outer jacket, and controls that keep the outer jacket at the same
More informationFractional Distillation and Gas Chromatography
Fractional Distillation and Gas Chromatography Background Distillation The previous lab used distillation to separate a mixture of hexane and toluene based on a difference in boiling points. Hexane boils
More informationStates of Matter and the Kinetic Molecular Theory - Gr10 [CAPS]
OpenStax-CNX module: m38210 1 States of Matter and the Kinetic Molecular Theory - Gr10 [CAPS] Free High School Science Texts Project This work is produced by OpenStax-CNX and licensed under the Creative
More informationLaboratory Exercise: Calibration of a Thermometer
CHEM 109 Introduction themistry Revision 3.1 Laboratory Exercise: Calibration of a Thermometer In this exercise we will calibrate a stem-type thermometer and then use it to correctly measure the Air temperature
More informationPartner: Jack 17 November 2011. Determination of the Molar Mass of Volatile Liquids
Partner: Jack 17 November 2011 Determination of the Molar Mass of Volatile Liquids Purpose: The purpose of this experiment is to determine the molar mass of three volatile liquids. The liquid is vaporized
More informationBiology 3A Laboratory: Enzyme Function
Biology 3A Laboratory: Enzyme Function Objectives To be able to list the general characteristics of enzymes. To study the effects of enzymes on the rate of chemical reactions. To demonstrate the effect
More informationThe Synthesis of trans-dichlorobis(ethylenediamine)cobalt(iii) Chloride
CHEM 122L General Chemistry Laboratory Revision 2.0 The Synthesis of trans-dichlorobis(ethylenediamine)cobalt(iii) Chloride To learn about Coordination Compounds and Complex Ions. To learn about Isomerism.
More informationTo measure the solubility of a salt in water over a range of temperatures and to construct a graph representing the salt solubility.
THE SOLUBILITY OF A SALT IN WATER AT VARIOUS TEMPERATURES 2007, 1995, 1991 by David A. Katz. All rights reserved. Permission for academic use provided the original copyright is included. OBJECTIVE To measure
More informationName Date Class STATES OF MATTER. SECTION 13.1 THE NATURE OF GASES (pages 385 389)
13 STATES OF MATTER SECTION 13.1 THE NATURE OF GASES (pages 385 389) This section introduces the kinetic theory and describes how it applies to gases. It defines gas pressure and explains how temperature
More informationHands-On Labs SM-1 Lab Manual
EXPERIMENT 4: Separation of a Mixture of Solids Read the entire experiment and organize time, materials, and work space before beginning. Remember to review the safety sections and wear goggles when appropriate.
More informationMolar Mass of Butane
Cautions Butane is toxic and flammable. No OPEN Flames should be used in this experiment. Purpose The purpose of this experiment is to determine the molar mass of butane using Dalton s Law of Partial Pressures
More informationSeparation of Amino Acids by Paper Chromatography
Separation of Amino Acids by Paper Chromatography Chromatography is a common technique for separating chemical substances. The prefix chroma, which suggests color, comes from the fact that some of the
More informationMelting Point Determination Application Note #1
Melting Point Determination Application Note #1 Introduction A few basic guidelines must be carefully followed to avoid errors during melting point determinations with OptiMelt. The way in which the sample
More informationName Class Date. In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question.
Assessment Chapter Test A Chapter: States of Matter In the space provided, write the letter of the term or phrase that best completes each statement or best answers each question. 1. The kinetic-molecular
More informationCalorimetry: Heat of Vaporization
Calorimetry: Heat of Vaporization OBJECTIVES INTRODUCTION - Learn what is meant by the heat of vaporization of a liquid or solid. - Discuss the connection between heat of vaporization and intermolecular
More informationApparatus error for each piece of equipment = 100 x margin of error quantity measured
1) Error Analysis Apparatus Errors (uncertainty) Every time you make a measurement with a piece of apparatus, there is a small margin of error (i.e. uncertainty) in that measurement due to the apparatus
More informationRECITATION NOTES FOR EXPERIMENT # 5 A&B THIN LAYER CHROMATOGRAPHY
RECITATION NOTES FOR EXPERIMENT # 5 A&B THIN LAYER CHROMATOGRAPHY Have your lab textbook available for quick reference to specific pages, indicated in red. BASIC PRINCIPLES OF CHROMATOGRAPHY Chromatography
More informationVAPOR PRESSURE AS A FUNCTION OF TEMPERATURE. This laboratory covers material presented in section 11.8 of the 9 th Ed. of the Chang text.
VAPOR PRESSURE AS A FUNCTION OF TEMPERATURE Objectives: (1) Observe and measure the change in the vapor pressure (dependent variable) as a function of temperature (independent variable). (2) Analyze the
More informationEnzyme Pre-Lab. Using the Enzyme worksheet and Enzyme lab handout answer the Pre-Lab questions the pre-lab must be complete before beginning the lab.
Enzyme Pre-Lab Using the Enzyme worksheet and Enzyme lab handout answer the Pre-Lab questions the pre-lab must be complete before beginning the lab. Background: In this investigation, you will study several
More informationThe Determination of an Equilibrium Constant
The Determination of an Equilibrium Constant Computer 10 Chemical reactions occur to reach a state of equilibrium. The equilibrium state can be characterized by quantitatively defining its equilibrium
More informationAbsorbance Spectrophotometry: Analysis of FD&C Red Food Dye #40
Absorbance Spectrophotometry: Analysis of FD&C Red Food Dye #40 Note: there is a second document that goes with this one! 2046 - Absorbance Spectrophotometry - Calibration Curve Procedure. The second document
More informationDetermining the Quantity of Iron in a Vitamin Tablet. Evaluation copy
Determining the Quantity of Iron in a Vitamin Tablet Computer 34 As biochemical research becomes more sophisticated, we are learning more about the role of metallic elements in the human body. For example,
More informationRecrystallization 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 informationEXPERIMENT 1 - Determination of the purity and identity of organic compounds by melting point and/or analytical thin layer chromatography
EXPERIMENT 1 - Determination of the purity and identity of organic compounds by melting point and/or analytical thin layer chromatography PART A Melting points and mixed melting points. As discussed in
More informationPaper Chromatography: Separation and Identification of Five Metal Cations
Paper Chromatography: Separation and Identification of Five Metal Cations Objectives Known and unknown solutions of the metal ions Ag +, Fe 3+, Co 2+, Cu 2+ and Hg 2+ will be analyzed using paper chromatography.
More informationexperiment5 Understanding and applying the concept of limiting reagents. Learning how to perform a vacuum filtration.
81 experiment5 LECTURE AND LAB SKILLS EMPHASIZED Synthesizing an organic substance. Understanding and applying the concept of limiting reagents. Determining percent yield. Learning how to perform a vacuum
More informationChemical Changes. Measuring a Chemical Reaction. Name(s)
Chemical Changes Name(s) In the particle model of matter, individual atoms can be bound tightly to other atoms to form molecules. For example, water molecules are made up of two hydrogen atoms bound to
More informationReaction of Magnesium with Hydrochloric Acid (Gas Laws) Chemicals Needed:
Reaction of Magnesium with Hydrochloric Acid (Gas Laws) Your Name: Date: Partner(s) Names: Objectives: React magnesium metal with hydrochloric acid, collecting the hydrogen over water. Calculate the grams
More informationThin Layer Chromatography.
Thin Layer Chromatography. Thin layer chromatography, or TLC, is a method for analyzing mixtures by separating the compounds in the mixture. TLC can be used to help determine the number of components in
More information7. Gases, Liquids, and Solids 7.1 Kinetic Molecular Theory of Matter
7. Gases, Liquids, and Solids 7.1 Kinetic Molecular Theory of Matter Kinetic Molecular Theory of Matter The Kinetic Molecular Theory of Matter is a concept that basically states that matter is composed
More informationDetermining Equivalent Weight by Copper Electrolysis
Purpose The purpose of this experiment is to determine the equivalent mass of copper based on change in the mass of a copper electrode and the volume of hydrogen gas generated during an electrolysis reaction.
More informationTest 5 Review questions. 1. As ice cools from 273 K to 263 K, the average kinetic energy of its molecules will
Name: Thursday, December 13, 2007 Test 5 Review questions 1. As ice cools from 273 K to 263 K, the average kinetic energy of its molecules will 1. decrease 2. increase 3. remain the same 2. The graph below
More informationExperiment 12E LIQUID-VAPOR EQUILIBRIUM OF WATER 1
Experiment 12E LIQUID-VAPOR EQUILIBRIUM OF WATER 1 FV 6/26/13 MATERIALS: PURPOSE: 1000 ml tall-form beaker, 10 ml graduated cylinder, -10 to 110 o C thermometer, thermometer clamp, plastic pipet, long
More informationMixtures and Pure Substances
Unit 2 Mixtures and Pure Substances Matter can be classified into two groups: mixtures and pure substances. Mixtures are the most common form of matter and consist of mixtures of pure substances. They
More informationEXPERIMENT 15: Ideal Gas Law: Molecular Weight of a Vapor
EXPERIMENT 15: Ideal Gas Law: Molecular Weight of a Vapor Purpose: In this experiment you will use the ideal gas law to calculate the molecular weight of a volatile liquid compound by measuring the mass,
More informationPure Solid Compounds: Molecules held together in rigid formations by intermolecular forces.
Recrystallization: Purification of Solid Compounds Pure Solid Compounds: Molecules held together in rigid formations by intermolecular forces. Types of Intermolecular Forces? 1. Van der Waal s forces London
More informationExperiment 446.1 SURFACE TENSION OF LIQUIDS. Experiment 1, page 1 Version of June 17, 2016
Experiment 1, page 1 Version of June 17, 2016 Experiment 446.1 SURFACE TENSION OF LIQUIDS Theory To create a surface requires work that changes the Gibbs energy, G, of a thermodynamic system. dg = SdT
More informationExperiment #10: Liquids, Liquid Mixtures and Solutions
Experiment #10: Liquids, Liquid Mixtures and Solutions Objectives: This experiment is a broad survey of the physical properties of liquids. We will investigate solvent/solute mixtures. We will study and
More informationPhysical Chemistry Laboratory I CHEM 445 Experiment 6 Vapor Pressure of a Pure Liquid (Revised, 01/09/06)
1 Physical Chemistry Laboratory I CHEM 445 Experiment 6 Vapor Pressure of a Pure Liquid (Revised, 01/09/06) The vapor pressure of a pure liquid is an intensive property of the compound. That is, the vapor
More informationSUPPLEMENTARY MATERIAL
SUPPLEMENTARY MATERIAL (Student Instructions) Determination of the Formula of a Hydrate A Greener Approach Objectives To experimentally determine the formula of a hydrate salt. To learn to think in terms
More informationvap H = RT 1T 2 = 30.850 kj mol 1 100 kpa = 341 K
Thermodynamics: Examples for chapter 6. 1. The boiling point of hexane at 1 atm is 68.7 C. What is the boiling point at 1 bar? The vapor pressure of hexane at 49.6 C is 53.32 kpa. Assume that the vapor
More informationCHEMICAL DETERMINATION OF EVERYDAY HOUSEHOLD CHEMICALS
CHEMICAL DETERMINATION OF EVERYDAY HOUSEHOLD CHEMICALS Purpose: It is important for chemists to be able to determine the composition of unknown chemicals. This can often be done by way of chemical tests.
More informationMINERAL OIL (MEDIUM VISCOSITY)
MINERAL OIL (MEDIUM VISCOSITY) Prepared at the 76 th JECFA, published in FAO JECFA Monographs 13 (2012), superseding specifications for Mineral oil (Medium and low viscosity), class I prepared at the 59th
More informationLab: Properties of Polar and Nonpolar Substances
Lab: Properties of Polar and Nonpolar Substances Purpose: To explain the interactions of matter in relation to polarity. Stations 1 and 2 - il and water do not mix As a metaphor, oil and water are often
More informationExperiment 1: Colligative Properties
Experiment 1: Colligative Properties 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
More informationExp 13 Volumetric Analysis: Acid-Base titration
Exp 13 Volumetric Analysis: Acid-Base titration Exp. 13 video (time: 47:17 minutes) Titration - is the measurement of the volume of a standard solution required to completely react with a measured volume
More informationThe Molar Mass of a Gas
The Molar Mass of a Gas Goals The purpose of this experiment is to determine the number of grams per mole of a gas by measuring the pressure, volume, temperature, and mass of a sample. Terms to Know Molar
More informationTHE ACTIVITY OF LACTASE
THE ACTIVITY OF LACTASE Lab VIS-8 From Juniata College Science in Motion Enzymes are protein molecules which act to catalyze the chemical reactions in living things. These chemical reactions make up the
More informationClassification of Chemical Substances
Classification of Chemical Substances INTRODUCTION: Depending on the kind of bonding present in a chemical substance, the substance may be called ionic, molecular or metallic. In a solid ionic compound
More informationNuclear Structure. particle relative charge relative mass proton +1 1 atomic mass unit neutron 0 1 atomic mass unit electron -1 negligible mass
Protons, neutrons and electrons Nuclear Structure particle relative charge relative mass proton 1 1 atomic mass unit neutron 0 1 atomic mass unit electron -1 negligible mass Protons and neutrons make up
More informationDigiBlock Sample Preparation System APPLICATION NOTES LABTECH INC. Your Lab, Our Tech
E D 3 6 & E H D 3 6 DigiBlock Sample Preparation System APPLICATION NOTES LABTECH INC. Your Lab, Our Tech CONTENT 1 ENVIRONMENTAL... 5 1.1 SOIL... 5 1.2 WASTE WATER... 6 2 FOOD... 7 2.1 RICE... 7 2.2
More informationSynthesis of Isopentyl Acetate
Experiment 8 Synthesis of Isopentyl Acetate Objectives To prepare isopentyl acetate from isopentyl alcohol and acetic acid by the Fischer esterification reaction. Introduction Esters are derivatives of
More informationInvestigation M3: Separating Mixtures into Component Parts
Investigation M3: Separating Mixtures into Component Parts Goals: Use various methods to separate mixtures, make inferences from temperature/time graphs, and identify substances. 81 Activity M3.3: What
More informationExam 4 Practice Problems false false
Exam 4 Practice Problems 1 1. Which of the following statements is false? a. Condensed states have much higher densities than gases. b. Molecules are very far apart in gases and closer together in liquids
More information# 12 Condensation Polymerization: Preparation of Two Types of Polyesters
# 12 Condensation Polymerization: Preparation of Two Types of Polyesters Submitted by: Arturo Contreras, Visiting Scholar, Center for Chemical Education, Miami University, Middletown, OH; 1996 1997. I.
More informationIsolation of Caffeine from Tea
Isolation of Caffeine from Tea Introduction A number of interesting, biologically active compounds have been isolated from plants. Isolating some of these natural products, as they are called, can require
More informationDetermination of Aspirin using Back Titration
Determination of Aspirin using Back Titration This experiment is designed to illustrate techniques used in a typical indirect or back titration. You will use the NaH you standardized last week to back
More information1 Introduction The Scientific Method (1 of 20) 1 Introduction Observations and Measurements Qualitative, Quantitative, Inferences (2 of 20)
The Scientific Method (1 of 20) This is an attempt to state how scientists do science. It is necessarily artificial. Here are MY five steps: Make observations the leaves on my plant are turning yellow
More informationEXAMPLE EXERCISE 4.1 Change of Physical State
EXAMPLE EXERCISE 4.1 Change of Physical State State the term that applies to each of the following changes of physical state: (a) Snow changes from a solid to a liquid. (b) Gasoline changes from a liquid
More informationTo calculate the value of the boiling point constant for water. To use colligative properties to determine the molecular weight of a substance.
Colligative Properties of Solutions: A Study of Boiling Point Elevation Amina El-Ashmawy, Collin County Community College (With contributions by Timm Pschigoda, St. Joseph High School, St. Joseph, MI)
More information6. 2. Unit 6: Physical chemistry of spectroscopy, surfaces and chemical and phase equilibria
6. 2 Phase equilibria Many industrial processes involve several phases in equilibrium gases, liquids, solids and even different crystalline forms of the solid state. Predicting the number of phases present
More information7. 1.00 atm = 760 torr = 760 mm Hg = 101.325 kpa = 14.70 psi. = 0.446 atm. = 0.993 atm. = 107 kpa 760 torr 1 atm 760 mm Hg = 790.
CHATER 3. The atmosphere is a homogeneous mixture (a solution) of gases.. Solids and liquids have essentially fixed volumes and are not able to be compressed easily. have volumes that depend on their conditions,
More informationCompounds vs mixtures. Physics and Chemistry IES Jaume Salvador i Pedrol February 2009
Compounds vs mixtures Physics and Chemistry IES Jaume Salvador i Pedrol February 2009 Compounds Remember that a compound is a substance made up from two or more elements, chemically joined together. This
More information