Spectroscopic Determination of the Concentration of Manganese
|
|
- Elijah Merritt
- 7 years ago
- Views:
Transcription
1 Spectroscopic Determination of the Concentration of Manganese Objectives The objective of this laboratory is to use absorption spectroscopy to determine the amount of Mn 2+ in an aqueous solution. Background Manganese Manganese is a steel-gray, lustrous metal that resembles iron, except that it is harder, more brittle, and more resistant to high temperatures. It tarnishes slowly in air and is not particularly reactive to nonmetals except at elevated temperatures. Manganese makes up about 850 ppm (0.085%) of the Earth s crust, making it the 12th most abundant element there; among the heavy metals, only iron is more common. It is used in a variety of industrial applications, including steel production, corrosion-resistant aluminum alloys, alkaline batteries, and as a pigment for the coloring of ceramics and glass. Manganese occurs in many oxidation states, including +2, +3, +4, +6 and +7. The +2 cation is the most stable oxidation state for manganese and has a pale pink color in aqueous solution. The +7 cation is most often found in compounds of the intensely purple-violet permanganate anion, MnO 4. Manganese is a required trace mineral for all known living organisms. A normal human diet typically includes 2 9 mg of manganese per day. The +2 cation is the state used in living organisms for essential functions; other states are toxic for the human body. While ingesting too little manganese is not known to cause adverse effects, too much can lead to serious health problems, such as impaired motor skills and cognitive disorders. Absorption Spectroscopy Spectroscopy is one of the most powerful analytical techniques in modern science. In this experiment we will determine the quantity of manganese in an aqueous solution using visible Absorption Spectroscopy. When visible light is directed at a colored species in solution, the species will absorb some of that light at a given wavelength. The higher the concentration of the colored species, the more intense the solution color, and the more light it will absorb. In other words, the absorption of light (A) is directly proportional to the concentration of colored species in the solution. This relationship is known as Beer s Law, and may be expressed as: A = ELC where E is the molar extinction coefficient (a constant that depends characteristics of the species analyzed and the wavelength used for analysis), L is the path length (the distance traveled by light through the sample), and C is the concentration of the solution in mg/ml. In most cases L is a constant (1.0 cm in our experiment) and can therefore be factored into E. Spectroscopic Determination of Manganese Concentration Page 1 of 7
2 This means that Beer s Law can essentially be simplified as: A = EC Note that this is the equation of a line where the y-intercept is through the origin (b = 0): y = mx With this in mind, in this lab you will prepare a series of solutions with known manganese concentrations and measure their light absorbance. According to Beer s Law, a plot of Absorbance as a function of solution concentration should display a linear relationship; a best-fit trendline can be applied and the line equation determined. This line equation is a called a calibration equation, and the plot a calibration curve. The calibration equation may then be used to determine the manganese concentration in an unknown solution by measuring its absorbance under the same conditions. UV-Visible Spectrophotometer A UV-Visible spectrophotometer is the device used to measure how much light is absorbed by a colored species in solution at a specific wavelength. A schematic diagram of a typical spectrophotometer is shown below. incident light Io transmitted light It Sample detector lamp Rotatable prism or grating monochrometer Computer Light Absorbed, A = log(i o /I t ) A Wavelength Experimental Considerations One complication in this lab is that the aqueous solutions supplied for analysis contain manganese as Mn 2+ cations, which are a very pale pink color practically colorless. Visible absorption spectroscopy works best for solutions of deeply colored species. Fortunately, the Mn 2+ cations are easily oxidized in acidic solution to form permanganate anions, MnO 4, an intensely purple-violet species. The very intense color means that the spectrophotometric analysis can be very sensitive because the light absorption will be relatively large, even with small amounts of manganese in the sample. Potassium periodate, KIO 4, will be used to oxidize Mn 2+ to the purple-violet MnO 4 ion, according to the following balanced equation: 2 Mn 2+ (aq) + 5 KIO 4 (aq) + 3 H 2 O (l) 2 MnO 4 (aq) + 5 KIO 3 (aq) + 6 H + (aq) pale pink/colorless intense purple-violet Spectroscopic Determination of Manganese Concentration Page 2 of 7
3 A second complication that arises is determining a suitable wavelength to use to measure the light absorbance of the colored species in solution. It is important to choose a wavelength where the solution strongly absorbs light. Consider, for example, a red compound in an aqueous solution. If white light (containing all colors) illuminates this solution, the compound will absorb wavelengths in the yellow/green/blue region of the color spectrum, while transmitting (or reflecting) wavelengths in the red region of the spectrum. In other words, a solution that appears red in color to the eye looks red because it absorbs most colors except for red. It is the transmitted light that gives rise to the color that we see. Thus when studying a red solution it would be far better to use green light which is strongly absorbed by the solution; rather than orange or red light because these colors would be much less strongly absorbed. The stronger the absorption at a particular wavelength the more sensitive the instrument will be at that wavelength and the more accurate your results. Notice that green is the complementary color to red. A Color Wheel is a useful guide for choosing complementary colors, and one is provided below. Given that the solutions you will analyze in this lab are purple-violet what color of light would be most suitable for your absorbance measurements? Color Wheel Since each color of visible light corresponds to a characteristic wavelength, shown in the Visible Color Spectrum below, what wavelength of light would be most suitable for your absorbance measurements? Visible Color Spectrum Wavelength (nm) Spectroscopic Determination of Manganese Concentration Page 3 of 7
4 Due to time constraints in this lab, students will simply use the Color Wheel and Visible Color Spectrum to select a suitable wavelength to use. However, the standard best practice is to measure the absorbance of the solution in question across a range of wavelengths, and then select the wavelength for which the solution has the highest absorbance. For example, for the hypothetical red solution described, the experimenter might choose to measure the absorbance of the sample over the range of wavelengths between 480 nm and 560 nm, and then narrow-in on the wavelength that gives the greatest numeric value of the absorbance. While some spectrometers (scanning spectrometers) can do this automatically; others require changing the wavelength manually and each time the wavelength is adjusted these instruments need to be re-zeroed or they will not work properly. Procedure Chemicals Mn 2+ stock solution (~0.3 mg/ml), 9 M H 3 PO 4 (aq), KIO 4 (s), Mn 2+ unknown solution Equipment In Locker/Lab: 50-mL beaker, 400-mL beaker, 100-mL graduated cylinder, glass stirring rod, watch glass, stand, ring clamp, wire gauze, Bunsen burner, wash bottle with deionized water. From Stockroom: two mL volumetric flasks, four mL volumetric flasks, two cuvettes, two 5-mL volumetric pipets, one 1-mL volumetric pipet, one 2-mL volumetric pipet, one 10-mL volumetric pipet, KimWipes, UV-VIS Spectrophotometer. Note: Each pair of students will use their own locker/lab equipment. The stockroom items will be shared by teams of 4 students. Safety and Waste Disposal The PPE for this lab includes safety goggles, lab coat and nitrile gloves. Exercise appropriate caution when using the phosphoric acid (in Step 3) as it can cause serious chemical burns to your skin. Wear your nitrile gloves while handling this chemical! If any acid comes into contact with your skin or eyes, immediately rinse the affected areas with copious amounts of water for 15 minutes, and inform your instructor. Exercise appropriate caution when using the potassium periodate (in Steps 4 and 5). It is a powerful oxidant and must be kept away from open flames and combustible materials, including paper and wood. It is highly irritating to skin, eyes and mucous membranes (if inhaled). Wear your nitrile gloves while handling this chemical! If any comes into contact with your skin or eyes, immediately rinse the affected areas with copious amounts of water for 15 minutes, and inform your instructor. Many of the chemicals used in this lab are hazardous to the environment. All waste must be disposed of in the hazardous-waste container in the fume hood. Rinse all glassware directly into the waste container using a small squirt bottle to be certain all hazardous waste ends up in the waste container. Spectroscopic Determination of Manganese Concentration Page 4 of 7
5 Experiment Instructions General Notes Students will work in teams of 4 for this lab, but they will split into two groups of 2 Group A and Group B for some parts of the lab. Group A will prepare the Standard Solution (Part A) and Group B will prepare the Unknown Solution (Part B) at the same time. The two groups will perform the rest of lab together and share the data they collect. Several steps of this lab involve pipetting solutions with volumetric pipets. Be sure to rinse the pipets before use first with deionized water and then with a small amount of the solution you will be pipetting. There will be several spectrophotometers set out in the lab for student use. Your instructor will provide directions on how to use them correctly at the beginning of the lab session. Students must use the same spectrophotometer to collect all of their absorbance data. Part A: Preparing the Standard Solution (Group A) 1. In a clean, dry 50-mL beaker obtain roughly 10 ml of the Mn 2+ stock solution from the reagent bottle in the hood. Then, using a 5-mL volumetric pipet, accurately pipette 5.00 ml of this stock solution into a clean 400-mL beaker. Record this volume and the concentration of the stock solution (on the label of the bottle, ~0.3 mg/ml) on your report form. 2. Using a clean 100-mL graduated cylinder to measure volumes, add about 30 ml of deionized water to the Mn 2+ solution in the 400-mL beaker. 3. Wear gloves during this step. Measure out approximately 10 ml of 9 M phosphoric acid, H 3 PO 4 (aq), using the same 100-mL graduated cylinder, and add this acid to the solution in the 400-mL beaker. Be extremely careful when handling the phosphoric acid as it will cause serious burns if it comes in contact with your skin. Thoroughly rinse out the graduated cylinder with deionized water after performing this step, and pour the rinse water into the waste container. 4. Wear gloves during this step. Using a watch glass, weigh out approximately 0.03 grams of solid potassium periodate, KIO 4 (s). Be extremely careful when handling the potassium iodate as it is highly irritating to the skin and eyes. Keep it away from open flames and combustible materials, including paper. 5. Add the KIO 4 (s) to your solution and stir to dissolve it using a glass stirring rod. Rinse any KIO 4 (s) that sticks to the watch glass directly into the beaker using deionized water. Leave the stirring rod in the beaker to help control bubble formation when boiling. 6. Perform this step in the hood. Boil the solution gently in the hood (you will need to assemble a stand, ring clamp, wire gauze and Bunsen burner to do this). Be careful to avoid splattering and boiling over. The solution should turn purple within a few minutes. If this doesn t happen, you will need to add an extra 0.01 grams of the KIO 4 (s) to the solution. Continue boiling gently for another two minutes after the color changes to purple in order to be certain that the color change is complete. Then turn off the flame to avoid over-oxidation of the solution, which results in a rust-brown color. If this happens you will need to start all over again! Spectroscopic Determination of Manganese Concentration Page 5 of 7
6 7. Cool the solution, then pour it into a clean mL volumetric flask using a funnel. Then rinse the beaker and the funnel with deionized water and pour this rinse water to the volumetric flask. This is to ensure that all of the manganese solution is transferred. 8. Dilute the solution in the volumetric flask with deionized water to exactly the index mark and swirl to mix thoroughly. 9. Label the flask Standard Solution to avoid any mistakes or confusion. Record the color and the total volume of this solution on your report form. 10. Calculate the concentration of MnO 4 in the Standard Solution. Since the Standard Solution was obtained by diluting the stock solution, simply by apply the dilution equation to determine its concentration: C 1 V 1 = C 2 V 2. Part B: Preparing the Unknown Solution (Group B) 11. Obtain an original sample of Mn 2+ unknown solution in a large test tube from your instructor. Record the ID code of this solution on your report form. Then, using a 5-mL volumetric pipet, accurately pipette 5.00 ml of this unknown solution into a clean 400-mL beaker. Record this volume on your report form. 12. Now follow Steps 2 8 to prepare your unknown sample. 13. When finished with Step 8 label the flask Diluted Unknown Solution to avoid any mistakes or confusion. Record the color and total volume of this solution on your report form. Part C: Preparing Dilutions of the Standard Solution (Groups A and B together) 14. Label four clean mL volumetric flasks: 1, 2, 3, and Each student in the team of 4 is required to prepare one of the dilutions. Decide among yourselves which dilution each team member is assigned to prepare. Flask 1: Accurately pipette 1.00 ml of the standard solution into Flask 1 (using a 1-mL well. Label the flask Solution 1. Record the volume of standard solution pipetted and the total volume of Solution 1 on your report form. Flask 2: Accurately pipette 2.00 ml of the standard solution into Flask 2 (using a 2-mL well. Label the flask Solution 2. Record the volume of standard solution pipetted and the total volume of Solution 2 on your report form. Flask 3: Accurately pipette 5.00 ml of the standard solution into Flask 3 (using a 5-mL well. Label the flask Solution 3. Record the volume of standard solution pipetted and the total volume of Solution 3 on your report form. Flask 4: Accurately pipette ml of the standard solution into Flask 4 (using a 10-mL well. Label the flask Solution 4. Record the volume of standard solution pipetted and the total volume of Solution 4 on your report form. Spectroscopic Determination of Manganese Concentration Page 6 of 7
7 16. Calculate the concentrations of MnO 4 in Solutions 1 4. Since these solutions were obtained by diluting the standard solution, simply by apply the dilution equation to determine their concentrations: C 1 V 1 = C 2 V 2. Part D: Measuring Solution Absorbances (Groups A and B together) 17. Your team will only be supplied with two cuvettes. Rinse them with deionized water and dry the outside of each cuvette using a KimWipe. 18. Use one cuvette for the blank and fill it ¾ full with deionized water. You will use the other cuvette to measure the absorbance of MnO 4 in all your prepared solutions. 19. Before measuring the absorbance of your solutions you will need to choose a wavelength and zero your spectrometer. Your instructor will show you how to zero the spectrometer using the blank. However, it is up to your team to determine the best wavelength to use for this experiment a poor choice of wavelengths will result in poor data. See the introduction to this experiment for information on how to choose a good wavelength (if necessary). 20. Once you have selected a wavelength and zeroed the instrument, measure the absorbance of MnO 4 in all your prepared solutions using your second cuvette (fill ¾ full each time) in the following order: Solution 1, Solution 2, Solution 3, Solution 4, Standard Solution, and Diluted Unknown Solution. Note that you will have to rinse this cuvette thoroughly between measurements, each time using a small amount of deionized water and then a small amount of the sample to be added. Record all your absorbance measurements on your report form. Part E: Data Analysis 21. Using the data collected for these 5 solutions (with known MnO 4 concentrations), prepare a graph of Absorbance versus Concentration with Microsoft Excel. Apply a best-fit line to the plotted data, and obtain the equation of the line and the R 2 value. Print out a full-sized copy of your graph (fully labeled!) and attach it to your report form. 22. Calculate the MnO 4 concentration in the Diluted Unknown Solution using the equation of the trendline and the measured solution absorbance. 23. Because this is a diluted solution, you will now need to calculate backwards from this concentration to determine the actual concentration of Mn 2+ in your original unknown sample. Spectroscopic Determination of Manganese Concentration Page 7 of 7
Measuring Manganese Concentration Using Spectrophotometry
Measuring Manganese Concentration Using Spectrophotometry Objectives To use spectroscopy to determine the amount of Manganese is an unknown sample. Scenario Your have just joined a "Green Team" at SMC
More informationReaction Stoichiometry and the Formation of a Metal Ion Complex
Reaction Stoichiometry and the Formation of a Metal Ion Complex Objectives The objectives of this laboratory are as follows: To use the method of continuous variation to determine the reaction stoichiometry
More informationEXPERIMENT 11 UV/VIS Spectroscopy and Spectrophotometry: Spectrophotometric Analysis of Potassium Permanganate Solutions.
EXPERIMENT 11 UV/VIS Spectroscopy and Spectrophotometry: Spectrophotometric Analysis of Potassium Permanganate Solutions. Outcomes After completing this experiment, the student should be able to: 1. Prepare
More informationEXPERIMENT 5. Molecular Absorption Spectroscopy: Determination of Iron With 1,10-Phenanthroline
EXPERIMENT 5 Molecular Absorption Spectroscopy: Determination of Iron With 1,10-Phenanthroline UNKNOWN Submit a clean, labeled 100-mL volumetric flask to the instructor so that your unknown iron solution
More informationSolubility Product Constants
Solubility Product Constants PURPOSE To measure the solubility product constant (K sp ) of copper (II) iodate, Cu(IO 3 ) 2. GOALS 1 To measure the molar solubility of a sparingly soluble salt in water.
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 informationDetermination of the Mass Percentage of Copper in a Penny. Introduction
Determination of the Mass Percentage of Copper in a Penny Introduction This experiment will cost you one penny ($0.01). The penny must be minted after 1983. Any penny will do; for best results the penny
More informationColorimetric Determination of Iron in Vitamin Tablets
Cautions: 6 M hydrochloric acid is corrosive. Purpose: To colorimetrically determine the mass of iron present in commercial vitamin tablets using a prepared calibration curve. Introduction: Iron is considered
More informationGraphite Furnace AA, Page 1 DETERMINATION OF METALS IN FOOD SAMPLES BY GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROSCOPY (VERSION 1.
Graphite Furnace AA, Page 1 DETERMINATION OF METALS IN FOOD SAMPLES BY GRAPHITE FURNACE ATOMIC ABSORPTION SPECTROSCOPY I. BACKGROUND (VERSION 1.0) Atomic absorption spectroscopy (AAS) is a widely used
More informationAustin Peay State University Department of Chemistry Chem 1111. The Use of the Spectrophotometer and Beer's Law
Purpose To become familiar with using a spectrophotometer and gain an understanding of Beer s law and it s relationship to solution concentration. Introduction Scientists use many methods to determine
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 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 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 informationAcid Base Titrations
Acid Base Titrations Introduction A common question chemists have to answer is how much of something is present in a sample or a product. If the product contains an acid or base, this question is usually
More informationATOMIC ABSORTION SPECTROSCOPY: rev. 4/2011 ANALYSIS OF COPPER IN FOOD AND VITAMINS
1 ATOMIC ABSORTION SPECTROSCOPY: rev. 4/2011 ANALYSIS OF COPPER IN FOOD AND VITAMINS Buck Scientific Atomic Absorption Spectrophotometer, Model 200 Atomic absorption spectroscopy (AAS) has for many years
More informationCHEM 161: Beer s Law and Analysis of a Sports Drink
CHEM 161: Beer s Law and Analysis of a Sports Drink Introduction Although sunlight appears white, it contains a spectrum of colors. A rainbow actually shows this range of colors in visible light: violet,
More informationUpon completion of this lab, the student will be able to:
1 Learning Outcomes EXPERIMENT B4: CHEMICAL EQUILIBRIUM Upon completion of this lab, the student will be able to: 1) Analyze the absorbance spectrum of a sample. 2) Calculate the equilibrium constant for
More informationExperiment 13H THE REACTION OF RED FOOD COLOR WITH BLEACH 1
Experiment 13H FV 1/25/2011(2-run) THE REACTION OF RED FOOD COLOR WITH BLEACH 1 PROBLEM: Determine the rate law for the chemical reaction between FD&C Red Dye #3 and sodium hypochlorite. LEARNING OBJECTIVES:
More informationDetermining the Free Chlorine Content of Swimming Pool Water. HOCl H + + OCl. Evaluation copy
Determining the Free Chlorine Content of Swimming Pool Water Computer 33 Physicians in the nineteenth century used chlorine water as a disinfectant. Upon the discovery that certain diseases were transmitted
More informationPhenolphthalein-NaOH Kinetics
Phenolphthalein-NaOH Kinetics Phenolphthalein is one of the most common acid-base indicators used to determine the end point in acid-base titrations. It is also the active ingredient in some laxatives.
More informationLab #11: Determination of a Chemical Equilibrium Constant
Lab #11: Determination of a Chemical Equilibrium Constant Objectives: 1. Determine the equilibrium constant of the formation of the thiocyanatoiron (III) ions. 2. Understand the application of using a
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 informationRecovery of Elemental Copper from Copper (II) Nitrate
Recovery of Elemental Copper from Copper (II) Nitrate Objectives: Challenge: Students should be able to - recognize evidence(s) of a chemical change - convert word equations into formula equations - perform
More informationUsing the Spectrophotometer
Using the Spectrophotometer Introduction In this exercise, you will learn the basic principals of spectrophotometry and and serial dilution and their practical application. You will need these skills to
More informationSpectrophotometry and the Beer-Lambert Law: An Important Analytical Technique in Chemistry
Spectrophotometry and the Beer-Lambert Law: An Important Analytical Technique in Chemistry Jon H. Hardesty, PhD and Bassam Attili, PhD Collin College Department of Chemistry Introduction: In the last lab
More informationINTRODUCTION TO SPECTROMETRY
Experiment 11 INTRODUCTION TO SPECTROMETRY Portions adapted by Ross S. Nord and Colleagues, Chemistry Department, Eastern Michigan University from ANAL 043, written by Donald F. Clemens and Warren A. McAllister,
More informationCOMMON LABORATORY APPARATUS
COMMON LABORATORY APPARATUS Beakers are useful as a reaction container or to hold liquid or solid samples. They are also used to catch liquids from titrations and filtrates from filtering operations. Bunsen
More informationLab 25. Acid-Base Titration and Neutralization Reactions: What Is the Concentration of Acetic Acid in Each Sample of Vinegar?
Lab 25. Acid-Base Titration and Neutralization Reactions: What Is the Concentration of Acetic Acid in Each Sample of Vinegar? Introduction Vinegar is basically a solution of acetic acid (CH3COOH). It is
More informationLab 2. Spectrophotometric Measurement of Glucose
Lab 2 Spectrophotometric Measurement of Glucose Objectives 1. Learn how to use a spectrophotometer. 2. Produce a glucose standard curve. 3. Perform a glucose assay. Safety Precautions Glucose Color Reagent
More informationCoordination Compounds with Copper (II) Prelab (Week 2)
Coordination Compounds with Copper (II) Prelab (Week 2) Name Total /10 SHOW ALL WORK NO WORK = NO CREDIT 1. What is the purpose of this experiment? 2. Write the generic chemical formula for the coordination
More informationThe Empirical Formula of a Compound
The Empirical Formula of a Compound Lab #5 Introduction A look at the mass relationships in chemistry reveals little order or sense. The ratio of the masses of the elements in a compound, while constant,
More informationAcetic Acid Content of Vinegar: An Acid-Base Titration E10-1
Experiment 10 Acetic Acid Content of Vinegar: An Acid-Base Titration E10-1 E10-2 The task The goal of this experiment is to determine accurately the concentration of acetic acid in vinegar via volumetric
More informationTo determine the equivalence points of two titrations from plots of ph versus ml of titrant added.
Titration Curves PURPOSE To determine the equivalence points of two titrations from plots of ph versus ml of titrant added. GOALS 1 To gain experience performing acid-base titrations with a ph meter. 2
More informationCalcium Analysis by EDTA Titration
Calcium Analysis by EDTA Titration ne of the factors that establish the quality of a water supply is its degree of hardness. The hardness of water is defined in terms of its content of calcium and magnesium
More informationExperiment 2 Kinetics II Concentration-Time Relationships and Activation Energy
2-1 Experiment 2 Kinetics II Concentration-Time Relationships and Activation Energy Introduction: The kinetics of a decomposition reaction involving hydroxide ion and crystal violet, an organic dye used
More informationGeneral Chemistry I (FC, 09-10) Lab #3: The Empirical Formula of a Compound. Introduction
General Chemistry I (FC, 09-10) Introduction A look at the mass relationships in chemistry reveals little order or sense. The ratio of the masses of the elements in a compound, while constant, does not
More informationChemistry 111 Lab: Intro to Spectrophotometry Page E-1
Chemistry 111 Lab: Intro to Spectrophotometry Page E-1 SPECTROPHOTOMETRY Absorption Measurements & their Application to Quantitative Analysis study of the interaction of light (or other electromagnetic
More informationTo determine the mass of iron in one adult dose of either a ferrous sulfate or. ferrous gluconate iron supplement using a colorimetric technique.
Lab: Colorimetric Analysis of Iron in Iron Supplements Purpose To determine the mass of iron in one adult dose of either a ferrous sulfate or ferrous gluconate iron supplement using a colorimetric technique.
More informationPREPARATION AND PROPERTIES OF A SOAP
(adapted from Blackburn et al., Laboratory Manual to Accompany World of Chemistry, 2 nd ed., (1996) Saunders College Publishing: Fort Worth) Purpose: To prepare a sample of soap and to examine its properties.
More informationSeparation and Identification of Plant Pigments Dr. Gergens - SD Mesa College
Separation and Identification of Plant Pigments Dr. Gergens - SD Mesa College PURPOSE In this experiment, the photosynthetic pigments common to all flowering plants will be extracted by liquidliquid extraction.
More informationKINETIC DETERMINATION OF SELENIUM BY VISIBLE SPECTROSCOPY (VERSION 1.8)
Selenium Determination, Page 1 KINETIC DETERMINATION OF SELENIUM BY VISIBLE SPECTROSCOPY I. BACKGROUND. (VERSION 1.8) The majority of reactions used in analytical chemistry possess the following characteristics:
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 informationAscorbic Acid Titration of Vitamin C Tablets This lab will be completed individually! Make sure you come prepared!
Ascorbic Acid Titration of Vitamin C Tablets This lab will be completed individually! Make sure you come prepared! Introduction Vitamin C (also known as ascorbic acid, HC6H7O6) is a necessary ingredient
More informationChem 131A: Absorbance of Riboflavin
Chem 131A: Absorbance of Riboflavin Purpose: The purpose of this experiment is to: 1) Familiarize the student with the use of the HP 8452 diode array spectrophotometer, 2) examine the limitations of the
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 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 informationEXPERIMENT 7 Electrochemical Cells: A Discovery Exercise 1. Introduction. Discussion
EXPERIMENT 7 Electrochemical Cells: A Discovery Exercise 1 Introduction This lab is designed for you to discover the properties of electrochemical cells. It requires little previous knowledge of electrochemical
More informationANALYSIS OF VITAMIN C
Purpose To learn how to analyze food for vitamin C content and to examine various sources for vitamin C content. Caution Handle the glassware with caution to prevent breakage. When using a burner in the
More information2 Spectrophotometry and the Analysis of Riboflavin
2 Spectrophotometry and the Analysis of Riboflavin Objectives: A) To become familiar with operating the Platereader; B) to learn how to use the Platereader in determining the absorption spectrum of a compound
More informationExperiment 8 Synthesis of Aspirin
Experiment 8 Synthesis of Aspirin Aspirin is an effective analgesic (pain reliever), antipyretic (fever reducer) and anti-inflammatory agent and is one of the most widely used non-prescription drugs. The
More informationColorimetric Determination of Iron in Vitamin Tablets
Colorimetric Determination of Iron in Vitamin Tablets Big Picture Conceptual Approach Vitamin Tablet How much Fe? ph = 3.5 Vitamin Tablet How much Fe? Too difficult to eyeball so will have the colorimeter
More informationThe Determination of an Equilibrium Constant
The Determination of an Equilibrium Constant Chemical reactions occur to reach a state of equilibrium. The equilibrium state can be characterized by quantitatively defining its equilibrium constant, K
More information2.02 DETERMINATION OF THE FORMULA OF A COMPLEX BY SPECTROPHOTOMETRY
2nd/3rd Year Physical Chemistry Practical Course, Oxford University 2.02 DETERMINATION OF THE FORMULA OF A COMPLEX BY SPECTROPHOTOMETRY (4 points) Outline Spectrometry is widely used to monitor the progress
More informationChemistry 2351: Inorganic Chemistry I Laboratory Manual
Spectroscopic Determination of a Complex Ion's Stoichiometry by Job's Method ABSTRACT This experiment is adapted from Angelici's classic experiment, but uses Fe(H 2 O) 6-n (SCN) n 3-n as the complex ion.
More informationEvaluation copy. Case File 9. A Killer Cup of Coffee? GlobalTech manager dies
Case File 9 Killer Cup of Coffee: Using colorimetry to determine concentration of a poison Determine the concentration of cyanide in the solution. A Killer Cup of Coffee? SOUTH PAINTER, Tuesday: It was
More informationExperiment 8 - Double Displacement Reactions
Experiment 8 - Double Displacement Reactions A double displacement reaction involves two ionic compounds that are dissolved in water. In a double displacement reaction, it appears as though the ions are
More informationAN EXPERIMENT IN ALCHEMY: COPPER TO SILVER TO GOLD 2005, 2000, 1996 by David A. Katz. All rights reserved
AN EXPERIMENT IN ALCHEMY: COPPER TO SILVER TO GOLD 2005, 2000, 1996 by David A. Katz. All rights reserved INTRODUCTION One of the goals of the ancient alchemists was to convert base metals into gold. Although
More informationAnalysis of Vitamin C Using Iodine. Introduction
Analysis of Vitamin C Using Iodine Introduction Vitamin C (ascorbic acid) is oxidized to dehydroascorbic acid using a mild oxidizing agent such as iodine. The oxidation is a two- electron process, following
More informationACID-BASE TITRATIONS: DETERMINATION OF CARBONATE BY TITRATION WITH HYDROCHLORIC ACID BACKGROUND
#3. Acid - Base Titrations 27 EXPERIMENT 3. ACID-BASE TITRATIONS: DETERMINATION OF CARBONATE BY TITRATION WITH HYDROCHLORIC ACID BACKGROUND Carbonate Equilibria In this experiment a solution of hydrochloric
More informationDetermination of a Chemical Formula
1 Determination of a Chemical Formula Introduction Molar Ratios Elements combine in fixed ratios to form compounds. For example, consider the compound TiCl 4 (titanium chloride). Each molecule of TiCl
More informationStoichiometry Limiting Reagent Laboratory. Chemistry 118 Laboratory University of Massachusetts, Boston
Chemistry 118 Laboratory University of Massachusetts, Boston STOICHIOMETRY - LIMITING REAGENT --------------------------------------------------------------------------------------------------------------------------------------------
More informationExperiment 12- Classification of Matter Experiment
Experiment 12- Classification of Matter Experiment 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.
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 informationLab 5: Quantitative Analysis- Phosphates in Water By: A Generous Student. LBS 171L Section 9 TA: Dana October 27, 2005
How uch Phosphate is the Body Being Exposed to During a Lifetime by Showering? Lab 5: Quantitative Analysis- Phosphates in Water By: A Generous Student LBS 171L Section 9 TA: Dana October 7, 005 [Note:
More informationDYES AND DYEING 2003 by David A. Katz. All rights reserved. Permission for classroom use provided original copyright is included.
DYES AND DYEING 2003 by David A. Katz. All rights reserved. Permission for classroom use provided original copyright is included. Dyeing of textiles has been practiced for thousands of years with the first
More informationSynthesis of Aspirin and Oil of Wintergreen
Austin Peay State University Department of hemistry hem 1121 autions Purpose Introduction Acetic Anhydride corrosive and a lachrymator all transfers should be done in the vented fume hood Methanol, Ethanol
More informationENZYME KINETICS ENZYME-SUBSTRATE PRODUCTS
ENZYME KINETICS INTRODUCTION The study of reaction rates catalyzed by enzymes and the factors affecting them is generally referred to as enzyme kinetics. The basic components of an enzyme catalyzed reaction
More informationhij Teacher Resource Bank GCE Chemistry PSA10: A2 Inorganic Chemistry Carry out a redox titration
hij Teacher Resource Bank GCE Chemistry : A2 Inorganic Chemistry Copyright 2009 AQA and its licensors. All rights reserved. The Assessment and Qualifications Alliance (AQA) is a company limited by guarantee
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 7 Reaction Stoichiometry and Percent Yield
EXPERIMENT 7 Reaction Stoichiometry and Percent Yield INTRODUCTION Stoichiometry calculations are about calculating the amounts of substances that react and form in a chemical reaction. The word stoichiometry
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 informationDissolving of sodium hydroxide generates heat. Take care in handling the dilution container.
TITRATION: STANDARDIZATION OF A BASE AND ANALYSIS OF STOMACH ANTACID TABLETS 2009, 1996, 1973 by David A. Katz. All rights reserved. Reproduction permitted for education use provided original copyright
More informationSugar or Salt? Ionic and Covalent Bonds
Lab 11 Sugar or Salt? Ionic and Covalent Bonds TN Standard 2.1: The student will investigate chemical bonding. Have you ever accidentally used salt instead of sugar? D rinking tea that has been sweetened
More informationChemistry 111 Laboratory Experiment 7: Determination of Reaction Stoichiometry and Chemical Equilibrium
Chemistry 111 Laboratory Experiment 7: Determination of Reaction Stoichiometry and Chemical Equilibrium Introduction The word equilibrium suggests balance or stability. The fact that a chemical reaction
More informationJuice Titration. Background. Acid/Base Titration
Juice Titration Background Acids in Juice Juice contains both citric and ascorbic acids. Citric acid is used as a natural preservative and provides a sour taste. Ascorbic acid is a water-soluble vitamin
More informationUniversity of Wisconsin Chemistry 524 Spectroscopic Applications (GFAA, ICP, UV/Vis, Fluorescence)
University of Wisconsin Chemistry 524 Spectroscopic Applications (GFAA, ICP, UV/Vis, Fluorescence) For this laboratory exercise, you will explore a variety of spectroscopic methods used in an analytical
More informationUnderstanding Analytical Chemistry (Weighing, Mixing, Measuring and Evaluating)
Name: Date: Understanding Analytical Chemistry (Weighing, Mixing, Measuring and Evaluating) High School Environmental Science AP Module 1 Environmental Lab NGSSS Big Ideas: This module is a laboratory-based
More informationStoichiometry Limiting Reagent Laboratory. Chemistry 118 Laboratory University of Massachusetts, Boston
Chemistry 118 Laboratory University of Massachusetts, Boston STOICHIOMETRY - LIMITING REAGENT -----------------------------------------------------------------------------------------------------------------------------
More informationExperiment 7: Titration of an Antacid
1 Experiment 7: Titration of an Antacid Objective: In this experiment, you will standardize a solution of base using the analytical technique known as titration. Using this standardized solution, you will
More informationEXPERIMENT 4. Determination of Sodium by Flame Atomic-Emission Spectroscopy
EXPERIMENT 4 Determination of Sodium by Flame Atomic-Emission Spectroscopy USE ONLY DEIONIZED WATER (NOT DISTILLED WATER!) THROUGHOUT THE ENTIRE EXPERIMENT Distilled water actually has too much sodium
More informationEFFECT OF SALT ON CELL MEMBRANES
EFFECT OF SALT ON CELL MEMBRANES LAB CELL 2 INTRODUCTION A eukaryotic cell, a cell with a nucleus, not only has a plasma membrane as its external boundary, but it also has a variety of membranes that divide
More informationBACKGROUND INFORMATION
BACKGROUND INFORMATION It is often important to measure the concentration of glucose in a solution. The so-called ISOTONIC drinks can be tested to see if they are in fact isotonic with the blood. You may
More informationDetermining the Identity of an Unknown Weak Acid
Purpose The purpose of this experiment is to observe and measure a weak acid neutralization and determine the identity of an unknown acid by titration. Introduction The purpose of this exercise is to identify
More informationDetermination of calcium by Standardized EDTA Solution
Determination of calcium by Standardized EDTA Solution Introduction The classic method of determining calcium and other suitable cations is titration with a standardized solution of ethylenediaminetetraacetic
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 informationRelated concepts Kohlrausch s law, equivalent conductivity, temperature dependence of conductivity, Ostwald s dilution law.
Conductivity of strong and weak electrolytes TEC Related concepts Kohlrausch s law, equivalent conductivity, temperature dependence of conductivity, Ostwald s dilution law. Principle It is possible to
More informationChapter 5 -- The Spectrophotometric Determination of the ph of a Buffer. NAME: Lab Section: Date: Sign-Off:
Chapter 5 -- The Spectrophotometric Determination of the ph of a Buffer NAME: Lab Section: Date: Sign-Off: Chapter 5 -- The Spectrophotometric Determination of the ph of a Buffer Introduction Weak acids,
More informationEstimation of Alcohol Content in Wine by Dichromate Oxidation followed by Redox Titration
Sirromet Wines Pty Ltd 850-938 Mount Cotton Rd Mount Cotton Queensland Australia 4165 www.sirromet.com Courtesy of Jessica Ferguson Assistant Winemaker & Chemist Downloaded from seniorchem.com/eei.html
More informationEDTA Titrations 1: Standardization of EDTA and Analysis of Zinc in a Supplement Tablet. by Professor David Cash. September, 2008
CHEMICAL, ENVIRONMENTAL, AND BIOTECHNOLOGY DEPARTMENT EDTA Titrations 1: Standardization of EDTA and Analysis of Zinc in a Supplement Tablet by Professor David Cash September, 2008 Mohawk College is the
More informationSTANDARDIZATION OF A SODIUM HYDROXIDE SOLUTION EXPERIMENT 14
STANDARDIZATION OF A SODIUM HYDROXIDE SOLUTION EXPERIMENT 14 OBJECTIVE The objective of this experiment will be the standardization of sodium hydroxide using potassium hydrogen phthalate by the titration
More informationChemistry 118 Laboratory University of Massachusetts Boston Beer s Law
Name: LEARNING GOALS: Chemistry 118 Laboratory University of Massachusetts Boston Beer s Law 1. Become familiar with the concept of concentration and molarity. 2. Become familiar with making dilutions
More informationPhosphates (ortho- and total)
INTRODUCTION Phosphates (ortho- and total) Phosphorus is an essential nutrient for all aquatic plants and algae. Only a very small amount is needed, however, so an excess of phosphorus can easily occur.
More informationMetalloids will also react with oxygen. Upon reaction with oxygen silicon forms silicon dioxide, the main component of sand.
The Preparation and Properties of xygen Reading assignment: Chang, Chemistry 10 th edition, pp. 135-141. Goals We will observe the thermal decomposition of several oxygen-containing compounds called oxides.
More informationMASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Chemistry 5.310 Laboratory Chemistry THE POTENTIOMETRIC TITRATION OF AN ACID MIXTURE 1
MASSACHUSETTS INSTITUTE OF TECHNOLOGY Department of Chemistry 5.310 Laboratory Chemistry EXPERIMENT #5 THE POTENTIOMETRIC TITRATION OF AN ACID MIXTURE 1 I. PURPOSE OF THE EXPERIMENT In this experiment
More informationProject 5: Scoville Heat Value of Foods HPLC Analysis of Capsaicinoids
Willamette University Chemistry Department 2013 Project 5: HPLC Analysis of Capsaicinoids LABORATORY REPORT: Formal Writing Exercises PRE-LAB ASSIGNMENT Read the entire laboratory project and section 28C
More information18 Conductometric Titration
Lab Activity 18 CONDUCTOMETRIC TITRATION LAB ACTIVITY 18 Conductometric Titration Background Titration is the a method of determining the concentration of an unknown solution (the analyte) by reacting
More informationGlobalTech manager dies
Case File 9 Killer Cup of Coffee: Using colorimetry to determine concentration of a poison Determine the concentration of cyanide in the solution. A Killer Cup of Coffee? GlobalTech manager dies SOUTH
More informationPREPARATION FOR CHEMISTRY LAB: COMBUSTION
1 Name: Lab Instructor: PREPARATION FOR CHEMISTRY LAB: COMBUSTION 1. What is a hydrocarbon? 2. What products form in the complete combustion of a hydrocarbon? 3. Combustion is an exothermic reaction. What
More informationOXIDATION-REDUCTION TITRATIONS-Permanganometry
Experiment No. Date OXIDATION-REDUCTION TITRATIONS-Permanganometry INTRODUCTION Potassium permanganate, KMnO 4, is probably the most widely used of all volumetric oxidizing agents. It is a powerful oxidant
More informationStage 1 Desired Results
Lesson Title: Phosphate Testing Contract Discipline Focus: Chemistry Grade level: 11-12 Length of lesson: 1.5 class periods Content Standard(s): Stage 1 Desired Results Understanding (s)/goals Students
More information