...Fat and Oil Peroxide value of Oleic acid Redox titration by Automatic Potentiometric Titrator Standard Test Method for Analysis of Basic Fatty Material ISO 3960 1. Abstract The oleic acid is widely distributed in plant and animal fats. Measurement of peroxide value (POV) of oleic acid is demonstrated in this application according to the below quoted test method. The test sample is first dissolved in mixture of chloroform and acetic acid（2：3）. By flowing nitrogen gas through the sample to dispel residual oxygen, add potassium iodide, and then titrate free iodine with 0.01mol/L sodium thiosulfate. The endpoint is determined by the maximum inflexion point on titration curve. POV is calculated from titration volume of sodium thiosulfate. I2 + 2Na2S2O3 → Na2S4O6 + 2NaI 2. Reference 1) Test Method for Analysis of Basic Fatty Material by Japanese Oil Chemistry Society; Reference material 2.4-1996 Peroxide value （Chloroform Method） 2) ISO 3960 : 2007 Animal and vegetable fats and oils – Determination of peroxide value 3. Cautions in measurement 1) Do not use water containing carbon dioxide in preparing saturated potassium iodide solution. 2) To confirm saturation, add excessive potassium iodide to the saturated potassium iodide solution, and leave crystal in the solution. 3) Prepare fresh saturated potassium iodide each time. 4) If the sample does not change color to yellow due to free iodine when saturated potassium iodide is added, add more saturated potassium iodide...
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...Elijah Kim Mrs. Dobler Course 2 2/10/15 Titration lab Titration is used to find the specific amount of a standard solution in an amount of unknown liquid. Titration in this lab is performed with the chemical reactions between acids and liquids. During titration, we have to stop at the point where stoichiometric amounts of acids and bases are reacting. We can find that point by looking for indicators, for example in this lab the indicators were changes in color. So the purpose of all this is to determine the concentration of some acid solutions. 1. Measure 10 mL of your acid solution using graduated cylinder and and it to the Erlenmeyer flask 2. Add about 25 mL of distilled water to the flask 3. Place your Erlenmeyer flask under the buret and a white piece of paper under you Erlenmeyer flask 4. Record the initial buret reading 5. Start adding the NaOH to the flask dropwise, stopping at a faint pink point. 6. Record final buret reading 7. Repeat for a second and third trial Trial one Trial two Trial three Volume of acid sample: 10 mL 10 mL 10 mL Final Buret reading: 20.22 29.8 40.1 Initial Buret reading: 10.63 20.22 29.8 Net volume NaOH used: 9.6 9.6 10.3 Calculations Trial one Trial two Trial three Moles NaOH reacted: ...
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...NATIONAL QUALIFICATIONS CURRICULUM SUPPORT Chemistry A Practical Guide Support Materials [REVISED ADVANCED HIGHER] [pic] The Scottish Qualifications Authority regularly reviews the arrangements for National Qualifications. Users of all NQ support materials, whether published by Education Scotland or others, are reminded that it is their responsibility to check that the support materials correspond to the requirements of the current arrangements. Acknowledgement © Crown copyright 2012. You may re-use this information (excluding logos) free of charge in any format or medium, under the terms of the Open Government Licence. To view this licence, visit http://www.nationalarchives.gov.uk/doc/open-government-licence/ or e-mail: psi@nationalarchives.gsi.gov.uk. Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned. Any enquiries regarding this document/publication should be sent to us at enquiries@educationscotland.gov.uk. This document is also available from our website at www.educationscotland.gov.uk. Contents Introduction 5 Chemical analysis 6 Qualitative and quantitative analysis 6 Volumetric analysis 6 Gravimetric analysis 14 Colorimetric analysis 17 Organic techniques 22 Introduction 22 Preparation 22 Isolation 24 Purification 29 Identification...
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...solution can be standardized by titration against a standard solution of ammonium iron(II) sulphate solution. This is an example of standardization, which is a process to determine the concentration of a solution by using it to titrate another solution which have a known concentration. This titration is known as redox titration as the titrant, which is the potassium permanganate is a strong oxidizing agent. The ammonium iron (II) sulphate solution is measured by using a pipette and transfer it into a conical flask while the potassium permanganate solution is placed in a burette. The ammonium iron (II) sulphate solution is made acidic by adding dilute sulphuric acid. Potassium permanganate solution is dark purple colour because of the presence of permanganate ions, MnO4- . Since potassium permanganate is a strong oxidizing agent, it can oxidizes iron(II) ions to iron(III) ions. Fe2+ Fe3+ + e- On the other hand, the Mn7+ ions of the dark purple colour permanganate ion, MnO4- are reduced to colourless Mn2+ ion. MnO4- + 8H+ + 5e- Mn2+ +4H2O As a result, the overall ionic equation is: MnO4- + 8 H+ + 5 Fe2+ → Mn2+ + 5 Fe3+ + 4 H2O At the end point of the titration, the colourless solution in the conical flask will change to pale pink colour. As a result, no indicator is needed. Iron (II) sulphate heptahydrate crystals, FeSO4 . 7H2O, which is a common reducing agent is not suitable to be used in this titration because it will easily oxidizes...
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...D1 – Qualitative and quantitative What is qualitative? Qualitative is represented as judgment quality of something for example colour and appearance. When checking the quality of something you don’t need to measure and weight of it, so numbers are not required to identify the substances. What is quantitative? Quantitative is checking the quantity of something such as the weight, mass and area to ensure to ensure accuracy of that specific substance. By doing this you would know the exact amount/ weight of the substance or equipment that you are using. Titration: The titration that we carried out was both qualitative and quantitative. For example when we made the standard solution for the titration we used the exact quantity of the substance and we mixed it with the exact amount of deionised water (250ml) and when we were doing the calculation to get the concentration of the standard solution we made sure to use weight of the equipment that we used. When we were caring out the titration we added indicator in the base so that the solution would turn into different colour and when we add the acid into it we would be able to tell when the end point comes because the colour will change. Qualitative and quantitative comparison: I think that quantitative technique is more important than qualitative for titration because if the measurements for titration and standard solution are not accurate and precise then then it can affect all of our result and conclusion can be completely...
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...Module 9 : Experiments in Chemistry Lecture 38 : Titrations : Acid-Base, Redox and Complexometric Objectives In this lecture you will learn the techniques to do following Determination of the amount of sodium carbonate and sodium hydroxide in a mixture by titration. Carrying out acid-base titration using a pH meter. Carrying out acid-base titration by conductometric measurement. Determination of the composition of a mixture of acetic acid and hydrochloric acid by conductometric titration. Determination of ferrous ion using potassium dichromate by internal indicator. Determination of hardness (Ca2+ ) of water using EDTA – complexometry method. In this lecture, you will be introduced to a few experiments in chemistry. These experiments complement the theory you have learned in chemical equilibrium and kinetics. 38.1 Acid-Base Titrations: Acid-base reactions are of great practical importance in analysis, not only because of their use in titrating a large number of inorganic and organic substances, but also because the hydrogen ion concentration of a solution often is of great importance in controlling reactions. Titration : The process of determining the volume of a given solution of a reagent equivalent to the amount of another reactant present in a standard solution is known as titration. Equivalent Weight of Acids and Bases : The equivalent weight of an acid is that weight which yields one mole of hydrogen ions in the reaction employed whereas the equivalent weight of...
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...POINT LISAS CAMPUS Esperanza Road, Brechin Castle, Couva www.utt.edu.tt LAB 1 Decomposition reaction Aim: Determination of the number of moles of water molecules of crystallization present in hydrated Magnesium Sulphate (MgSO4.xH2O) Apparatus: Mass balance, test tube, test tube holder, heat-proof mat and bunsen burner. Reagents: Hydrated sodium carbonate. Theory: Chemical decomposition, analysis or breakdown is the separation of a chemical compound into elements or simple compounds. A more specific type of decomposition is thermal decomposition or thermolysis, which is caused by heat. ABA+B, the reaction is endothermic, since heat is required to break the chemical bonds. Most decomposition reaction require energy either in the form of heat, light or electricity. Absorption of energy causes the breaking of the bonds present in the reacting substance which decomposes to give the product. When a hydrated salt is heated it decomposes into a pure form of the salt and water. MgSO4.xH2O MgSO4 + H2O Procedure: Refer to Handout Results: A. Mass of test tube/g = 21.77 B. Mass of the tube and salt/g = 24.0 A table showing the mass of the test tube and salt after 3 consecutive heating: Heating | Mass of the test tube and salt/g | 1st | 23.96 | 2nd | 23.81 | 3rd | 23.81 | Calculations: G. Mass of anhydrous magnesium sulphate/g = F - A = 23.81 – 21.77= 2.04 H. Mass of water of crystallization evaporated/g...
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...volumes delivered by these. In addition, you will use a suitable titration to determine the concentration of acetic (ethanoic) acid in vinegar samples. Objectives: On completion of the laboratory you should be able to: Demonstrate proper techniques for using `pipette, burette and volumetric flask. Assess the random error in the volume delivered from the pipette and a burette. Accurately dilute a sample. Use a suitable titration to determine the concentration of ethanoic acid in vinegar. Theory: All measurements (volumes, lengths, weights etc.) have associated errors. Some, called gross errors, arise from mistakes (writing down the wrong number, recording the wrong units, etc.) but these can be easily avoided by working carefully. Others, called systematic errors, arise from equipment or instruments not operating according to their specifications (for example a pipette delivers 4.96 cm3 rather than the stated 5.00 cm3) or something goes wrong with the measurement procedure (for example there is something unexpected in the sample being studied (called an interferant) that results in the measurement being different from what it would be if the interferant was not there). Systematic errors lead to inaccurate results but can be avoided if the cause of the error can be identified. The final type of errors are called random errors and result from unavoidable fluctuations in the measurement process (for example the possible variations in a burette reading that result from attempts...
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...Vitamin C Background Information Vitamins play an essential role in animal metabolic processes. They are groups of complex organic compounds that do not provide energy. However, without vitamins, animals may develop deficiency diseases or other abnormal conditions. Although most animals cannot synthesise vitamins, certain animals can. Apart from vitamin D, the human body cannot make its own vitamins. As humans, we must obtain the vitamins we require through the food that we consume. 2D Structure of Vitamin C 2D Structure of Vitamin C 3D Structure of Vitamin C 3D Structure of Vitamin C Vitamin C also known as L-Ascorbic acid is one of the most important nutrients and is essential for human beings. Vitamin C’s IUPAC name is 2-oxo-L-theo-hexono-1,4-lactone-2,3-enediol. We need a constant supply of vitamin C in our diet as the human body cannot store vitamin C because it is not a fat-soluble vitamin and where there is excess vitamin C, it is removed from the body through the urine. As well as this, vitamin C is very important in the growth and repair of tissues. It plays a crucial role in the healing of wounds and the repair and maintenance of teeth, cartilage and bones. Ascorbic acid is a “vitamer” of vitamin C that has antioxidant properties and is soluble in water to create a slightly acidic solution. A vitamer is “One of two or more related chemical substances that fulfill the same specific vitamin function”. Antioxidants block some of the damage caused by free...
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...NATIONAL QUALIFICATIONS CURRICULUM SUPPORT Chemistry A Practical Guide Support Materials [REVISED ADVANCED HIGHER] [pic] The Scottish Qualifications Authority regularly reviews the arrangements for National Qualifications. Users of all NQ support materials, whether published by Education Scotland or others, are reminded that it is their responsibility to check that the support materials correspond to the requirements of the current arrangements. Acknowledgement © Crown copyright 2012. You may re-use this information (excluding logos) free of charge in any format or medium, under the terms of the Open Government Licence. To view this licence, visit http://www.nationalarchives.gov.uk/doc/open-government-licence/ or e-mail: psi@nationalarchives.gsi.gov.uk. Where we have identified any third party copyright information you will need to obtain permission from the copyright holders concerned. Any enquiries regarding this document/publication should be sent to us at enquiries@educationscotland.gov.uk. This document is also available from our website at www.educationscotland.gov.uk. Contents Introduction 5 Chemical analysis 6 Qualitative and quantitative analysis 6 Volumetric analysis 6 Gravimetric analysis 14 Colorimetric analysis 17 Organic techniques 22 Introduction 22 Preparation 22 Isolation 24 Purification 29 Identification 33 Percentage yield 37 Errors 39 Accuracy and precision 39 Repeatability and reproducibility...
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...Elijah Kim Mrs. Dobler Course 2 2/10/15 Titration lab Titration is used to find the specific amount of a standard solution in an amount of unknown liquid. Titration in this lab is performed with the chemical reactions between acids and liquids. During titration, we have to stop at the point where stoichiometric amounts of acids and bases are reacting. We can find that point by looking for indicators, for example in this lab the indicators were changes in color. So the purpose of all this is to determine the concentration of some acid solutions. 1. Measure 10 mL of your acid solution using graduated cylinder and and it to the Erlenmeyer flask 2. Add about 25 mL of distilled water to the flask 3. Place your Erlenmeyer flask under the buret and a white piece of paper under you Erlenmeyer flask 4. Record the initial buret reading 5. Start adding the NaOH to the flask dropwise, stopping at a faint pink point. 6. Record final buret reading 7. Repeat for a second and third trial Trial one Trial two Trial three Volume of acid sample: 10 mL 10 mL 10 mL Final Buret reading: 20.22 29.8 40.1 Initial Buret reading: 10.63 20.22 29.8 Net volume NaOH used: 9.6 9.6 10.3 Calculations Trial one Trial two Trial three Moles NaOH reacted: ...
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...BTEC LEVEL 3 APPLIED SCIENCE GROUP A, MAH NOOR, 40033495 Standard Solution: * There may have been a random error whilst the titration, it has a random effect on the results, some are higher than the average value while others are lower. One of the main sources of random error is in the equipment we use in making measurements. Random errors of this type are always present and cannot be eliminated, they are a result of limitation inherent in the equipment we use and are out of our control. Some random errors can be eliminated or at least reduced. For example, we were weighing a sample of a chemical (Sodium Carbonate) near an open window. The draughts of air from the window would move the balance pan up and down, thereby decreasing or increasing the mass measurement in a random fashion. By closing the window or by surrounding the pan with a draught excluder, this random error could be eliminated. * There may have been an error whilst making standard solution, the error indentified was not mixing the standard solution properly and also not ensuring that all of the solute was transferred, because 1.5g of sodium carbonate was added to the volumetric flask and then a little bit of water was added and then we swirled the volumetric flask to dissolve the solute in the water and then added distilled water up to the line and left it, to further ensure the solute was mixed into the water and all of it was transferred properly we could have added the solute into a beaker first...
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...CHEMISTRY: MATTER AND EQUILIBRIUM Indigestion and Titration: An Acid-Base Titration Imagine yourself as the Lead Analytical Chemist at Kaplan Industries. Your first big assignment is to investigate the strength of several commercial antacids for the Food and Drug Administration (FDA). They have sent five antacids to be tested with a back-titration that works as follows: • • • First, each antacid tablet is mixed with 40 mL of 0.1 M HCl—this acidic solution is the same stuff that is in stomach acid, and one antacid pill is nowhere near enough to neutralize all 40 mL of the acid. So, to see how much extra help each antacid pill needs to neutralize 40 mL of 0.1 M HCL, you add 0.05 M NaOH drop-by-drop to back-titrate the solution until the pH is neutral. What this means is that, the stronger the antacid tablet, the less NaOH it will take to help bring the acid to neutral. (In other words, the stronger antacid tablets counteract more of the original HCl, leaving the solution closer to neutral before the NaOH is added.) Here are your results: Maalox Mass of one dose antacid mL NaOH used in backtitration 20.0 g Tums 21.0 g Mylanta 18.0 g CVS brand 18.3 g Rennies 17.5 g 24.1 mL 22.4 mL 20.0 mL 19.9 mL 24.4 mL 1. Which is the strongest antacid, on a single-dose basis? Which is the weakest? Explain and show your calculations. 2. Which are the strongest and weakest, on a by-weight (mass) basis? 3. When people do back titrations, they usually watch the solution for a color...
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...sodium carbonate accurately using the method of “weighing by difference”. Transfer the weighed carbonate to a beaker and add about 100 cm3 of distilled water to dissolve it completely. After dissolving, transfer the solution to a 250.00 cm3 volumetric flask. Rinse the beaker thoroughly and transfer all the washes into the volumetric flask. Remember not to overshoot the graduation mark of the flask. Make up the solution to the mark on the neck by adding water. Pipette 25.00 cm3 of sodium carbonate solution to a clean conical flask. Add 2 drops of methyl orange indicator to the carbonate solution. Titrate the carbonate solution with the given dilute hydrochloric acid until the colour of solution just changes from yellow to orange. Repeat the titration two times. Calculation : Results : Questions : Calculate the molarity of the sodium carbonate solution prepared and the molarity of the hydrochloric acid. 1 2. What is the meaning of “weighing by difference”? Suggest one method other than using acid-base indicator to...
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...experiment requires that you determine the concentration of an unknown solution of phosphoric acid, using a sodium hydroxide solution of known concentration that is provided to us. In the third part, we are required to prepare a solution of hydrochloric acid and measure its concentration(standardization)by titration with sodium hydroxide solution of known concentration using neutral indicator. Materials Equipments: analytical balance, 500 mL beaker, wash bottle, watch glass, measuring cylinder, Gooch crucibles, Gooch crucible rubber collar, oven, hot plate, vacuum flask, stirring rod, Chemicals: 1:1 ration HCl solution, 5M ammonia solution, deionized water, 2.0% ammonium oxalate solution, Methyl red indicator. Methods (1) Calculation of volume delivered by pipette Record the room temperature indicated on the wall-mounted thermometer( we assume that the water temperature is the same as the room temperature), the volume of the pipette can be calculated from the weight of water discharged and the density of the water at water temperature. The experiment has to be repeated 6 times. The results should be averaged and the standard deviation calculated. (2) Titration of an aliquot of phosphoric acid solution Firstly, rinse the calibrated 25 mL pipette three times with small volumes of the unknown phosphoric acid solution and deliver a 25 mL aliquot into a 100 mL conical flask.ues the calibrated delivery volume of the pipette as the quantity of phosphoric acid...
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