...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: ...
Words: 350 - Pages: 2
...Lab Report 2 – Titration CHEM1903 – Chemistry 1A (SSP) Michael West (305159240) 1. Experiment 2.2 – Titrimetric determination of the molecular mass of an organic acid Method An unknown organic acid was supplied in solid form. The acid was known to be diprotic and had the reference number 19. Using an analytical balance, 1.5397 g of the acid were weighed out, and made up with deionised water into 250 mL of solution. 25 mL of the acid solution was added to a conical flask with phenolphthalein indicator and titrated against standardized 0.0983 M NaOH solution. Three titrations were performed and the results averaged. The molar mass of the acid was then calculated and compared to a list of given possibilities. Results and Calculations The three titres were 26.30 mL, 26.50 mL and 26.30 mL. The mean titre volume was hence 26.37 mL. The number of moles of NaOH was thus moles. Because the acid was diprotic, reaction stoichiometry dictates that there was one mole of acid for every two moles of NaOH. Accordingly, in 25 mL of the acid solution, there were moles of acid. The molar mass of the acid is then g⋅mol-1. This matches most closely with succinic acid, for which the given molar mass was 118.1 g⋅mol-1. Although this represents a 0.6% discrepancy, the error is small enough to identify the acid as succinic acid with a high degree of certainty, given the possibilities listed. 2. Experiment 2.3 – Determination of the carbon dioxide and hydrogencarbonate contents of soda water...
Words: 1186 - Pages: 5
...percentage difference is 3.7 % which is significant difference to be noted. This percentage difference could occur due to many reasons such as not measuring the KHP properly as we got 0.42 g for first trial and 0.4139 g for second trial of KHP for performing titration but it is more than required value as per literature value is concerned (0.40 g). The almost same percentagedifference occurs for next two trials (1.9 % and 2.5 %). The KHP is always 99.9 % pure, so the titration should give perfect results (Lab Manual). The other possible...
Words: 598 - Pages: 3
...Telicia Peet ENG 231 3/15/2014 How to Titrate a Solution A titration is a technique where a solution of known concentration is used to determine the concentration of an unknown solution (ChemMed). In a titration a solution of a known solute (titrant) is added to a solution with an unknown solute (analyte). The chemical composition of a substance is very intricate, and learning how to titrate a solution is the most fundamental step toward determining the chemical makeup of that substance”. When a substance becomes synthesized, it is important to know that it has the chemical makeup expected. The point at which the solutions meet is known as the equivalence point; here the amounts of the two substances are stoichiometrically equivalent. The endpoint is the point at which the titration is complete (Princeton). There are numerous ways to determine the composition and structure of a substance, yet this manual demonstrates how to titrate a solution. To conduct this experiment, he or she will need a burette, an Erlenmeyer flask, a lab coat, goggles, and an unknown solution to titrate. Typically this is done in a laboratory but anywhere with an ample amount of space is fine. The burette is used to dispense accurate volumes of a substance. Attached to the burette is a stopcock that is used to release or withhold a substance. Normally the titrated solution is purple, but the color of the titrant may vary also. An Erlenmeyer flask is a piece of glassware used to pour the substance...
Words: 611 - Pages: 3
...NaOH found during the lab was very accurate because it was only 3.05% off of the true value of NaOH which was 0.197M. The first and third trial were very accurate to the true value while the second trial was 0.0134M off of the true value. Trial 2 caused the tests to not be precise because the amount of NaOH was too high and the solution went past the equivalent point. KHP was used in the titration because it has a mole to mole ratio with NaOH of one to one. It was also used because it is easy to measure the mass of KHP and dissolve it in H2O. The molarity of NaOH had to be found using a titration technique because it is not possible to measure the mass of NaOH because it will absorb H20 in the atmosphere and cause an error in the mass. Once the molarity of NaOH is found, it can be used...
Words: 753 - Pages: 4
...CHEM. 201, EXPERIMENT 4 TITRATION CURVES PROCEDURE: See the pre-lab report on page 15 of my laboratory notebook for an outline of the general procedure. The unknown acid number was 6553, and the concentration of NaOH used in the experiment was .09912 M. Also, three drops of phenolphthalein indicator were added to the initial titration and the titration curve. EXPERIMENTAL DATA: Initial Titration: * Volume of NaOH added at the endpoint was 29.8 mL Titration Curve: * Volume of NaOH added at the endpoint was 29.0 mL CALCULATED RESULTS: Acid concentration from first titration was .118M Ka from initial pH was 1.08x10^-5 Acid concentration from titration curve was .115M Titration | Volume of NaOH (mL) | pH | (base)/(acid) | pKa | Ka | 1/4 | 7.25 | 4.1 | 1/3 | 4.577 | 2.65x10^-5 | 1/2 | 14.5 | 4.6 | 1 | 4.6 | 2.55x10^-5 | 3/4 | 21.8 | 5.19 | 3 | 4.713 | 1.94x10^-5 | Average: | | | | 4.663 | 2.18x10^-15 | DISCUSSION: The purpose of the experiment was to titrate a weak acid of unknown concentration with a strong base, NaOH, and then utilizing an initial titration and titration curve to determine that acid concentration and Ka. After performing the initial titration of the acid concentration, we calculated it to be 0.118 M, with a Ka of 1.08x10^-5. On the other hand, when we performed the titration curve, it calculated an acid concentration of 0.115 M and a Ka of 2.18x10^-5. The results I obtained seemed reasonable...
Words: 545 - Pages: 3
...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...
Words: 2572 - Pages: 11
...12.097 Environmental Chemistry of Boston Harbor – IAP 2006 Lab 1: DETERMINATION OF DISSOLVED OXYGEN BY WINKLER TITRATION 1. Background Knowledge of the dissolved oxygen (O2) concentration in seawater is often necessary in environmental and marine science. It may be used by physical oceanographers to study water masses in the ocean. It provides the marine biologist with a means of measuring primary production - particularly in laboratory cultures. For the marine chemist, it provides a measure of the redox potential of the water column. The concentration of dissolved oxygen can be readily, and accurately, measured by the method originally developed by Winkler in 1888 (Ber. Deutsch Chem. Gos., 21, 2843). Dissolved oxygen can also be determined with precision using oxygen sensitive electrodes; such electrodes require frequent standardization with waters containing known concentrations of oxygen. They are particularly useful in polluted waters where oxygen concentrations may be quite high. In addition, their sensitivity can be exploited in environments with rapidly-changing oxygen concentrations. However, electrodes are less reliable when oxygen concentrations are very low. For these reasons, the Winkler titration is often employed for accurate determination of oxygen concentrations in aqueous samples. 2. Scope and field of application This procedure describes a method for the determination of dissolved oxygen in aqueous samples, expressed as mL O2 (L water)...
Words: 3465 - Pages: 14
...instruments __________________________________________________________________ Series A. Basic Quantitative Techniques Introductory Experiments (A-1) Experiment 1 Use of the Analytical Balance (page 727) (A-2) Experiment 2 Use of the Pipet and Buret and Statistical Analysis (page 729) Gravimetric Analysis (A-3) Experiment 3 Gravimetric Determination of Chloride (page 730) Volumetric Analysis Acid-Base Titrations Neutralization Titrations (A-4) Experiment 6 Determination of Replaceable Hydrogen in Acid by Titration with Sodium Hydroxide (page 736) (A-5) Experiment 7 Determination of Total Alkalinity of Soda Ash (page 738) Complexometric Titrations (A-6) Experiment 9 Determination of Water Hardness with EDTA (page 742) Precipitation Titrations (A-7) Experiment 11 Determination of Chloride in a Soluble Chloride: Fajan’s Method (page 745) Statistical Comparison of the results obtained from Exp 3 and Exp 11 Reduction-Oxidation Titrations...
Words: 606 - Pages: 3
...FISH 503 Advanced Limnology (University of Idaho, Moscow Idaho Cam pus) Oxygen Module Winkler titration lab Goal: To familiarize the participants with the Winkler titration of oxygen determination in water; understand principles of the underlying chemistry; to understand standardization procedures of chemical solutions; perform sodium thiosulfate standardization; perform Winkler titrations; examine experimenter error and intra-experimenter error. Examine “kits”. Outcomes: Ability to determine under what conditions Winkler chemistry is appropriate for determination of DO in water; ability to relate details of chemical reactions to and knowledge of indirect determinations; perform titrations and calculate titration standards, as well as mass of DO in samples; assess individual and among individual errors associated with method. General description: You have received a new O2 meter that the person giving to you ensures is ‘perfectly calibrated’ and ‘ready-to-go’. You are heading out on a one-shot chance to sample in the arctic, are you going to trust this person to have gotten it right. How do you check that your probe is actually giving you a believable number (yes does the light in the fridge really turn off when yo close the door?) You will find out in this lab how to check your sensor. Your tasks: 1) Familiarize yourself with the Winkler titration chemistry so you know what you are doing once you get your hands on the bottles and chemicals. 2) Standardize the Sodium thiosulfate...
Words: 3737 - Pages: 15
...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...
Words: 1292 - Pages: 6
...Experiment 1 Determination of the Acetic Acid Content of Vinegar. Goal: During this experiment you will gain experience in working with volumetric glassware, and gain knowledge on how to determine the uncertainties in the 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...
Words: 866 - Pages: 4
...The City University of New York (CUNY) LaGuardia Community College Course: Fundamentals of Chemistry II / Section: SCC202.1761 Professor Midas Student Name: Khushbu Patel Laboratory #7 – Determination of Ka for Weak Acids Laboratory Date: April 25, 2012 Objective Titrate a solution of unknown acid to the half-reacted point and use the pH of the solution at that point to determine ka for the unknown acid. Titrate a solution containing a weighed amount of solid unknown acid to the half-reacted point and use the PH of the solution at that point to determine Ka for the unknown Ka for the unknown acid. Introduction When an uncharged weak acid is added to water, a heterogeneous equilibrium forms in which aqueous acid molecules, HA(aq), react with liquid water to form aqueous hydronium ions and aqueous anions, A-(aq). The latter are produced when the acid molecules lose H+ ions to water. HA(aq) + H2O(l) H3O+(aq) + A-(aq) Water is not included in the acid-dissociation equilibrium expression because the [H2O] has no effect on the equilibrium. Acid + Base→ Salt+ Water Materials Used 10, 50 and 100-mL graduated cylinder 125-mL flask 3.5-mL of 6M NaOH Solution Distilled Water Glass stirring rod Beaker 50-mL of Unknown Acid Solution 25- or 50-mL buret Ringstand with buret clamp 10-mL pipet 125mL flask Phenolphthalein indicator Short range pH paper pH meter Procedure A. Determination of Ka for an Unknown Acid in Solution *...
Words: 960 - Pages: 4
...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...
Words: 2374 - Pages: 10
...CHEMISTRY 425 Analytical Chemistry II Dr. Petr Vanýsek, Instructor 07 POTENTIOMETRIC TITRATIONS OF CHLORIDE AND IODIDE In this experiment the concentrations of chloride and of iodide in an unknown solution will be determined by volumetric titration with standard solution of silver nitrate using potentiometric indication. The potential of a silver electrode immersed in the solution is measured with respect to a reference electrode. In this experiment a glass electrode will serve as a reference electrode, since the pH of the solution is invariant during the titration. The position of the titration curve with respect to the volume axis does not depend on any knowledge of the electrode potential for either the measuring electrode or the reference electrode. The data obtained also enable calculation of the solubility (solubility product) of AgCl and AgI. AgI (ca. Ksp = 1x10-16) precipitates first since it is less soluble than AgCl (ca. Ksp = 1x10-10). Silver chloride starts precipitation near the equivalence point of the iodide titration. The potential rise* of the iodide titration curve will level off at the point when the chloride starts precipitating, that is near the iodide equivalence point inflection. This will be followed by a typical S-shaped chloride potentiometric end point. The error in determining the iodide end point is small if it is taken at the point at which the potential levels off. [* Depending on the manner in which the reference and working electrodes are...
Words: 967 - Pages: 4
