...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...
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...London School of Engineering and Materials Science Laboratory report writing instructions DEN101 - Fluid Mechanics 1 Flow Rate Measurement Experiment A. Student Student Number: 1234567 Version 2.0, 27 November 2010 Template for Word 97-2003 Abstract This document explains what is expected in your Fluids 1 lab report. The sections that should be covered are outlined and a structure you could follow is proposed. Detailed advice on how to edit the report is given. The document concludes with the marking criteria for this lab report. Table of Contents Abstract 2 1. Introduction 3 1.1. Writing 3 1.2. Editing and formatting 3 1.3. Content of the introduction 4 2. Background and theory 4 3. Apparatus 4 4. Test 4 5. Experimental procedure 4 6. Results 5 7. Discussion 5 8. Conclusions 5 9. References 5 10. Appendix A: Marking criteria 6 Introduction Before starting to write a report, you should think about what is your audience. Am I writing for colleagues who want a lot of detail how it is done, or am I writing for my boss who just wants an executive summary as he has no time for details? In general, there is not a single type of audience and we have to make our writing suitable for the detailed read, as well as the fast perusal. To understand what is required from you in this report, please have a look at the marking criteria in the Appendix. 1 Writing To limit...
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...SCIN131 Lesson 6 Lab: Titrations and Natural Acid/Base Indicators Begin by viewing the following Thinkwell videos 15.1.7 CIA Demonstration: Titrations 11.2.2 CIA Demonstration: Natural Acid-Base Indicators (NOTE: The second video is sort of a supplement to the first, and shows how this applies to your daily life. Feel free to try some of the things listed in the video, but be sure to report back to the class regarding the results of your experiments!) After you watch the above video, answer the questions below in sufficient detail: (a) (1 pts.) In YOUR OWN WORDS, what is a titration? What type of reaction is it? Be detailed and specific...
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...EXPERIMENT 2 Sampling Errors Introduction Representative sampling of materials prior to chemical analysis has been recognized to be as important as the subsequent steps in the analysis. The overall variance of an analysis has several components – including sampling, sample extraction and preparation, and instrumental random errors: s2total = s2sampling + s2prep + s2instr If any one of the variances is significantly larger than the others, there is little point in trying to reduce the others, since the dominant source of error will determine the overall uncertainty. For some analytical problems, the sampling variance can dominate the precision of the entire analysis since real-world samples are often difficult to sample in such a way that a portion for analysis is representative of the whole. Many sampling problems arise from inhomogeneities in almost any sample, including gases, liquids as well as solids mixtures. The sampling of solid mixtures is straightforward to explore, and represents an important area for analytical chemists as well as for compounding chemists who prepare pharmaceuticals and composite materials. Origin of Sampling Variance: [Adapted from “Quantitative Chemical Analysis”, Daniel Harris, 7th edition.] Where does sampling variance come from? Consider a randomized mixture of two kinds of particles. The theory of probability allows one to estimate the likelihood that a sample drawn from the mixture has the same composition...
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...Laboratory Report I. Title: We will use titration to determine the purity of synthesized aspirin. In doing so, we will measure the volume of the aspirin accurately. Then, we will use NaOH to titrate the aspirin solution. The analysis of this titration data will allow use to calculate the percentage of acid in the original solution. We will then compare these values to those expected is the sample was made from pure acetylsalicylic acid. The difference from this will come from impurities. II. Authors: Katie Warren, Annie Haman & Jacob Brotherton III. Abstract: The mass of acetylsalicylic acid was determined using a analytical balance. Sodium hydroxide (NaOH) was added to the “white powder” to titrate to produce a persistent, pale pin endpoint. The percentage purity of aspirin was found to be 74.88%. IV. Pre-lab assignment: OMIT V. Procedure: Refer to the lab handout for procedure VI. Chemical Reactions: Aspirin Synthesis: NaOH (aq) + KHC8H4O4 (aq) NaKC8H4O4 (aq) + H2O (I) Aspirin Titration: HA (aq) + NaOH (aq) H2O (I) + NaA (aq) VII. Experimental/Calculated Data: Table 1: Mass of Aspirin | Trial 1 | Mass Watch Glass + White Powder (g) | 38.2625 | Mass of Empty Watch Glass (g) | 37.72 | Mass of White Powder | .5425 | VIII. Calculations: IX. Results and Discussion: X. Conclusions: We have experimentally determined and achieved the percent purity of the aspirin we had previously made. The volume of the solvent that dissolved...
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...Enzyme Catalysis: Lab Report Introduction: In the lab there were 4 parts (A, B, C, D). Each part having a different reaction among it, an example of this reaction could be lab A when the catalysis was tested for activity. The reaction was to support the affect catalysis had on the hydrogen peroxide. This was a fizzing and bubbling state supporting a reaction was occurring. So one can infer that if enzyme catalysis brakes down hydrogen peroxide, then an abandons of catalysis would break down more hydrogen peroxide upon a quicker rate. Materials and methods: Part A: hydrogen peroxide, catalysis. After taking 10ml of H2O2 and mixing it with 1ml of catalysis for 30 seconds. After the reaction the data was recorded. Part B: H2H2, H4SO4, KMnO4 H2O. In the reaction an observation of 10ml of H2O2 in a 60ml container, next 1ml of distilled water is transferred, then 10ml H2SO4 is moved to a cup labeled baseline, finally 5ml of the solution is moved from baseline to titration and is titrated. Lastly the data is recorded. Part C: H2O2 (overnight), H2SO4, KMnO4. Basically the same reaction that occurred in part B was duplicated, but with an overnight solution of H2O2. It was in a baseline and the transferred to titration and then data was recorded. Part D: H2O2, H2SO4, KMnO4. With 60ml cups labeled 10sec, 30sec, 60sec,120sec, and 180sec catalysis was put to a decomposes test. 1ml of catalysis was transferred to a cup and then was swirled. Finally H2SO4 was added to stop the enzyme...
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...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...
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...ions are added to a bleach solution. The iodide ions are oxidized to iodine after the solution has been acidified. Starch is added to the resulting iodine solution as an indicator. The solution is then titrated with sodium thiosulfate until the color of the solution changes indicating the endpoint of the reaction. Data collected from the titrations will be used to calculate the mass of the sodium hypochlorite in an unknown solution of bleach. Given the original mass of the unknown solution and the calculated mass of the sodium hypochlorite in the unknown solution, the percent by mass of the sodium hypochlorite can be determined. The oxidizing capacity of the unknown bleach is effectively the percent by mass of the sodium hypochlorite in the unknown bleach sample. OJECTIVES 1) Titration of a sample of bleach with thiosulfate. 2) Determining the end point of the titration with starch indicator. 3) To determine oxidizing capacity of bleach by determining the percentage by mass of the bleach that is sodium hypochlorite. 4) Balance and summarize the two redox reactions to determine the overall chemical reaction that occurs during the titration. PRINCIPLES Oxidizing Capacity of Bleach The effectiveness of a bleach to whiten and remove stains in white clothing is related to the oxidizing (bleaching) strength of an oxidizing agent, such as OCl−, which is found in common household bleaches. The hypochlorite ion is generally present as a sodium salt, NaOCl, or a calcium salt, Ca(ClO)2...
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...Experiment 8 Lab Report Analysis of Oxidizing Capacity of Bleach The goal of this lab is to perform a titration of a sample of bleach with thiosulfate, figuring the end point with a starch indicator. We will determine the percent mass of sodium hypochlorite in bleach by using the volume of sodium thiosulfate needed to reach the end point. This value represents the oxidizing capacity of the unknown bleach. At the end, we will create two redox reactions to determine the overall chemical reaction that occurs during this process. I think that my oxidizing capacity will be 5.0g. Most bleach contains salts with the hypochlorite ion, the oxidizing agent that removes stains and whitens them. The hypochlorite ion usually comes in the form of sodium hypochlorite, NaOCl, or calcium hypochlorite. The two oxidation reduction reactions that occur during this experiment are first the oxidation of iodide to iodine, I2(aq), by the hypochlorite ion and then making the aqueous iodine reduce back to iodide by titrating it with sodium thiosulfate. The overall stoichiometry of the reaction is one mole of hypochlorous acid, formed by placing the sodium hypochlorite into acidic solution, plus two moles of the thiosulfate ion plus hydrogen ions from the solution yielding one mole of chlorite anions, one mole of the tetrasulfur hexoxide anion and one mole of liquid water. We began the titration of aqueous iodine by adding .05M sodium thiosulfate until the brown colored solution began to turn a...
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...Volumetric and Vinegar Analysis Abstract This report presents volumetric and vinegar analysis. In volumetric analysis three trials of a solution. The volumetric analysis was obtained through titration, and chemical analysis, which allowed the molar concentration of a strong acid to be assessed in a standardized solution. The Average molar concentration of NaOH is approximately 0.279mol/L. Vinegar analysis was conducted with the help of three trials to determine the percent by mass of acetic acid in vinegar instead of a standardized solution. The unknown vinegar being utilized was “Shaggy”. The average percent by mass of CH3COOH “Shaggy” is 1.41%. According to “Laboratory Manual for Principles of General Chemistry”, volumetric analysis is a chemical analysis that is performed primarily with the aid of volumetric glassware. For this procedure, a known quantity or carefully measured amount of one substance reacts with a to-be-determined amount of another substance with the reaction occurring in an aqueous solution. This is conducted by a titration procedure. A burette dispenses a liquid called the titrant to a receiving flask containing the analyte (Beran, 133). The reaction is known to be completed when amounts corresponding to the mole ratio of the balanced equation is reached – this is referred to as the stoichiometric point. In the lab, standardization of a sodium hydroxide solution was performed, thus creating the secondary standard solution (Beran, 135)...
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...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...
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...regions in the document below. Question #1 Antacid Volume NaOH used in back-titration (mL) Volume NaOH used in back-titration (L) Moles NaOH used in back-titration Maalox 24.1 mL Tums 22.4 mL Mylanta 20.0 mL CVS 19.9 mL Rennies 24.4 mL Based on the values you calculated above, which antacid is the strongest / weakest on a single-dose basis? Please explain. Question #2 Antacid Moles HCl neutralized by the antacid Mass of one dose Moles/gram for one dose Maalox 20.0 g Tums 21.0 g Mylanta 18.0 g CVS 18.3 g Rennies 17.5 g Based on the values you calculated above, which antacid is the strongest / weakest on a by-weight (mass) basis? Please explain. Question #3 What might you have used in the above experiment in order to see a visible color change in the solution? At what pH would the solution have been neutral? Question #4 If you had walked into the lab, only to discover that you only had 0.1 M sulfuric acid available to run you tests, how might this have affected your calculations? Why? Question #5 Balance the following reaction. Al(OH)3 + HCl AlCl3 + H2O Question #6 FDA major findings report and summary. ...
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...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 *...
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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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...In the 4th quarter of 9th grade science we continued our study of chemistry with a focus on chemical formulas, chemical reactions, and stoichiometry. Formative assessments included practice questions on how to write proper names and formulas for chemical compounds, balancing equations, converting between chemical units, and titration problems. The lab experiments for the quarter consisted of a freezing point experiment, chemical flame test comparison, the activity series of four metals, production of hydrogen, and the titration of an unknown concentration of acid. Summative assessments for the quarter were an evaluation of the freezing point experiment, written exploration of the flame test experiment, and two unit exams on chemistry topics. In 10th grade students will study science topics related to biology, environmental science, and some...
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