...Title Acid-base titration: Determination of the percentages (%) of sodium carbonate (Na2CO3) and sodium hydroxide (NaOH) in a mixture Objective To determine the respective weight per cent of sodium carbonate and sodium hydroxide in a mixture by acid-base titration. Result and calculation Part A Titration 1 Titration number 1 2 3 Initial volume of burette( cm3) 5.10 2.70 9.70 Final volume of burette (cm3) 34.40 31.80 39.20 Total volume of HCl used (cm3) 29.30 29.10 29.50 Average volume of HCl required for titration =(29.30+29.10+29.50)/3 cm3 = 29.30 cm3 Titration 2 Titration number 1 2 3 Initial volume of burette( cm3) 4.50 14.00 2.70 Final volume of burette (cm3) 25.00 21.70 22.80 Total volume of HCl used (cm3) 20.50 20.30 20.10 Average volume of HCl required for titration =(20.50+20.30+20.10)/3 cm3 = 20.30 cm3 Part B Titration number Rough 1 2 3 Initial volume of burette( cm3) 4.9 4.80 3.60 2.20 Final volume of burette (cm3) 28.3 28.90 27.70 26.20 Total volume of HCl used until phenolphthalein decolourised (cm3) , x 23.4 24.10 24.10 24.00 Initial volume of burette after adding methyl orange indicator ( cm3) 28.3 28.90 27.70 26.20 Final volume of burette (cm3) 34.1 33.40 32.10 30.70 Total volume of HCl used until phenolphthalein decolourised (cm3) , y 5.8 4.50 4.40 4.50 Average volume of HCl required to react with Na2CO3 (2y) =2(4.50+4.40+4.50)/3 cm3 = 2(4.4667) cm3 ...
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...Titrations Revisited By Drew Rutherford Concordia College Introduction The first experiment today will be the titration of acetic acid in vinegar. Vinegar is a solution of acetic acid, an organic acid of formula CH3COOH (MW = 60.0526 g/mole). In order to be sold as vinegar, it needs to meet the FDA’s guideline of 5.00% acetic acid by mass. Knowing that the density of vinegar is 1.04 g/mL and analyzing this solution by titration, chemists can determine the mass percentage of acetic acid in a sample of vinegar. The titration reaction is given below: CH3COOH + NaOH ( CH3COONa + H2O Reaction 1 A customer has purchased a vinegar solution at a local thrift store at a 20% discount and he believes that the sample of vinegar he has purchased does not meet FDA regulations. He is suing the thrift store for the $0.36 he feels that he has been cheated out of. The court has asked you to analyze the sample and render your verdict. Does this sample conform to the FDA guideline? If 2.00 mL of the thrift store vinegar required 9.73 mL of 0.150 M NaOH to reach the endpoint, then 0.00877 g of acetic acid was present. 9.73 mL NaOH x 1 liter NaOH x 0.150 mole NaOH x 1 mole CH3COOH x 60.0526 g CH3COOH 1000 mL 1 liter 1 moles NaOH 1 mole CH3COOH = 0.0876 grams CH3COOH in sample 2.00 mL vinegar x 1.04 g vinegar = 2.08 g vinegar 1 mL 0.0876 g CH3COOH x 100 = 4.21 % CH3COOH by mass 2...
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...Acid-Base Titration: Determination of the Percentages (%) of Sodium Carbonate (Na2Co3) and Sodium Hydroxide (Naoh) in a Mixture Title Acid-base titration: Determination of the percentages (%) of sodium carbonate (Na2CO3) and sodium hydroxide (NaOH) in a mixture Objective To determine the respective weight per cent of sodium carbonate and sodium hydroxide in a mixture by acid-base titration. Result and calculation Part A Titration 1 Titration number 1 2 3 Initial volume of burette( cm3) 5.10 2.70 9.70 Final volume of burette (cm3) 34.40 31.80 39.20 Total volume of HCl used (cm3) 29.30 29.10 29.50 Average volume of HCl required for titration =(29.30+29.10+29.50)/3 cm3 = 29.30 cm3 Titration 2 Titration number 1 2 3 Initial volume of burette( cm3) 4.50 14.00 2.70 Final volume of burette (cm3) 25.00 21.70 22.80 Total volume of HCl used (cm3) 20.50 20.30 20.10 Average volume of HCl required for titration =(20.50+20.30+20.10)/3 cm3 = 20.30 cm3 Part B Titration number Rough 1 2 3 Initial volume of burette( cm3) 4.9 4.80 3.60 2.20 Final volume of burette (cm3) 28.3 28.90 27.70 26.20 Total volume of HCl used until phenolphthalein decolourised (cm3) , x 23.4 24.10 24.10 24.00 Initial volume of burette after adding methyl orange indicator ( cm3) 28.3 28.90 27.70 26.20 Final volume of burette (cm3) 34.1 33.40 32.10 30.70 Total volume of HCl used until phenolphthalein decolourised (cm3) , y 5...
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...solution and standardization of hydrochloric acid To prepare a standard solution of sodium carbonate and use it to standardize a given solution of dilute hydrochloric acid. Anhydrous sodium carbonate is a suitable chemical for preparing a standard solution (as a primary standard). The molarity of the given hydrochloric acid can be found by titrating it against the standard sodium carbonate solution prepared. The equation for the complete neutralization of sodium carbonate with dilute hydrochloric acid is Na2CO3(aq) + 2HCl(aq) → 2NaCl(aq) + CO2(g) + H2O(l) The end-point is marked by using methyl orange as indicator. Introduction : Chemicals : Apparatus : Procedure : solid sodium carbonate, 0.1 M hydrochloric acid 1. 2. 3. 4. 5. 6. 7. 8. Weight out about 1.3 g of anhydrous 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...
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...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 41 Quantifying errors 41 Absolute uncertainties and percentage uncertainties 42 Combining uncertainties 43 Some ‘forgotten’ uncertainties 46 Experiments 53 Experiment 1A: Preparation of a standard solution of 0.1 mol l–1 oxalic acid 53 Experiment 1B: Standardisation of approximately 0.1 mol l–1 sodium hydroxide 55 Experiment 1C: Determination of the ethanoic acid...
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...sources of traditional materials such as those from the petrochemical industry. As the fossil organic reserves dwindle, new sources of the organic chemicals presently used have to be found. In addition, chemists are continually searching for compounds to be used in the design and production of new materials to replace those that have been deemed no longer satisfactory for needs. This module increases students’ understanding of the implications of chemistry for society and the environment and the current issues, research and developments in chemistry. 1.1 Construct word and balanced formulae equations of all chemical reactions as they are encountered in this module: • Acid reactions: o acid (aq) + base (aq) salt (aq) + water (l) o acid (aq) + active metal (s) salt (aq) + hydrogen (g) o acid (aq) + metal carbonate (s) salt (aq) + water (l) + carbon dioxide (g) • Cracking of long chain alkanes (e.g. decane) to give a shorter chain alkene & alkane o Thermal cracking (heated with steam in absence of O2 to 750-900°C) Initiation: C10H22 2C5H11· Propagation: C5H11· C3H7· + C2H4 Termination: 2C3H7· C6H14 o Catalytic cracking zeolite (heated in absence of O2 to 500°C)...
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...CALCULATION EXERCICES To the LABORATORY EXPERIMENTS IN MEDICAL CHEMISTRY Edited by: Zoltán Matus Compiled by: Péter Jakus László Márk Anikó Takátsy Pécs, 2007 Table of content: Introduction 3 1. Stoichiometry I. Balancing equations 4 2. Stoichiometry II. Calculation exercises 9 3. The gaseous state 13 4. Concentrations of solutions 17 5. Calculations connected to titrimetry 28 6. Electrolytic dissociation 33 7. Dilute solutions 38 8. Hydrogen ion concentration, pH, buffers 44 9. Heterogeneous equilibria. Crystallisation, solubility product, partition coefficient 55 10. Thermochemistry 64 11. Electrochemistry 67 2 INTRODUCTION The chapter is devoted to helping the students practice the most important topics of General Chemistry. The order of the sections follows the schedule of the lectures and seminars, and their volume indicates the importance of the topic. Each section begins with a few solved problems. They represent the minimum requirement at the exam. The worked-out solutions are not the only ones. For an easier self-checking, the numerical results of the unsolved calculation exercises are given in parentheses after each question. Sources: 1.) Laboratory experiments in medical chemistry, ed. György Oszbach, Pécs, 1998. 2.) Villányi Attila: Ötösöm lesz kémiából, (6. ed.) Mőszaki Könyvkiadó, Budapest., 1999 3.) Charles E. Mortimer...
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...a gas X contains Z molecules at 150C and 75mmHg. How many molecules will 25cm3 of another gas Y contain at the same temperature and pressure? (A) 2Y (B) 2Z (C) Z (D) Y 4. What mass of water is produced when 8.0g of hydrogen reacts with excess oxygen? (A) 36.0g (B) 8.0g (C) 72.0g (D) 16.0g [H = 1, O = 16] 5. A particle that contains 9 protons, 10 neutrons and 10 electrons is a (A) negative ion (B) positive ion (C) neutral atom of a non metal (D) neutral atom of a metal 6. Cancerous growth are cured by exposure to (A) γ -rays (B) β -rays (C) α -rays (D) x-rays 7. An oxide XO2 has a vapour density of 32. What is the atomic mass of X (A) 32 (B) 20 (C) 14 (D) 12 [O = 16] 8. Milikan’s contribution to the development of atomic theory is the determination of (A) charge on electron (B) positive rays (C) charge to mass ratio (D) cathode rays 9. Four elements W, X, Y, and Z have atomic numbers 2, 6, 16 and 20 respectively. Which of these elements is a metal? (A) X (B) W (C) Z (D) Y 10. An element X with relative atomic mass 16.2 contains two isotopes 16X 8 with relative abundance of 90% and X m8 with relative abundance of 10%. The value of m is (A) 16 (B) 18 (C) 12 (D) 14 11. + The diagram above represents the formation of (A) a metallic bond (B) an electrovalent bond (C) a covalent bond (D) a coordinate bond 12. Which of the following statement is correct about the average kinetic energy of the molecules of a gas? 2 (A) It increases with increase in pressure (B) It increases at constant...
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...AS/A Level GCE GCE Chemistry A OCR Advanced Subsidiary GCE in Chemistry A H034 OCR Advanced GCE in Chemistry A H434 Vertical black lines indicate a significant change to the previous printed version. © OCR 2008 version 2 – February 2008 QAN 500/2425/5 QAN 500/2347/0 Contents 1 About these Qualifications 1.1 1.2 1.3 1.4 1.5 The Three-Unit AS The Six-Unit Advanced GCE Qualification Titles and Levels Aims Prior Learning/Attainment 4 4 4 5 5 5 2 Summary of Content 2.1 2.2 AS Units A2 Units 6 6 7 3 Unit Content 3.1 3.2 3.3 3.4 3.5 3.6 AS Unit F321: Atoms, Bonds and Groups AS Unit F322: Chains, Energy and Resources AS Unit F323: Practical Skills in Chemistry 1 A2 Unit F324: Rings, Polymers and Analysis A2 Unit F325: Equilibria, Energetics and Elements A2 Unit F326: Practical Skills in Chemistry 2 8 8 20 38 40 51 62 4 Schemes of Assessment 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 AS GCE Scheme of Assessment Advanced GCE Scheme of Assessment Unit Order Unit Options (at AS/A2) Synoptic Assessment (A Level GCE) Assessment Availability Assessment Objectives Quality of Written Communication 64 64 65 66 66 66 67 67 68 5 Technical Information 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 Making Unit Entries Making Qualification Entries Grading Result Enquiries and Appeals Shelf-life of Units Unit and Qualification Re-sits Guided Learning Hours Code of Practice/Subject Criteria/Common Criteria Requirements Arrangements for Candidates with Particular...
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...------------------------------------------------- March 2013 APPROVAL SHEET This thesis entitled “Utilization of Characterized Activated Carbon Prepared from Corn Cobs in Sugar Decolorization”, prepared by Dyle Angellowe B. Mapagu, Aurilyn A. Ramirez and Roxanne L. Soriano, in partial fulfilment of the requirements for the degree Bachelor of Science in Chemical Engineering, is hereby recommended for oral examination. Approved by the Tribunal on Oral Examination with a grade of _________. Engr. Ma. Haidee A. Mabborang Member Engr. Monico U. Tenedor Member Engr. Marianne DC. Calica Member Engr. Caesar P. Llapitan Chairman Accepted in partial fulfilment of the requirements for the degree Bachelor of Science in Chemical Engineering. Engr. Ernesto D. Marallag Dean, College of Engineering ACKNOWLEDGEMENT We, the authors, convey our gratefulness and appreciation to the people who have given valuable assistance in the completion of this study. To Engr. Policarpio Mabborang, Jr. for providing a perceptive and logical evaluation of our research, for his corrections and suggestions in the improvement of the study, and for his patience towards us; To Engr. Caesar Llapitan, Engr. Marianne Calica, Engr. Monico Tenedor, and Engr. Ma. Haidee Mabborang, who served as our panelists in the defense, pointed out mistakes and gave good suggestions in revising our thesis; To Engr. Gina Consigna, head of the Feed Laboratory...
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...Chemistry Modern Analytical Chemistry David Harvey DePauw University Boston Burr Ridge, IL Dubuque, IA Madison, WI New York San Francisco St. Louis Bangkok Bogotá Caracas Lisbon London Madrid Mexico City Milan New Delhi Seoul Singapore Sydney Taipei Toronto McGraw-Hill Higher Education A Division of The McGraw-Hill Companies MODERN ANALYTICAL CHEMISTRY Copyright © 2000 by The McGraw-Hill Companies, Inc. All rights reserved. Printed in the United States of America. Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a data base or retrieval system, without the prior written permission of the publisher. This book is printed on acid-free paper. 1 2 3 4 5 6 7 8 9 0 KGP/KGP 0 9 8 7 6 5 4 3 2 1 0 ISBN 0–07–237547–7 Vice president and editorial director: Kevin T. Kane Publisher: James M. Smith Sponsoring editor: Kent A. Peterson Editorial assistant: Jennifer L. Bensink Developmental editor: Shirley R. Oberbroeckling Senior marketing manager: Martin J. Lange Senior project manager: Jayne Klein Production supervisor: Laura Fuller Coordinator of freelance design: Michelle D. Whitaker Senior photo research coordinator: Lori Hancock Senior supplement coordinator: Audrey A. Reiter Compositor: Shepherd, Inc. Typeface: 10/12 Minion Printer: Quebecor Printing Book Group/Kingsport Freelance cover/interior designer: Elise Lansdon Cover image: © George Diebold/The...
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