...Stoichiometry Rebekah Muller Chemistry Lab 101-02 Instructor: Sam Stevenson Abstract: Stoichiometry is used to figure out how much potassium chlorate in a mixture of potassium chlorate and an inert substance (a substance that does not react chemically). By determining the mass of the product experimentally, the mass percent composition is calculated stoichometrically. After finding the mass percent composition, the final calculation to find is percent error (with the accepted value given). In this experiment, we use a solid that contains potassium chlorate as the reactant and then determine how much potassium chlorate was actually in the solid. To determine the amount of potassium chlorate, we heat up the solid on a Bunsen burner and measure how the solid as changed while the reaction was taking place. Objective: There are four objectives to this lab: to calculate the theoretical and percent yields, predict the effect of experimental error on percent yield, calculate the percent composition, and calculate the percent error. Introduction: The purpose of this lab is to determine the mass percent composition of potassium chlorate in an unknown substance by using Stoichiometry. Stoichiometry is the calculation of the quantities of chemical elements or compounds involved in chemical reactions. In this lab, the decomposition of the reaction would further the calculations of potassium chlorate in the mixture. Decomposition means the breaking down of...
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...Stoichiometry ________________________________________ Stoichiometry is simply the math behind chemistry. Given enough information, one can use stoichiometry to calculate masses, moles, and percents within a chemical equation. ________________________________________ ________________________________________ What is a Chemical Equation? In chemistry, we use symbols to represent the various chemicals. Success in chemistry depends upon developing a strong familiarity with these basic symbols. For example, the symbol "C"represents an atom of carbon, and "H" represents an atom of hydrogen. To represent a molecule of table salt, sodium chloride, we would use the notation "NaCl", where "Na" represents sodium and "Cl" represents chlorine. We call chlorine "chloride" in this case because of its connection to sodium. You should have reviewed naming schemes, or nomenclature, in earlier readings. A chemical equation is an expression of a chemical process. For example: AgNO3(aq) + NaCl(aq) ---> AgCl(s) + NaNO3(aq) In this equation, AgNO3 is mixed with NaCl. The equation shows that the reactants (AgNO3 and NaCl) react through some process (--->) to form the products (AgCl and NaNO3). Since they undergo a chemical process, they are changed fundamentally. Often chemical equations are written showing the state that each substance is in. The (s) sign means that the compound is a solid. The (l) sign means the substance is a liquid. The (aq) sign stands for aqueous in water and means...
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...CHAPTER 3 MASS RELATIONSHIPS IN CHEMICAL REACTIONS This chapter reviews the mole concept, balancing chemical equations, and stoichiometry. The topics covered in this chapter are: • Atomic mass and average atomic mass • A vogadro’ s number, mole, and molar mass • Percent composition calculations • Empirical and molecular formula determinations • Chemical equations, amount of reactant and product calculations • Limiting reagents and reaction yield calculations Take Note: It is absolutely essential that you master the mole concept to do well on the quantitative aspects of AP Chemistry!! When solving quantitative problems on the Free Response section of the AP exam, supporting work must be shown to receive credit. Using dimensional analysis is a very powerful technique in solving problems. Be sure to report your answer to the correct number of significant figures (see Chapter 1 in this review book). Atomic mass and average atomic mass Atomic mass is the mass of an atom in atomic mass units (amu). One amu is defined as 1/12 of one C-12 atom. The C-12 isotope has a mass of exactly 12.000 amu. The C-12 isotope provides the relative scale for the masses of the other elements. Average atomic mass is the value reported on the periodic table, which takes into account the various isotopes of an element and their respective frequencies. To calculate the average atomic mass of an element, add up the different masses of the isotopes (using amu) multiplied by each isotope’s abundance...
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...Powell Fabrication & Manufacturing Inc The Bleach Strength Test — A Chemical Test Method to Determine the Strength of Sodium Hypochlorite Last Update: March 30, 2001 Background The liquid sodium hypochlorite made by the Powell Continuous Bleach Manufacturing Plant or by other methods is produced as sodium hypochlorite (NaOCl) in the presence of excess caustic. Because consumers require differing solution concentrations, bleach manufacturers need to measure specific components of the product. Sodium hypochlorite (NaOCl), excess caustic (NaOH), and excess alkalinity (Na2CO3) are components in bleach that are routinely tested. Although this test procedure does not address heavy metals and sodium chlorate (NaClO3), a decomposition product, they should be tested at intermittent intervals and will require a qualified laboratory to perform these tests. Comparative Sample Analysis The test method below will provide accurate and repeatable results by the producer and consumer to ensure the product is meeting the desired specification. However, there are times when the strength of the sodium hypochlorite as tested by the manufacturer will differ from the consumer’s results. Many times these differences can be accounted for by the losses in shipping due to decomposition. However, it is difficult to know when the differences in test results are decomposition losses and when they are errors in test methods or procedures. In order for both the manufacturer...
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...“Chemistry is a science that deals with the composition, structure, and properties of substances and with the transformations that they undergo” (Merriam-Webster. 2011). Thus saying, Chemistry is a major influence on our lives on a daily basis. You find it by the air that you breathe in, the food that you eat, and every object that you can see or touch is a fundamental of Chemistry. Throughout this paper, I will describe why chemistry is important, what is beneficial, and what I found interesting. In order for me to purse my degree in Chemical Engineering, it was a must for me to take Chemistry 1411. First, it was a pre-requisite for the following Chemistry classes for me to take. Second, the basis of this class is a fundamental pertaining to my degree because they have to apply the principles of chemistry to design and operation of immense chemical manufacturing process. I chose this major because my grandfather inspired me from such a young age to be in this field. I can remember him doing all kinds of experiments in his office trying to test and discover things that really drew my interest to this major. My grandfather demonstrated the benefits of Chemistry and showed me how it is ever present in our every day life. He also taught me that Chemistry is always changing in our world around us and I want to be apart of this changing process and help the world benefit from Chemistry. I hope to see myself in a couple years being highly successful and enjoying working for a refinery...
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...AP Chemistry Summer Assignment Mr. Ronnenkamp Welcome to SPHS AP Chemistry!! You already have a background in chemistry from your General Chemistry class, but AP Chem is very different. Rather than memorizing how to do particular types of problems, you must really understand the chemistry and be able to apply it to different kinds of problems. AP Chemistry is a challenging course. To succeed, you must keep up with the assignments and be willing to spend time working through the material. Like all AP classes, AP Chem comes with a summer assignment. It is due the second day of class - August 25th - and will count as ½ of a test grade. ALL YOUR ANSWERS FOR THE SUMMER ASSIGNMENT SHOULD BE PUT ON ANOTHER SHEET OF PAPER!!!! We will then have a CLASS TEST on the SUMMER ASSIGNMENT ON 9/1/2015 (depending on schedule)!!! This class test will count as the second ½ of your first test grade. I check my e-mail frequently, so feel free to contact me if you are having problems doing the summer assignment. I can offer help via email. My e-mail address is: ronnenkampd@pcsb.org Please take the summer assignment seriously. Completing the summer assignment will allow you to enter AP Chemistry in August ready to succeed!!!! Each section of the summer assignment is referenced with web tutorials to help you if you have forgotten some of your General Chemistry, but feel free to use any good website. I will also be giving you access to an online textbook. ONLINE...
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...to those assigned as homework and at the end of each chapter in the textbook. (The Practice Examples are within the chapter, the problems appear at the end of the chapter.) Students must have their Temple photo ID card during lecture exams. TU-ID Numbers must be correctly and completely filled in on exams to ensure your score is properly recorded. Students are not allowed to have cell phones and other PDA devices on their persons while taking an exam. Cell phones/PDAs are to be placed in bags/backpacks which will be kept at the back of the lecture hall. Students may leave cell phones/PDAs on the front bench of the lecture hall. Students who are caught using cell phones/PDAs during an exam will be ejected from the exam and will receive a score of zero. This violation will be reported to the Dean and the Vice-Provost who will then take the appropriate disciplinary action. Only pens/pencils and scientific calculators (non-programmable and non-graphing) are allowed to be with students during exams. Students are not allowed to take an exam in a lecture section in which they are not registered. Chapter 4 – sections 4.1 – 4.8 Given a balanced chemical equation, you should be able to calculate grams (or moles) of a product (or reactant) given the grams (or moles) of another product (or reactant). Remember: grams A ( moles A ( moles B ( grams B (p. 118). Practice Example 4.1...
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...“The Project” An Unknown Ionic Compound in the Landfill Introduction Upon discovery of an unknown solid ionic compound in a landfill by the Chemistry 1146 laboratory group, precautions were immediately taken and rigorous experimentations were begun to determine the identity of the compound. Determining the identity of this compound was very crucial for the safety of the community. The chemical and physical properties of the compound could then be identified and environmental hazards addressed. Questions that needed to be answered in relation to this unknown compound included: Is it a risk to people living nearby? What if it gets in the water supply? Does it contaminate the air? Is it reactive? Over a three week time-span the chemists experimented with the unknown compound to report the findings back to the community. After the unknown compound was identified, the chemists studied its properties and confirmed the identity by synthesizing the compound in the lab and comparing it to the unknown. Experimental Week 1 After a sample of the unknown compound (#21) was retrieved, various experiments were carried out to determine the chemical formula. An anion analysis was first performed on the unknown compound. A solution of the unknown compound was prepared by taking a small amount of the solid on the end of a scoopula and dissolving it in 2 mL of distilled water (DI water) in a test tube. The compound was then tested for the sulfate ion by placing 1 mL of the solution in a test...
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...CHEMISTRY 101 Gases Chapter Five Omitted Sections 5.8 & 5.9 Suggested Problems 34, 45, 54, 60, 64, 67, 73, 75 & 82. Gas Properties 1. 2. 3. 4. Gases are highly compressible where liquids and solids are not. Gases occupy full volume of the container. Gases always form homogenous mixtures. In gases, there is spaces between gaseous molecules. 5. 1 Pressure Pressure = Force - N Area – m2 in Pascals (SI units) Pressure is measured using pressure gauges or diaphragm gauges. Atmospheric Pressure at sea level is 1 atm = 760 mm = 760 torr = 1.01 x 105 Pascals 5.2 The Gas Laws of Boyle, Charles, and Avogadro Boyle’s Law Measured pressure vs. volume. Pressure and Volume are indirectly proportional P = K 1/V At constant temperature, following relationship can be written as P1V1 = P2V2 P1V1 = P2V2 Charle’s Law Measured volume vs. temperature. Volume and temperature are directly proportional. V = K T where temperature is in Kelvin At constant pressure, following relationship can be written as V1 = V2 T1 T2 If you extrapolate the linear relationship between temp and volume down to volume equals to zero, you’ll get T = -273 oC also known as Absolute Zero equivalent to Zero Kelvin. The Effects of Increasing the Temperature of a Sample of Gas at Constant Pressure Avogadro’s Law Equal number of molecules occupy equal volumes at same temperature and pressure. V = K. n where n is number of moles At constant temperature and pressure, following...
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...Experiment 8: Redox: Analysis of the Oxidizing Capacity of Bleach PURPOSE In this experiment, you will show how redox reactions can be used to quantitatively determine the amount of oxidizing agent in liquid hypochlorite household bleach. There are two oxidation-reduction reactions for determining the oxidizing capacity of bleach. Initially an excess of iodide 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...
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...Tecnologia/Technology THE USE OF HYBRID VEHICLES AS A PROPOSAL FOR REDUCING CO2 EMISSIONS AND ITS CONTRIBUTION TO REDUCING GREENHOUSE GAS EMISSIONS C. A. R. de Carvalho, and W. Q. Lamas University of Taubate Postgraduate Programme in Mechanical Engineering Rua Daniel Danelli, s/n – Jd. Morumbi 12060-440, Taubate, SP, Brazil carlosalfredo.carvalho@hotmail.com, wendell@unitau.br ABSTRACT The problems related to energy consumption and pollutant emissions for the transport sector represent a major global concern regarding climate changes caused by greenhouse gases, directly related to the increased level of gas emissions from fossil fuels , the main one being carbon dioxide. One way to minimize this problem is through the introduction of new technologies. Hybrid cars are one of the new technology options that has the main advantage of reducing fuel consumption and therefore reducing the amount of CO2 in the atmosphere. This paper gives an introduction to hybrid vehicles, with the aim of presenting their main advantages and evaluate their impact on emissions of CO2 in the Brazilian fleet, compared to conventional vehicles. Keywords: CO2 emissions, fuel consumption, hybrid vehicles. NOMENCLATURE AR ER PEF N average round by a vehicle, km/year emission rate of CO2 per vehicle, t/year pollutant emission factor, g/km number of vehicles in the year INTRODUCTION Climate change and the increase in greenhouse gases are the main topics of discussion today in global discussions...
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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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...in applied areas of science and technology at tertiary level. Therefore, at this stage, there is a need to provide learners with sufficient conceptual background of Chemistry, which will make them competent to meet the challenges of academic and professional courses after the higher secondary stage. National Curriculum Framework for School Education – 2005 recommends a disciplinary approach with appropriate rigour and depth with the care that syllabus is not heavy and at the same time it is comparable to the international level. It emphasizes a coherent focus on important ideas within the discipline that are properly sequenced to optimize learning. It recommends that theoretical component of Higher Secondary Science should emphasize on problem solving methods and the awareness of Syllabus for Secondary and Higher Secondary Levels 22 historical development of key concepts of science be judiciously integrated into content. The present exercise of syllabus development in Chemistry at Higher Secondary Stage is based on this framework. Salient features of the present syllabus are thus: • Some background of Chemistry from secondary stage is assumed; however, no specific knowledge of topics in Chemistry is pre-supposed. • The course is self-contained and broadly covers fundamental concepts of Chemistry. • Attempt has been made to see discipline of Chemistry does not remain only the science of facts but becomes related to...
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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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...ANATOMY AND PHYSIOLOGY- 2013 Draft v4 7-3-12 1. DESCRIPTION: Understand the anatomy and physiology of the nervous, excretory and digestive system. A TEAM OF UP TO: 2 APPROXIMATE TIME: 50 Minutes 2. EVENT PARAMETERS: Each team may bring only one 8.5" x II" two-sided page of notes that contain information in any form from any source and up to 2 non-programmable, non-graphing calculators. 3. THE COMPETITION: Students should know the basic anatomy and physiology of the nervous, excretory and digestive systems and how aging and specific diseases affect them. Process skills expected may include data collection, making observations, inferences, predictions, calculations, analyses and conclusions. The test may include various formats (e. g., timed stations, written test, PowerPoint slides, anatomical specimens, etc.) for the following topics: a. DIGESTIVE SYSTEM - All levels should know: 1. Functions ofthe digestive system 11. Basic anatomy of the component parts of the alimentary canal and accessory organs of digestion iii. Anatomy of the four layers ofthe wall of the alimentary canal IV. Comparison of the lining of the esophagus, stomach, small intestine and large intestine v. Compare and contrast mechanical and chemical digestion vi. Physiology of chemical digestion of proteins, fats and carbohydrates vii. The effects of exercise on the digestive system viii. The diseases on each level from the cell to the whole person as listed: stomach & duodenal ulcers, cancers of the digestive...
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