ANALYTICAL CHEMISTRY for TECHNOLOGISTS Part 1

Ministry of Education and Science of Ukraine Kyiv National University of Technologies and Design T. M. Derkach ANALYTICAL CHEMISTRY FOR TECHNOLOGISTS Part 1 KNUTD Textbook Series for International Training Programmes Kyiv 2020 Dedicated to the 90th anniversary of Kyiv National University of Technologies and Design 2 T. M. Derkach Analytical Chemistry for Technologists Part 1: Sections 1-9 It is recommended by the Academic Council of the Kyiv National University of Technology and Design as lecture notes for students of higher education in the fields of chemical technology & engineering, biotechnology & bioengineering, and pharmacy & industrial pharmacy UDC 543(075.8)=111 D45 Reviewers: A. B. Vishnikin, Professor, Doctor of Science in Chemistry, Head of the Analytical Chemistry Department at Olesj Honchar Dnipro National University; M. V. Nikolenko, Professor, Doctor of Science in Chemistry, Head of the Department of analytical chemistry and chemical technology of food additives and cosmetics at Ukrainian State University of Chemical Technology, Dnipro; L. A. Raskola, PhD in Chemistry, Deputy Dean for Educational Work, Faculty of Chemistry and Pharmacy at Odessa I.I. Mechnikov National University It is recommended by the Academic Council of the Kyiv National University of Technology and Design (Minutes No 2 dated September 23, 2020) Derkach T. M. D45 Analytical Chemistry for Technologists: lecture notes for students of technological specialities. Part 1: Sections 1-9. Kyiv : KNUTD, 2020. 198 p. ISBN 978-617-7506-64-4 The book presents the basic concepts of analytical chemistry, such as qualitative and quantitative chemical analysis, sampling and sample preparation, statistical data processing, separation methods. Modern physicochemical methods of analysis are considered. The theoretical bases of methods are stated, conditions and their branches are specified practical application. The control questions and tasks presented at the end of each section will help to consolidate the studied material. The book is intended for undergraduate students majoring in chemical technologies & engineering, biotechnology & bioengineering, and pharmacy & industrial pharmacy. The lecture notes consist of two parts. The first part includes Sections 1-9 and covers introductory topics, equations and equilibrium, classic methods of chemical analysis. The second part includes Sections 10-18 and covers instrumental methods. UDC 543(075.8)=111 ISBN 978-617-7506-64-4 © T. M. Derkach, 2020 © KNUTD Publishing Department, 2020 2 Content Section 1: Common Analytical Problems .......................................................................... 5 Section 2: Treatment of Analytical Data .......................................................................... 36 Section 3: Sample Collection, Handling and Preparation ................................................ 61 Section 4: Chemical Equilibrium ...................................................................................... 82 Section 5: Concentration. Preparing Solutions .............................................................. 104 Section 6: Qualitative Chemical Analysis ...................................................................... 121 Section 7: Basics of Titration. Titrimetric Methods ........................................................ 130 Section 8: Complexometric and Redox Titration ........................................................... 149 Section 9: Gravimetric Analyses ................................................................................... 169 Appendices ................................................................................................................... 178 o A. Dissociation constants and pKa values for acids at 25 C ..................................... 178 o B. Dissociation constants and pKb values for bases at 25 C .................................... 178 o C. Solubility-product constants (Ksp) for compounds at 25 C ................................... 179 D. Standard reduction potentials at 25oC ................................................................. 181 E. Properties of water ............................................................................................... 183 F. Physical constants ............................................................................................... 184 G. Formation constants for complex ions in aqueous solutions ............................... 184 H. Densities of acids, alkalis and some other substances ........................................ 185 Bibliography .................................................................................................................. 195 3 Introduction Analytical chemistry is a branch of chemistry that deals with the study of theory and practice of methods used to determine the composition of matter. Analytical chemistry is often described as a field of chemistry that is responsible for characterizing the composition of a substance, both qualitatively and quantitatively. However, analytical chemistry and chemical analysis are not the same. The difference between analytical chemistry and chemical analysis is that analyst chemists work to improve and expand established analytical methods. The characteristic detail of analytical chemistry is not to perform routine analysis on a routine sample, which is more appropriately called chemical analysis. The meaning of the analytical chemistry is to improve established methods, to expand them to new types of samples and to develop new analytical methods for measuring chemical phenomena. Forty to fifty years ago, the chemical analysis focused on three main areas: qualitative determination; quantitative determination using "classical" methods of titrimetry and gravimetry; structural analysis, which required time-consuming procedures and calculations. Today, chemists have instrumental methods, automated systems, and computers that make analytical measurements easier, faster, and more accurate. However, the chemist has to have profound understanding principles, areas of practical application and limitations of each method to work without mistakes. Reviews of daily operations of many industrial and other analytical laboratories in the UK, Europe, Japan and the US have identified the most methods widely used. The textbook describes the techniques and methods commonly used by most analytical laboratories today. The textbook is written as lectures-presentations, which gradually reveal the analytical process. Regardless of the area where the need for analysis arises, the chemist needs to answer the following questions: How should a representative sample be obtained? How much material is available for analysis and how many samples should be taken? What should be determined? With what accuracy? What components are in the sample? Will they have interferences? What tools should be used? How reliable will the data be? The answers to these questions and related topics are discussed in Sections 1-3. Statistical methods of processing the results are given somewhat simplified, but enough to obtain reliable results and use them to assess the correctness of the proposed analysis methods. The following lectures-presentations contain a description of the principles, tools and application of analytical methods. The lecture notes consist of two parts. The first part includes Sections 1-9 and covers introductory topics, equations and equilibrium, classic methods of chemical analysis. The second part includes Sections 10-18 and covers instrumental methods of chemical analysis. The material of this textbook may be useful to future professionals as an overview of topics to continue learning at a deeper level. This knowledge is enough for a specialist to be able to work in analytical laboratories and control the quality of various products. Nobody can do your learning for you. The most important way to master this course is to work tasks and gain experience in the laboratory. Problem-solving may illustrate how to apply what you have just read. Exercises are the minimum set of problems that apply the most significant concepts of each chapter. Tables of dissociation constants and pK values for acids and bases, solubility-product constants for compounds, standard reduction potentials, formation constants (or stability constants) for complex ions in aqueous solutions, and densities of acids, alkalis and some other substances are shown in the last chapter of the textbook. 4 Section 1: Common Analytical Problems Contents: The vocabulary of analytical chemistry Classifying analytical techniques Selecting an analytical method Performance characteristics Stages of analysis Some items of labware Glassware Glassware cleaning Glassware calibration Other chemical vessels, accessories and techniques Introduction Analytical chemistry is connected with many other chemical and related disciplines. Typical problems that chemists-analysts work on include i) qualitative analysis (what does it consist of?), ii) quantitative analysis (how much of this component is in the sample?), iii) analysis of characteristics (what are the chemical and physical properties of the sample?) and iv) fundamental analysis (how does this method work and how can it be improved?). Many problems of analytical chemistry begin with the need to identify the constituent samples. It is the field of qualitative analysis. Much of the early work on analytical chemistry involved the development of simple chemical tests to detect inorganic ions and organic functional groups. Classical

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