Department of Education and Science of Ukraine National University of Food Technologies
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DEPARTMENT OF EDUCATION AND SCIENCE OF UKRAINE NATIONAL UNIVERSITY OF FOOD TECHNOLOGIES APPROVED _______________A.I. Ukrainets (signature) «_____» ___________2016 y. V.N. ISCHENKO М.S. SОVКО N.V. ISCHENKO EQUIPMENT AND SAFETY IN CHEMICAL LABORATORY All quotations, digital and actual material, bibliographical information are checked. Writing units respond to the standards Signature (s) of the author (s) _____________________ « _17 » __May__2016 y. Registration number of electronic textbook in EMM 59. 04 – 07. 06. 2016 KIEV NUFT 2016 UDC 542.07 Recommended by the Academic Council of the National University of Food Technologies as learner’s guide for students of higher educational establishments (Minutes № 13 from 31.05. 2016) Reviewers: V.I Maksin – Dr. of Chemistry, Professor of the Department of Bioinorganic Chemistry and Water Quality NUBaN Ukraine O.O. Tkachuck – Ph.D. in Chemistry, the head of the laboratory ofnational anti-doping center of Ukraine O.V. Berezovska – senior lecturer of the Department of Business Foreign Language and International Communication NUFT IschenkoV.N. Equipment and safety in chemical laboratory [Electronic resourse]:learner’s guide /V.N. Ischenko, М.S. Sоvко, N.V. Ischenko. – K.: NUFT, 2016. –27 р. The learner’s guide provides information about modern chemical laboratory equipment. Chemical laboratory ware and equipment necessary for conducting laboratory work are described. The guide provides the rules of behavior and safety in chemical laboratory, rules of work with chemicals Learner’s guide is recommended for students of academic level of bachelor, who study Chemistry in English. Authors: V.N. ISCHENKO, PhD М.S. SОVКО, N.V. ISCHENKO, PhD Introduced in author’s edition © V.N. Ischenko, 2016 © М.S. Sоvко, 2016 © N.V. Ischenko,2016 © NUFT, 2016 2 Introduction Chemistry is a major subject for the university students of technological universities. Conducting laboratory works which let experimentally proves theoretical rules and regularities of chemical processes is very important. In order to conduct laboratory work and experiments correctly, it is necessary not only to understand the task, but to know the technology of laboratory works. According to D. Mendeleev, the technology of laboratory work is subject mastery. It includes safety rules, ability to deal with laboratory equipment, ability to conduct chemical experiments correctly and rules of behavior in chemical laboratory. The learner’s guide provides information about modern chemical laboratory equipment. Chemical laboratory ware and equipment are described: glassware for general and special purposes, volumetric and pottery equipment, other tools, instruments and equipment necessary for conducting laboratory work. The guide provides the rules of behavior and safety in chemical laboratory, rules of work with chemicals and guidance to record a laboratory notebook. Information in Appendix is also useful: the scheme of simple distillation with the names of all its parts and the table with possible tolerance for volumetric glassware. Learner’s guide is aimed at students of academic level of bachelor, whostudyСhemistry in English, to prepare for laboratory and practical works. 3 1. Laboratory glassware and other equipment 1.1. Tubes 1 Test tubes are widely used by chemists to hold, mix, or heat small quantities of solid or liquid chemicals, especially for qualitative experiments and assays. Their round bottom and straight sides Test tube minimize mass loss when pouring, make them easier to clean, and allow convenient monitoring of the contents. The long, narrow neck slows down the spreading of vapours and gases to the environment. 2 Centrifuge tubes are precision-made, high-strength tubes of glass or plastic made to fit exactly in rotor cavities. Centrifuge They may vary in capacity tube from 50 mL down to much smaller capacities used in microcentrifuges used extensively in molecular biology laboratories. 1.2. Filtering equipment 3 The Buchner is used exclusively for vacuum filtrations. The adaptor forms Buchner a snug seal so that when funnel reduced pressure is applied to the vacuum flask, liquid poured into the Buchner is sucked into the flask quickly. 4 4 A Buchner flask can be used with a Buchner funnel for separating solids and liquids. Water is poured into the Buchner Buchner funnel and the liquid flask passes through filter paper (vacuum and is sucked up by a vacuum flask) attached to the side of the Buchner flask, while the solid stays behind in the Buchner funnel. 5 Stemmed funnels are used for gravity filtration. They are Long-stem also used for miscellaneous funnel tasks such as filling round bottom flasks with liquids. 6 Powder funnels have a small Powder and wide neck for fast pouring funnel of powders. 7 Filter papers are widely used in laboratory experiments across many different fields. In most condition, filter Filter paper papers work with other laboratory technique such as gravity filtration, vacuum filtration. 5 1.3. Laboratory funnels 8 A separatory funnel, is a piece of laboratory glassware used in liquid-liquid extractions to Separatory separate (partition) the funnel components of a mixture into two immiscible solvent phases of different densities 9 Dropping funnels are useful for adding reagents slowly, i.e. drop-wise. This may be Droppingfun desirable when the quick nel addition of the reagent may result in side reactions, or if the reaction is too vigorous. 1.4. Distilling equipment 10 The Claisen adaptor is a multi-purpose item of standard taper glassware. It is used in situations which require more than one outlet from a round-bottom flask. For instance, in a reflux of a Claisen reaction mixture, sometimes it adapter is necessary to condense the rising vapors and add reactants to the mixture at the same time. In this situation, one of the upper joints of the Claisen adaptor would go to a condenser and one to a dropping or separatory funnel. 6 11 The three-way adapter is used in a distillation set-up. The lower joint attaches to the distillation flask or Three-way fractionating column, the adapter upper joint attaches to the thermometer adapter, and the side joint connects to the condenser. 12 The vacuum adaptor (shown on the right) is used in a distillation set-up: it connects Vacuum to the lower end of the adapter condenser and serves to direct the distilled liquid into the receiving flask. 13 A laboratory fractionation column is a piece of glassware Fractionation used to separate vaporized column mixtures of liquid compounds with close volatility. 14 The condensersare used in both reflux and distillation procedures as to cool and condense vapors. In simplest Liebig form, a condenser can consist condenser of a single tube of glass or metal, where the flow of outside air produces the cooling. In a further simple 7 15 form, condensers consist of concentric glass tubes, with the tube through which the hot gases begin to pass running the length of the apparatus. The second tube defines an outer chamber through which air, water, or other cooling fluids can pass to reduce the temperature of the gasses to afford the condensation; hence, the outer tube (or, as designs become more Allihn complex, outer cooling condenser chamber) has an inlet and an outlet to allow the cooling fluid to enter and exit. The Allihn condenser consists of a long glass tube with a water jacket. A series of bulbs on the tube increases the surface area upon which the vapor constituents may condense. Ideally suited for laboratory-scale refluxing. Simple distillation setup is shown at Appendix I. 16 Round-bottom flasks are used in a variety of applications where the contents are heated or boiled. Round-bottom Round- flasks are usually used in bottom flask distillation as distilling flasks and receiving flasks for the distillate. This flask shape is also more resistant to 8 17 fracturing under vacuum, as a sphere more evenly distributes stress across its surface. Round-bottom flasks are often used to contain chemical reactions, especially for reflux set-ups and laboratory-scale synthesis. 18 Three-neck round- bottom flask 1.5. Volumetric equipment 19 Erlenmeyer flask Erlenmeyer flasks and beakers are used for mixing, transporting, and reacting, but not for accurate 20 measurements. The volumes stamped on the sides are approximate and accurate to within about 5%. Laboratory beaker 9 21 Volumetric flasks (are manufactured with capacities ranging from 5 mL to 5 L and are usually calibrated to contain (TC) a specified Volumetric volume when filled to a line flask etched on the neck. They are used for the preparation of standard solutions and for the dilution of samples to a fixed volume prior to taking aliquots with a pipet. 22 Pipettes permit the transfer of accurately known volumes Volumetric from one container to another. pipette A volumetric, or transfer, (single- pipette delivers a single, fixed volume volume between 0,5 and 200 pipette) mL. Many such pipettes are color coded by volume for convenience in identification 23 and sorting. Graduated measuring pipettes are calibrated in convenient units to permit delivery of any volume up to a maximum capacity ranging Graduated from 0,1 to 25 mL. measuring Because most liquids are pipette attracted to glass, a small amount of liquid tends to remain in the tip after the pipette is emptied. This residual liquid is never blown out of a volumetric pipette. 10 24 Eppendorf micropipettes deliver adjustable microliter volumes of liquid. With these pipets, a known and adjustable volume of air is displaced from the plastic Piston pipete disposable tip by depressing (Eppendorf the pushbutton on the top of micropipette the pipet to a first stop. s) The accuracy and precision of automatic pipets depend somewhat on the skill and experience of the operators and thus should be calibrated for critical work. 25 Burettes, like measuring pipettes, make it possible to deliver any volume up to the maximum capacity of the device.