22 Bull. Hist. Chem. 8 (1990)
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Experiment 5: Molar Volume of a Gas (Mg + Hcl)
1 CHEM 30A EXPERIMENT 5: MOLAR VOLUME OF A GAS (MG + HCL) Learning Outcomes Upon completion of this lab, the student will be able to: 1) Demonstrate a single replacement reaction. 2) Calculate the molar volume of a gas at STP using experimental data. 3) Calculate the molar mass of a metal using experimental data. Introduction Metals that are above hydrogen in the activity series will displace hydrogen from an acid and produce hydrogen gas. Magnesium is an example of a metal that is more active than hydrogen in the activity series. The reaction between magnesium metal and aqueous hydrochloric acid is an example of a single replacement reaction (a type of redox reaction). The chemical equation for this reaction is shown below: Mg(s) + 2HCl(aq) è MgCl2(aq) + H2(g) Equation 1 When the reaction between the metal and the acid is conducted in a eudiometer, the volume of the hydrogen gas produced can be easily determined. In the experiment described below magnesium metal will be reacted with an excess of hydrochloric acid and the volume of hydrogen gas produced at the experimental conditions will be determined. According to Avogadro’s law, the volume of one mole of any gas at Standard Temperature and Pressure (STP = 273 K and 1 atm) is 22.4 L. Two important Gas Laws are required in order to convert the experimentally determined volume of hydrogen gas to that at STP. 1. Dalton’s law of partial pressures. 2. Combined gas law. Dalton’s Law of Partial Pressures According to Dalton’s law of partial pressures in a mixture of non-reacting gases, the total pressure exerted is equal to the sum of the partial pressures of the individual gases. -
Single Pass Cooling Systems
A Sustainable Alternative to Single Pass Cooling Systems Amorette Getty, PhD Co-Director, LabRATS What is Single Pass Cooling? ● Used for distillation/reflux condensers, ice maker condensers, autoclaves, cage washers… ● Use a continuous flow of water from faucet to sewer o 0.25-2 gallons per minute, o up to 1,000,000 gallons of water/year if left on continuously Single Pass Cooling: Support ● “U.S. Environmental Protection Agency has ranked the elimination of single-pass cooling systems #4 on its list of top ten water management techniques” -Steve Buratto, Chair of Chemistry and Biochemistry department NOT Just a Sustainability Issue! California Nanosystems Institute (CNSI) flood in a second-floor laboratory in July, 2014. Water ran at ~1-2 gallons per minute for 6-10 hours, overflowing into a ground floor electron microscopy lab CNSI Flood Losses ● $ 2.2 Million in custom built research equipment ● Research shutdown for 4 months ● over 200 hours of staff time ● Insurance no longer covering this type of incident again Campus Responses to the Incident • CNSI ban on single pass cooling systems • TGIF grant financial incentive for optional change of single replacement systems • Chemistry and Material Research Laboratory (MRL) • Additional Grants being sought • Conversation at Campus and UC-level to regulate and replace these types of systems. Seeking Allies… ● “The replacement of single-pass cooling systems with closed-loop and water free systems would save water and represent a major advance in the sustainability efforts of the campus.” -Steve Buratto, Chair of Chemistry and Biochemistry department Barriers to Replacement ● “...major obstacle to replacing the single-pass cooling systems with closed-loop and water- free systems is cost. -
Determination of Calcium Metal in Calcium Cored Wire
Asian Journal of Chemistry; Vol. 25, No. 17 (2013), 9439-9441 http://dx.doi.org/10.14233/ajchem.2013.15017 Determination of Calcium Metal in Calcium Cored Wire 1,* 1 2 1 1 HUI DONG QIU , MEI HAN , BO ZHAO , GANG XU and WEI XIONG 1Department of Chemistry and Chemical Technology, Chong Qing University of Science and Technology, Chongqing 401331, P.R. China 2Shang Hai Entry-Exit Inspection and Quarantine Bureau, P.R. China *Corresponding author: Tel: +86 23 65023763; E-mail: [email protected] (Received: 24 December 2012; Accepted: 1 October 2013) AJC-14200 The calcium analysis method in cored wire products is mainly measuring the total calcium content, including calcium oxide and calcium carbonate. According to the chemical composition of calcium cored wire and the chemical property of the active calcium in it, the gas volumetric method has been established for the determination of calcium content in calcium cored wire and a set of analysis device is also designed. Sampling in the air directly, intercepting the inner filling material of samples, reacting with water for 10 min, using standard comparison method and then the accurate calcium content can be available. The recovery rate of the experimental method was 93-100 %, the standard deviation is less than 0.4 %. The method is suitable for the determination the calcium in the calcium cored wire and containing active calcium fractions. Key Words: Calcium cored wire, Active calcium, Gas volumetric method. INTRODUCTION various state of the calcium. However, because the sample is heterogeneous and the amount of the sample for instrumental 1-4 The calcium cored wire is used to purify the molten analysis is small, thus such sampling can not estimate charac- steel, modify the form of inclusions, improve the casting and teristics of the whole ones accurately, so there are flaws to use mechanical properties of the steel and also reduce the cost of the instrumental analysis to determine the calcium metal in steel. -
XXIX. on the Magnetic Susceptibilities of Hydrogen and Some Other Gases
Philosophical Magazine Series 6 ISSN: 1941-5982 (Print) 1941-5990 (Online) Journal homepage: http://www.tandfonline.com/loi/tphm17 XXIX. On the magnetic susceptibilities of hydrogen and some other gases Také Soné To cite this article: Také Soné (1920) XXIX. On the magnetic susceptibilities of hydrogen and some other gases , Philosophical Magazine Series 6, 39:231, 305-350, DOI: 10.1080/14786440308636042 To link to this article: http://dx.doi.org/10.1080/14786440308636042 Published online: 08 Apr 2009. Submit your article to this journal Article views: 6 View related articles Citing articles: 16 View citing articles Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=6phm20 Download by: [RMIT University Library] Date: 20 June 2016, At: 12:34 E 3o5 XXIX. On the MAgnetic Susceptibilities of llydrogen uud some otl~er Gases. /33/TAK~; S0~; *. INDEX TO SECTIONS. 1. INTRODUCTION. ~O. METI~OD OF 5LEASUREMENT. o. APPARATUS :FOR }IEASU14EIMF~NT. (a) Magnetic bMance. (b) Compressor and measuring tube. 4. PIt0CEDUI{E :FOR BIEASUREMENTS. (a) Adjustment of the measuring tube. (b) Determination of the mass. (c) Method of filling the measuring tube with gas. (d) Electromagnet. (e} Method of experiments. 5. Ain. 6. OXYGEN. ~. CARBON DIOXIDE. 8. NITROGEN. 9. ItYDI~0G~N. (a) Preparation of pure hydrogen gas. (b) Fillin~ the measuring tube with the gas. (e) YCesults el'magnetic measurement. (d} Purity of the hydrogen gas. 10. CONCLUDING REMARKS. wi. INTRODUCTION. N the electron theory of magnetism, it is assumed that I the magnetism is duo to electrons revolving about the positive nucleus in the atom; and hence the electronic structure of the atom has a very important bearing on its magnetic properties. -
A Study of Form and Content for a Laboratory Manual to Be Used by Students in General Chemistry Laboratory
Brigham Young University BYU ScholarsArchive Theses and Dissertations 1946-01-01 A study of form and content for a laboratory manual to be used by students in general chemistry laboratory Berne P. Broadbent Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd BYU ScholarsArchive Citation Broadbent, Berne P., "A study of form and content for a laboratory manual to be used by students in general chemistry laboratory" (1946). Theses and Dissertations. 8176. https://scholarsarchive.byu.edu/etd/8176 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. ?_(j;, . , i. ~ ~ (12 ' -8?5: 11% -· • A STUDY OF FOFM CONTENTFOR A LABORATORY -\ .AND MANUALTO BE USED BY STUDENTSIN GENERALCEEi/IISTRY LABORATORY' A THESIS SUBMITTEDTO \ THE DEPAR'.I3\t1Ell."'T OF CHEMISTRY OF ··! BRIGHAMYOUNG UNIVERSITY,. IN PARTIALFULFII.lllENT OF THEREQ,UIREMENTS·FOR THE DEGREE OF MASTEROF SCIENCE ... .,; . •·' .. ...• • .• . • "f ... ·.. .. ,. ·: :. !./:.•:-.:.lo>•.-,:... ... ... ..........• • • • p ,.. .,• • • ...• • . ~. ••,,. ................. :... ~•••,,.c • ..............• • • • • • .. f" ·~•-~-·"••• • • • ... • .., : :·.•··•:'"'•••:'"',. ·.-··.::· 147141 BY BERNEP. BROADBENT . " 1946 .,_ - ii \ ., This Thesis by Berne P.- Broadbent is accepted in 1ts P:esent form by the Departm·ent of Chem�stry as satisfying the Thesis requirement.for the degree of .J Master of Science • ,• . - .} .. iii PREF.ACE The constantly broadening field assigned to general chemistry demands that material be carefully selected and that ever increasing attention be given to preparing this material and presenting it_ to the student.- The following study was made to develop a laboratory manual that would increase the effectiveness of laboratory work. -
CHAPTER 15 the Laboratory
CHAPTER 15 The Laboratory These skills are usually tested on the SAT Subject Test in Chemistry. You should be able to . • Name, identify, and explain proper laboratory rules and procedures. • Identify and explain the proper use of laboratory equipment. • Use laboratory data and observations to make proper interpretations and conclusions. This chapter will review and strengthen these skills. Be sure to do the Practice Exercises at the end of the chapter. Laboratory setups vary from school to school depending on whether the lab is equipped with macro- or microscale equipment. Microlabs use specialized equipment that allows lab work to be done on a much smaller scale. The basic principles are the same as when using full-sized equipment, but microscale equipment lowers the cost of materials, results in less waste, and poses less danger. The examples in this book are of macroscale experiments. Along with learning to use microscale equipment, most labs require a student to learn how to use technological tools to assist in experiments. The most common are: Gravimetric balance with direct readings to thousandths of a gram instead of a triple-beam balance pH meters that give pH readings directly instead of using indicators Spectrophotometer, which measures the percentage of light transmitted at specific frequencies so that the molarity of a sample can be determined without doing a titration Computer-assisted labs that use probes to take readings, e.g., temperature and pressure, so that programs available for computers can print out a graph of the relationship of readings taken over time LABORATORY SAFETY RULES The Ten Commandments of Lab Safety The following is a summary of rules you should be well aware of in your own chemistry lab. -
Inquiry-Based Laboratory Work in Chemistry
INQUIRY-BASED LABORATORY WORK IN CHEMISTRY TEACHER’S GUIDE Derek Cheung Department of Curriculum and Instruction The Chinese University of Hong Kong Inquiry-based Laboratory Work in Chemistry: Teacher’s Guide / Derek Cheung Copyright © 2006 by Quality Education Fund, Hong Kong All rights reserved. Published by the Department of Curriculum and Instruction, The Chinese University of Hong Kong. No part of this book may be reproduced in any manner whatsoever without written permission, except in the case of use as instructional material in a school by a teacher. Note: The material in this teacher’s guide is for information only. No matter which inquiry-based lab activity teachers choose to try out, they should always conduct risks assessment in advance and highlight safety awareness before the lab begins. While every effort has been made in the preparation of this teacher’s guide to assure its accuracy, the Chinese University of Hong Kong and Quality Education Fund assume no liability resulting from errors or omissions in this teacher’s guide. In no event will the Chinese University of Hong Kong or Quality Education Fund be liable to users for any incidental, consequential or indirect damages resulting from the use of the information contained in the teacher’s guide. ISBN 962-85523-0-9 Printed and bound by Potential Technology and Internet Ltd. Contents Preface iv Teachers’ Concerns about Inquiry-based Laboratory Work 1 Secondary 4 – 5 Guided Inquiries 1. How much sodium bicarbonate is in one effervescent tablet? 4 2. What is the rate of a lightstick reaction? 18 3. Does toothpaste protect teeth? 29 4. -
HORIZONTAL BOTTLE COOLER EBC Series Model: EBC50
Project Name: HORIZONTAL BOTTLE COOLER Project Location: Model #: Quantity: Available Warehouse: EBC Series Model: EBC50 Refrigeration System ∙ Side mounted, self-contained and fully detachable Blizzard R290 condensing unit uses environmentally friendly, EPA-compliant R290 refrigerant with zero (0) Ozone Depletion Potential (ODP) and three (3) Global Warming Potential (GWP). Blizzard R290 is easily replaceable and requires no on-site brazing. ∙ Electronically commutated (ECM) fan motors achieve rapid cooling with less energy consumption. ∙ Full-length air duct system ensures optimal circulation of cold air. ∙ Time-initiated and temperature-terminated auto defrost cycle for seamless operation. ∙ Large capacity, corrosion-resistant condenser and evaporator coils. ∙ Self-maintaining, energy-efficient condensate drain pan requires no external drains or electric heaters. ∙ High performance, auto-reverse condenser fan motor supports compressor ventilation and condenser coil cleaning. Refer to owner’s manual for full maintenance instructions. ∙ Pre-wired and ready to plug, 115V/60Hz/1Ph, NEMA 5-15P. Cabinet Construction ∙ Heavy duty stainless steel countertop and rails with textured laminate, black vinyl exterior. ∙ Open spaced interior with no walls between compartments. ∙ Galvanized steel interior. ∙ 1 3/4" thick high density polyurethane insulation. ∙ Built-in caster thread receptacles for all models. Lighting ∙ Shielded LED bar lighting with on/off switch provides bright, high color illumination at lower heat output. Bottle Cap Opener ∙ Front mounted bottle cap opener and cap catcher are removable for ease of cleaning. Lids ∙ Heavy duty stainless steel exterior and galvanized steel interior. ∙ 3/4" thick high density polyurethane insulation. ∙ Removable ratchet locks keep your items safe from theft. Shelving ∙ Horizontal epoxy coated, steel wire shelves for bottom air circulation (see table for quantity). -
LSC- DTS Laboratory Sample Condenser
Quality System Certified ISO 9001 LSC-DTS Sample Condenser Rev.2.doc Page 1 of 1 LSC- DTS Laboratory Sample Condenser LSC- DTS Laboratory Sample Condenser This LSC unit range of stainless steel tube shaft sterile heat exchangers with Double Tube Sheet (DTS) have been designed to allow Clean Steam (CS) and Water For Injection (WFI) samples to be taken quickly and easly whilst mantaining a sterile testing environment. LSC are ideal to be mounted at the sampling point and can be operated with either mains or chilled water as the cooling medium. Availability of aseptic sample valve allow fine control of sample flow during testing The LSC can be sterilised in situ-on-line, thus ensuring continuity of samples regardless of testing frequency, ideal for fluids in pharmaceutical and purity systems applications. Typical applications: Steam sampling In-line conductivity monitoring Point of use cooling Feature offered by the unit include: AISI 316L (1.4404) stainless steel construction Double Tube Sheet (DTS) Meets FDA and 3A specifications Full material traceability Self draining design Compact, easy to install Fully sterilisable/autoclavable Sample Condenser operation The medium to be condensed/cooled passes throught the tube side. Typically a regulating valve will be used to throttle the sample medium flow. Cooling water is channelled countercurrent inside the shell in order to ensure maximum efficiency. The heat energy of the sample medium is absorbed by the flowing cooling water, resulting in a drop in the sample temperature. Where steam is the sample medium, the cooling water will firstly absorb the steam’s latent heat content, condensing it back to water. -
Grignard Synthesis of Triphenylmethanol Reactions That Form Carbon-Carbon Bonds Are Among the Most Useful to the Synthetic Organic Chemist
1 Experiment 12: Grignard Synthesis of Triphenylmethanol Reactions that form carbon-carbon bonds are among the most useful to the synthetic organic chemist. In 1912, Victor Grignard received the Nobel prize in chemistry for his discovery of a new series of reactions that result in the formation of a carbon-carbon bond. A Grignard synthesis first involves the preparation of an organomagnesium reagent via the reaction of an alkyl bromide with magnesium metal: δ– δ+ R Br + Mg R MgBr The resulting “Grignard reagent” acts as both a good nucleophile and a strong base. Its nucleophilic character allows it to react with the electrophilic carbon in a carbonyl group, thus forming the carbon-carbon bond. Its basic property means that it will react with acidic compounds, such as carboxylic acids, phenols, thiols and even alcohols and water; therefore, reaction conditions must be free from acids and strictly anhydrous. Grignard reagents will also react with oxygen to form hydroperoxides, thus they are highly unstable when exposed to the atmosphere and are generally not isolated from solution. For a variety of reasons, anhydrous diethyl ether is the solvent of choice for carrying out a Grignard synthesis. Vapors from the highly volatile solvent help to prevent oxygen from reaching the reaction solution. In addition, evidence suggests that the ether molecules actually coordinate with and help stabilize the Grignard reagent: Et Et O R Mg Br O Et Et The magnesium metal used in the synthesis contains a layer of oxide on the surface that prevents it from reacting with the alkyl bromide. The pieces of metal must be gently scratched while in the ether solution to expose fresh surface area so that the reaction can commence. -
CHEM 344 Distillation of Liquid Mixtures
CHEM 344 Distillation of liquid mixtures 1. Distillation basics The vaporization of a liquid and condensation of the resulting vapor is the basis of distillation. Organic liquids containing small amounts (<15%) of impurities or non-volatile substances are easily purified by simple distillation, as are liquid mixtures where the difference in boiling point of the components is >70 oC. Fractional distillation is more useful for separating mixtures of liquids where the boiling points of the components differ by <70 oC (see later). A typical simple distillation setup is shown in Figure 1. It consists of a flask containing the liquid to be distilled, an adapter to hold a thermometer and to connect the flask to a water-cooled condenser, and a flask to hold the condensed liquid (the distillate). Figure 1: Apparatus for a simple distillation. 1.1 The distillation flask The distillation flask is a round-bottom flask. The liquid to be distilled should fill the distillation flask to ~50-60% of its capacity. To promote even heating of the liquid, a boiling chip or a magnetic stir bar is added before heat is applied to the distillation flask. The irregular chips provide sites for bubbles of vapor to form, or alternatively the liquid is agitated with the magnetic stirrer as it is being heated. Never add a boiling chip or a stir bar to a hot liquid! Doing so can cause a seemingly calm liquid to boil suddenly and violently. 1 1.2 The distilling adapter The adapter connects the distillation flask, the condenser, and the thermometer. This type of adapter is often referred to as a distillation head. -
Laboratory Equipment Used in Filtration
KNOW YOUR LAB EQUIPMENTS Test tube A test tube, also known as a sample tube, is a common piece of laboratory glassware consisting of a finger-like length of glass or clear plastic tubing, open at the top and closed at the bottom. Beakers Beakers are used as containers. They are available in a variety of sizes. Although they often possess volume markings, these are only rough estimates of the liquid volume. The markings are not necessarily accurate. Erlenmeyer flask Erlenmeyer flasks are often used as reaction vessels, particularly in titrations. As with beakers, the volume markings should not be considered accurate. Volumetric flask Volumetric flasks are used to measure and store solutions with a high degree of accuracy. These flasks generally possess a marking near the top that indicates the level at which the volume of the liquid is equal to the volume written on the outside of the flask. These devices are often used when solutions containing dissolved solids of known concentration are needed. Graduated cylinder Graduated cylinders are used to transfer liquids with a moderate degree of accuracy. Pipette Pipettes are used for transferring liquids with a fixed volume and quantity of liquid must be known to a high degree of accuracy. Graduated pipette These Pipettes are calibrated in the factory to release the desired quantity of liquid. Disposable pipette Disposable transfer. These Pipettes are made of plastic and are useful for transferring liquids dropwise. Burette Burettes are devices used typically in analytical, quantitative chemistry applications for measuring liquid solution. Differing from a pipette since the sample quantity delivered is changeable, graduated Burettes are used heavily in titration experiments.