DOCSLIB.ORG

«Elements of Quantitative Analysis. the Quantitativecomposition of the Solutions

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
«Elements of Quantitative Analysis. the Quantitativecomposition of the Solutions MINISTRY of PUBLIC HEALTH of UKRAINE ODESSA NATIONAL MEDICAL UNIVERSITY Department of Clinical Chemistry and Laboratory Diagnostics Medical chemistry Information block for first-year students of medical faculty Part 2. Acid-base equilibrium in biological fluids «Elements of quantitative analysis. The quantitativecomposition of the solutions. Methods for calculating the concentration of solutions Test questions: 1. Solutions and their composition. 2. Physical and chemical theory of solutions 3. Ways to express the composition of the solution. 3. Solubility. Factors affecting solubility. 4. Concentration. Types of concentration. Ways to express concentrations. 5. The role of solutions in nature, living organisms, science and technology. The biological role of solutions. 1 6. Hydrates, crystalline hydrates, crystallization water. 7. Medical solutions. Doses Calculation of the dosage of the drug. Theoretical basis 1.1. Composition of solutions. Solutions are of great practical importance. Many chemical and biochemical reactions proceed in solutions. Solutions are homogeneous systems of variable composition, consisting of two or more substances (components). A true solution is a homogeneous system formed by at least two components. The composition of the solution can be changed continuously within certain limits. The true solution differs from colloidal solutions and mechanical mixtures (suspensions, emulsions, aerosols). Colloidal solutions are multicomponent heterogeneous systems. The homogeneity of the solutions makes them similar to chemical compounds and distinguishes them from mechanical mixtures. Solutions can be in three states of aggregation: gaseous, solid and liquid. In solid solutions, particles of one substance are randomly distributed among particles of another solid. For example, hydrogen is well soluble in some metals (platinum, palladium), and this is a solid solution. Mixtures of gases (e.g. air) are not called solutions. The fact is that an important property of solutions is a noticeable interaction between solvent particles and dissolved substances, and in gases such interaction is practically absent. In liquid solutions, the solvent and the solute are distinguished. A solvent is a substance that is in the same state of aggregation as the solution. If the aggregate state of the substances that make up the solution is the same (for example, alcohol and water), then the solvent is a substance that is present in excess compared to other components. The remaining components, which are in solution in a smaller amount, are called solutes. According to modern theory, solutions are liquid dissociated systems formed by particles of solvent and solute and those uncertain compounds that form between them. 2 Dissolution is a physicochemical process. When dissolving, heat is always released or absorbed, and a change in volume occurs. This indicates a chemical interaction between the solute and the solvent. As a result of this interaction, solvates or hydrates (solvent- water) are formed. On the other hand, solutions do not obey the law of constancy of composition; they, like mixtures, can be divided by physical methods into their constituent parts. Most hydrates and solvates are weak compounds that decompose readily. However, hydrates can also be strong; they can be easily isolated during crystallization. Examples of crystalline hydrates: CuSO4·5H2O, CaSO4·2H2O, BaCl2·2H2O. Such medicinal substances also include glucose, terpinghydrate, magnesium sulfate, copper sulfate, alum, codeine, etc., which are crystalline hydrates with different contents of crystallization water. When water is removed from crystalline hydrates, they change the appearance and individual properties (copper sulfate, gypsum, crystalline soda, etc.). In the hydrated state, individual ions of salt dissolved in water also remain, which is crucial for many properties of salt solutions. In chemical practice, the most important are liquid solutions. Qualitatively, by the ratio of the dissolved substance and the solvent, the solutions are divided into: concentrated – solutions in which there is a lot of dissolved substance; diluted – solutions in which there is little solute. But these concepts are conditional, relative and indefinite. The following classification of solutions is more defined.: saturated solution is a solution in which at a given temperature the substance no longer dissolves, i.e. in this case the solubility product (SP) is equal to the product of ion concentrations in degrees equal to stoichiometric coefficients; unsaturated solution is a solution in which at a given temperature there is less soluble substance than in a saturated solution, i.e. in this case the solubility product (SP) is less than the product of ion concentrations in degrees equal to stoichiometric coefficients ; 3 supersaturated solution is a solution in which at a given temperature in the dissolved state there is more substance than in its saturated solution under the same conditions, ie an in this case the solubility product (SP) is bigger than the product of ion concentrations in degrees equal to stoichiometric coefficients ; . Oversaturated solutions are very unstable. They are able to exist only in the absence of a solid phase of a dissolved substance. Crystallization can be caused by the addition of crystalline, shaking, friction with a stick on the walls of the vessel. 1.2. Solubility Solubility is the ability of a substance to dissolve in a particular solvent. Solubility is a spontaneous physicochemical process. It occurs due to the diffusion of molecules or ions from a region with a higher concentration to a region with a lower concentration. As a result, the substance is evenly distributed throughout the solution. Solubility is a bidirectional process: a solid goes into solution, and a dissolved substance goes into a solid. Therefore, both dissolution and crystallization occur simultaneously. These processes proceed with the same speeds over time - dynamic equilibrium sets in. In this case, the concentration of the soluble substance remains constant without changing the conditions. This condition is called the saturation state, and the solution is called saturated. The ability of various substances to dissolve in a particular solvent is called solubility. A measure of solubility is the princiconcentration of a saturated solution at a given temperature and pressure. The dynamic equilibrium Le Chatelier`s principle is applicable to the dissolution process. Solubility depends on temperature, external pressure, nature of the solute and solvent. If more than 10 g of a substance is dissolved in 100 g of water, then such a substance is called highly soluble. If less than 1 g of the substance is dissolved, the substance is sparingly soluble. A substance is considered practically insoluble if less than 0.01 g of the substance passes in solution. Absolutely insoluble substances do not exist. Even when we pour water into a glass vessel, a very small part of the glass molecules inevitably passes into solution. 4 Depending on the content of the solute and the ratio of the rates of dissolution and crystallization processes, saturated, unsaturated and supersaturated solutions are distinguished. In general form for any sparindly soluble electrolyte: y+ x- (AxBy )cryst = xA + yB . If T= const, [AxBy]=const, we get the following expression: y+ x x- y Keq*[AxBy]= [A ] *[B ] = SPAxBy In a saturated salt solution, the product of the concentrations of its ions (activities) in powers equal to stoichiometric coefficients is a constant value at a given temperature, called the product of solubility (SP). If the stoichiometric product of ion concentrations is greater than SP, then the solution is supersaturated and a precipitate forms. If the stoichiometric product of ion concentrations is less than SP, then the solution is unsaturated and a precipitate will dissolve. If the stoichiometric product of ion concentrations, SP are equal, then the solution is saturated. Solubility expressed by the mass of a substance that can dissolve in 100 g of water at a given temperature is also called the solubility coefficient. The mutual solubility of liquids or solids in liquids depends on a number of properties of these substances: chemical nature, value and structure of particles, electric charge (in the case of ions), dipole moment and others. Unlimited solubility is when two liquids dissolve one into the other in any ratio. Limited solubility is one liquid that dissolves in another in a certain concentration. With limited mutual solubility of the two liquids A and B, each of them dissolves. However, after settling, two layers are formed, which are arranged one above the other in the order of decreasing density. Information on the solubility of drugs is given in pharmacopeia articles and reference tables. 5 1.3 Сoncentration of solution The main characteristic of the solution is its concentration. In chemistry, the concentration of a solution is the quantity of a solute that is contained in a particular quantity of solvent or solution. Knowing the concentration of solutes is important in controlling the stoichiometry of reactants for solution reactions. Chemists use many different methods to define concentrations, some of which are described in this section. Quantitatively, the concentration of the solution is expressed in many ways. Six methods for expressing the concentration of solutions are most commonly used.: mass fraction.............................................................................
Load more

Recommended publications
  • Absolute Measurement of the Abundance of Atmospheric Carbon Monoxide C
    Absolute measurement of the abundance of atmospheric carbon monoxide C. Brenninkmeijer, C. Koeppel, T. Röckmann, D. Scharffe, Maya Bräunlich, Valerie Gros To cite this version: C. Brenninkmeijer, C. Koeppel, T. Röckmann, D. Scharffe, Maya Bräunlich, et al.. Absolute mea- surement of the abundance of atmospheric carbon monoxide. Journal of Geophysical Research: At- mospheres, American Geophysical Union, 2001, 106 (D9), pp.10003-10010. 10.1029/2000JD900342. hal-03117189 HAL Id: hal-03117189 https://hal.archives-ouvertes.fr/hal-03117189 Submitted on 8 Feb 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 106, NO. D9, PAGES 10,003-10,010, MAY 16, 2001 Absolute measurement of the abundance of atmospheric carbon monoxide C. A.M. Brenninkmeijer,C. Koeppel,T. R6ckmann,D. S. Scharffe, Maya Br•iunlich,and Valerie Gros AtmosphericChemistry Division, Max PlanckInstitute for Chemistry,Mainz, Germany Abstract.The main aspects of anabsolute method for measurementof the mixing ratio of atmos- phericcarbon monoxide (CO) are presented. The method is based on cryogenic extraction of CO fromair afteroxidation to CO2followed by accuratevolumetric determination. Gravimetric meas- urementis usedto determinethe quantity of sampleair processed.In routineoperation the overall errorcan be kept below 1%.
    [Show full text]
  • Effects on Accuracy and Detection Limits
    WHITE Sensitivity, Background, Noise, and Calibration in Atomic PAPER Spectroscopy: Effects on Accuracy and Detection Limits Introduction Proper calibration in atomic spectroscopy and an understanding The three most common atomic spectroscopy techniques of uncertainty is fundamental to achieving accurate results. This are atomic absorption (AA) spectroscopy, ICP optical emission paper provides a practical discussion of the effects of noise, error spectroscopy (ICP-OES) and ICP mass spectrometry (ICP-MS). and concentration range of calibration curves on the ability to Of these, ICP-OES and ICP-MS are very linear; that is, a plot determine the concentration of a given element with reasonable of concentration vs. intensity forms a straight line over a accuracy. The determination of lower limits of quantitation and wide range of concentrations (Figure 1). AA is linear over a lower limits of detection will also be discussed. much smaller range and begins to curve downward at higher Results accuracy is highly dependent on blank contamination, concentrations (Figure 2). Linear ranges are well understood, linearity of calibration standards, curve-fitting choices and the and, for AA, a rule of thumb can be applied to estimate the range of concentrations chosen for calibration. Additional factors maximum working range using a non-linear algorithm. include the use of internal standards (and proper selection of This paper will discuss the contributions of sensitivity, internal standards) and instrumental settings. background, noise, calibration range, calibration mathematics This paper is not intended to be a rigorous treatment of statistics and contamination on the ability to achieve best accuracy and in calibration; many references are available for this, such as lowest detection limits.
    [Show full text]
  • Combined Wastestream Formula (CWF)
    UnitedStates PermitsDivision and September1985 EnvironmentalProtection IndustrialTechnology Division Agency Washington,DC 20460 Water EPA Guidance Manual Pretreatment for the Use of Production-Based Pretreatment Standards and the Combined Wastestream Formula UNITED STATES ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. 20460 SEP 19 1985 OFFICEOF WATER MEMORANDUM SUBJECT: Pretreatment Program Guidance FROM: Rebecca W. Hanmer, Director Office of Water Enforcement and Permits (EN-335) James M. Conlon, Acting Director Office of Water Regulations and Standards (WH-551) TO: Users of the Guidance Manual for the Use of Production- Based Categorical Pretreatment Standards and the Combined Wastestream Formula This guidance manual has been developed by EPA to explain how to implement two important elements of the national pretreatment program: categorical standards and the combined wastestream formula. The manual is divided into two sections. The first section explains how to apply production-based categorical standards in a permit, contract, or similar mechanism. The second part explains how to use the combined wastestream formula, providing definitions and examples. The manual is one of a series of guidance documents intended to simplify and improve understanding of various aspects of the pretreatment program. Other documents in this series which have either been recently issued or will be issued in the near future will provide guidance on: 1) Removal Credits 2) Total Toxic Organics (TTO) Monitoring 3) RCRA Notification Requirements 4) Local Limits 5) POTW Interference The need for guidance on the use of categorical standards and the combined wastestream formula was recognized by the Pretreatment Implementation Review Task Force (PIRT). PIRT was set up by the EPA Administrator to make recommendations concerning the problems faced by POTWs, states, and industry in implementing the national pretreatment program.
    [Show full text]
  • 3.1 Polarization Behavior of Active Passive Metals and Alloys Glossary
    3.1 Polarization Behavior of Active Passive Metals and Alloys John R. Scully, Katie Lutton Center for Electrochemical Science and Engineering Department of Materials Science and Engineering University of Virginia, Charlottesville, VA, United States Glossary Symbol Explanation 퐸푃 Primary passivation potential 퐸푃2 Primary activation potential 푖푐푟푖푡 Critical current density 퐸푡푟푎푛푠 Transpassive potential 퐸푃1 First primary passivation potential 표 퐸푃 Hypothetical standard primary passivation potential based on a half-cell reaction 휏푃 Critical time for passivation 푆퐻퐸 Standard hydrogen electrode 푖푝푎푠푠 Passive current density 푖lim ⁡ Limiting current density for a mass transport limited cathodic reaction Abstract The objective of this chapter is to summarize the relationships between electrochemical potential and current density for typical transition metals such as Fe, Cr, and Ni. Key parameters such as the active passive transition, primary and secondary passivation potentials, critical anodic current density, passive current density, and transpassive region are presented, defined, and interpreted to explain typical E-log(i) diagrams and polarization curves. Consideration is given to the polarization behavior of a passivating electrode resulting from both the anodic and cathodic partial currents using mixed potential theory. The impact of the reversible electrode potential and polarizability of an oxidizing reducible species on the observed E-log(i) polarization behavior of such passivated materials is discussed. The kinetics of the passive film
    [Show full text]
  • Florpyrauxifen-Benzyl & Degradates in Compost
    Page 16 INTRODUCTION Scope The objective of the study was to independently validate analytical method as given in the DAS study 171407 [1] for the determination of Florpyrauxifen benzyl (XDE-848 BE), X11438848 and X11966341 in compost in accordance to the guidance documents SANCO/825/00, rev. 8.1 [2] and SANCO/3029/99 rev. 4 of the European Commission [3], and OCSPP 850.6100 of the United States Environmental Protection Agency [4]. The limit of quantification was 0.00015 mg/kg for Florpyrauxifen benzyl (XDE-848 BE), 0.00045 mg/kg for X11438848 and 0.009 mg/kg for X11966341 Analytical Procedure Compost samples were extracted by shaking with acetonitrile/0.1N hydrochloric acid (90:10, v/v), centrifuging, and decanting into a separate tube containing QuEChERS Citrat kit. An aliquot of 1N HCl was added to the extract followed by centrifugation. After a portion of the organic layer was aliquoted, internal standard was added and the sample was evaporated to near dryness under a stream of nitrogen. 1N HCl was added and the samples were incubated for one hour at 80 °C. Ethyl acetate was added and the samples were transferred to a Supel QuE Z-Sep tube and centrifuged. After centrifuging, the samples were placed in a dry ice bath to flash freeze the aqueous layer and the organic layer was poured off into a glass tube. The samples were evaporated under a stream of nitrogen, reconstituted in methanol and 0.1% formic acid in water, and transferred into an autosampler vial for analysis. The samples were analyzed for XDE-848 BE and its metabolites by liquid chromatography with positive ion electrospray ionization tandem mass spectrometry Selectivity Quantification was performed by use of LC-MS/MS detection.
    [Show full text]
  • Solution Density Modelling for Single and Mixed Base Metal Electrolytes at Ionic Level
    CORE Metadata, citation and similar papers at core.ac.uk Provided by Wits Institutional Repository on DSPACE SOLUTION DENSITY MODELLING FOR SINGLE AND MIXED BASE METAL ELECTROLYTES AT IONIC LEVEL Trevor Chagonda A research report submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, in partial fulfilment of the requirements for the degree of Master of Science in Metallurgical Engineering Johannesburg 2013 DECLARATION I declare that this research report is my own unaided work. It is being submitted in partial fulfilment of the requirements of the degree of Master of Science in Metallurgical Engineering at the University of Witwatersrand, Johannesburg. It has not been submitted before for any degree or examination to any other university. ……………………………………. (Signature of Candidate) …………….. DAY OF ……………………………. YEAR …………………… ABSTRACT Solution density modeling is important in hydrometallurgical processes as accurate predictions of single and mixed electrolytes can be used in the design of equipment and their sizing, heat transfer calculations and choosing of materials for construction. This research project entails modeling of electrolyte solutions by extending the Laliberte and Cooper (compound level) model to ionic level where an electrolyte solution is modeled as a mixture of cations, anions and water molecules. This modeling predicts single and mixed electrolyte density as a function of electrolyte temperature in degrees Celsius; water, cation and anion apparent volumes in cubic centimeters; and their respective concentrations in the electrolyte as mass fractions. The model was developed by fitting single electrolyte density data reported in literature using the least squares method in Microsoft Excel®. The following 26 single electrolyte solutions were used in the fitting exercise: Al2(SO4)3, BaCl2, CaCl2, CdSO4, CoCl2, CuSO4, FeCl3, FeSO4, HCl, HCN, HNO3, K2CO3, LiCl, MgSO4, MnCl2, Na2SO3, NaF, NaI, NaOH, (NH4)2SO4, NiCl2, SrCl2, ZnCl2, ZnBr2, (NH4)2C2O4 and KNO2.
    [Show full text]
  • Human Health Criteria Options February 2017
    Water Quality Policy 1-11 Updates Human Health Criteria February 2017 Outline of Issues covered: I. Background II. Factors to consider for the use of tissue samples Tissue sample representativeness Species to represent segment/site fidelity III. Factors to consider for the use of water samples IV. Lines of Evidence Tissue exposure concentration Drinking water exposure concentration Water column data DOH fish advisories Safe Drinking Water Act (SDWA) MCL values V. Weight of evidence VI. Category determinations I. Background The surface water quality standards include a section on toxic substances (WAC 173-201A-240) for the protection of designated uses. Numeric criteria have been developed for the designated uses of aquatic life and the protection of human health. Uses associated with human health are fish and shellfish harvesting (consumption of fish) and domestic water supply (drinking water). Human health-based water quality criteria used by the state prior to December 2016 were contained in the National Toxics Rule. Currently approved human health criteria (HHC) for Washington are a combination of state-adopted criteria and EPA promulgated criteria. In previous Water Quality Assessments, toxics data from fish tissue was used to assess for the protection of human health, deriving a Fish Tissue Equivalent Concentration (FTEC) as a means to back-calculate fish tissue pollutant concentrations to approximate surface water pollutant concentrations. This was done by applying bioconcentration factors (BCF) that were used to derive the HHC in the National Toxics Rule. The intent of the FTEC used for the past several years was to represent a water column criteria equivalent. On December 14, 2016, Ecology held a public dialogue session on human health criteria.
    [Show full text]
  • Calculation of the Electrophoretic Mobility of a Spherical Colloid Particle
    JOUI~NziL OF COLLOID £ND INTERFACE SCIENCE 9.2, 78--99 (1966) Calculation of the Electrophoretic Mobility of a Spherical Colloid Particle P. H. WIERSEMA, A. L. LOEB, AXD J. TH. G. OVERBEEK Van't Hoff Laboratory, University of Utrecht, The Netherlands. Ledgemont Laboratory, Kennecott Copper Corporation, Lexington, Massachusetts Received May 3, 1965 ABSTRACT A new calculation of the relation between the electrophoretic mobility and the/-- potential of a spherical colloid particle is presented. The model consists of a rigid, electrically insulating sphere surrounded by a Gouy-Chapman double layer. The ap- propriate differential equations (which account for both electrophoretic retardation and relaxation effect) have been solved without approximations on an IBM 704 com- puter. The theoretical assumptions and the basic equations ~re stated. A detailed account of the solutions of the equations is pub]ished elsewhere. The present paper contains the complete results. Comparison of these results with those of Overbeek ~nd of Booth shows that, %r high ~--potential ~nd 0.2 < ~a < 50, their approximations gen- erally overestimate the relaxation effect. The application to practical cases (espe- cially colloid particles in solutions of 1-1 electrolytes) is discussed extensively. Finally, the theoretical results are compared with experimental data published by others. INTRODUCTION particle, it is valid only when ~a }> 1, The calculation of the ~-potential from where a is the radius of the particle and measurements of the electrophoretic mobil- is the reciprocal thickness of the surround- ity (E.M.) requires a theoretical relation ing ionic atmosphere. For moderate values between the two quantities. The oldest of ~a (say, 0.2 < ~a < 50), the so-called relation of this kind, which was derived by relaxation effect leads to important correc- yon Helmholtz (1) and improved by yon tions, which increase with increasing /'- Smoluchowski (2), reads potential.
    [Show full text]
  • Test Chemical Solubility Protocol
    Test Method Protocol for Solubility Determination Phase III - Validation Study September 24, 2003 TEST METHOD PROTOCOL for Solubility Determination In Vitro Cytotoxicity Validation Study Phase III September 24, 2003 Prepared by The National Toxicology Program (NTP) Interagency Center for the Evaluation of Alternative Toxicological Methods (NICEATM) Based on Standard Operating Procedure Recommendations from an International Workshop Organized by the Interagency Coordinating Committee on the Validation of Alternative Methods (ICCVAM) National Institute of Environmental Health Sciences (NIEHS) National Institutes of Health (NIH) U.S. Public Health Service Department of Health and Human Services 1 Test Method Protocol for Solubility Determination Phase III - Validation Study September 24, 2003 TEST METHOD PROTOCOL Solubility Determination Phase III I. PURPOSE The purpose of this study is to evaluate the cytotoxicity of test chemicals using the BALB/c 3T3 Neutral Red Uptake (NRU) and normal human keratinocyte (NHK) cytotoxicity tests. The data will be used to evaluate the intra- and inter-laboratory reproducibility of the assay and effectiveness of the cytotoxicity assay to predict the starting doses for rodent acute oral systemic toxicity assays. This test method protocol outlines the procedures for performing solubility determinations for the in vitro validation study organized by NICEATM and the European Centre for the Validation of Alternative Methods (ECVAM) and sponsored by NIEHS, U.S. Environmental Protection Agency, and ECVAM. This test method protocol applies to all personnel involved with performing the solubility testing. A. Solubility Test The solubility tests will be performed to determine the best solvent to use for each of the 60 blinded/coded test chemicals to be tested in the 3T3 and NHK NRU cytotoxicity tests II.
    [Show full text]
  • Calculating Water Quality-Based Effluent Limitations for Surface Water Discharges
    BUREAU OF WATER QUALITY PROGRAM GUIDANCE Wastewater Policy and Management Team Wisconsin Department of Natural Resources 101 S. Webster Street, P.O. Box 7921 Madison, WI 53707-7921 Calculating Water Quality-Based Effluent Limitations for Surface Water Discharges 08/10/2020 EGAD Number: 3400-2020-13 This document is intended solely as guidance and does not contain any mandatory requirements except where requirements found in statute or administrative rule are referenced. Any regulatory decisions made by the Department of Natural Resources in any matter addressed by this guidance will be made by applying the governing statutes and administrative rules to the relevant facts. _____________________________________________________________________________________ APPROVED: Adrian Stocks 12/07/2020 _______________________________ __________ Adrian Stocks, Director Date Bureau of Water Quality Summary Section 283.13(5), Wis. Stats., requires that effluent limitations be established in permits for point source discharges to surface water to ensure that applicable state water quality standards are met. These types of effluent limitations are protective of water quality and are referred to as water quality- based effluent limits (WQBEL). The WQBEL calculation process completed by the Wisconsin Department of Natural Resources (the department) involves a site-specific evaluation of the discharge receiving water and effluent characteristics and comparison to state water quality standards. This guidance is intended for use by department staff who are responsible for calculating WQBELs. The document covers how WQBELs are calculated, how staff determine if limits are needed in permits, and how those limits should be expressed in WPDES permits for point source discharges to Wisconsin surface waters. The following guidance documents also provide information on WQBEL calculation procedures and are used by WQBEL calculation staff.
    [Show full text]
  • Sociation Constant of the Buffer and the Concentration and Reaction of the Buffer Solution.*
    ON THE MEASUREMENT OF BUFFER VALUES AND ON THE RELATIONSHIP OF BUFFER VALUE TO THE DIS- SOCIATION CONSTANT OF THE BUFFER AND THE CONCENTRATION AND REACTION OF THE BUFFER SOLUTION.* BY DONALD D. VAN SLYKE. (From the Hospital of The Rockefeller Institute for Medical Research.) Downloaded from (Received for publication, April 15, 1922.) CONTENTS. The nature and mode of action of buffers ............................ 525 Unit for measurement of buffer values ............................... 528 The buffer value of water plus only strong acid or alkali ............. 531 www.jbc.org The buffer value of a solution containing a weak monovalent acid anditssalt .................................................... 535 Fundamental mass law equations ................................ 535 Differentiation of Henderson’s equation in order to calculate the buffer values of weak acids .............................. 537 by guest, on September 19, 2010 Second derivative of Henderson’s equation. Point of maxi- mum buffer value ........................................... 542 General equation indicating the dissociation of a weak acid at all reactions within the limits of validity of the mass law ... 547 Polyvalent acid buffers and mixtures of monovalent acid buffers ..... 553 Basicbuffers ........................................................ 557 Amphotericbuffers .................................................. 558 Universalbuffermixtures ............................................. 558 The buffer value of blood ...........................................
    [Show full text]
  • Corrosion and Deuterium Uptake of Zr-Based Alloys in Supercritical Water
    CW-124680-CONF-001 UNRESTRICTED - ILLIMITÉ Corrosion and Deuterium Uptake of Zr-based Alloys In Supercritical Water D. Khatamian AECL, Chalk River Laboratories, Stn. 55 Chalk River, ON K0J 1J0, Canada [email protected] Abstract To increase the thermodynamic efficiency above 40% in nuclear power plants, the use of supercritical water as the heat transport fluid has been suggested. Zircaloy-2, -4, Zr-Cr-Fe, Zr-1Nb and Zr-2.5Nb were tested as prospective fuel cladding materials in 30 MPa D2O at 500 C. Zircaloy-2 showed the highest rates of corrosion and hydriding. Although Zr-Cr-Fe initially showed a very low corrosion rate, it displayed breakaway corrosion kinetics after 50 h exposure. The best-behaved material both from a corrosion and hydrogen uptake point of view was Zr-2.5Nb. However, the Zr-2.5Nb oxide growth rate was still excessive and beyond the current CANDU design allowance. Similar coupons, coated with Cr, were also tested. The coated layer effectively prevented oxidation of the coupons except on the edges, where the coating was thinner and had some flaws. In addition, the Cr-coated Zr-2.5Nb coupons had the lowest deuterium pickup of all the alloys tested and showed no signs of accelerated or non- uniform corrosion. CANDU–CANada Deuterium Uranium is a registered trademark of Atomic Energy of Canada Ltd. 2 CW-124680-CONF-001 UNRESTRICTED - ILLIMITÉ 1.0 INTRODUCTION In a nuclear power plant, increasing thermodynamic efficiency and simplifying plant design are the two major ways of reducing unit energy cost. To increase the thermodynamic efficiency above 40%, the use of high-pressure supercritical water at 500 C and above, as the heat transport fluid (HTF), has been suggested [1,2].
    [Show full text]