EXAM III Material PART 1 CHEMICAL EQUILIBRIUM Chapter 14 I Dynamic Equilibrium I
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Excitation Temperature, Degree of Ionization of Added Iron Species, and Electron Density in an Exploding Thin Film Plasma
SpectmchimiccrACIO. Vol. MB. No. II. Pp.10814096. 1981. 0584-8547/81/111081-16SIZ.CNI/O Printedin Great Britain. PerpmonPress Ltd. Excitation temperature, degree of ionization of added iron species, and electron density in an exploding thin film plasma S. Y. SUH* and R. D. SACKS Department of Chemistry, University of Michigan, Ann Arbor, Ml 48109, U.S.A. (Received 7 April 1981) Abstract-Time and spatially resolved spectra of a cylindrically symmetric exploding thin film plasma were obtained with a rotating mirror camera and astigmatic imaging. These spectra were deconvoluted to obtain relative spectral emissivity profiles for nine Fe(H) and two Fe(I) lines. The effective (electronic) excitation temperature at various positions in the plasma and at various times during the first current halfcycle was computed from the Fe(H) emissivity values using the Boltzmann graphical method. The Fe(II)/Fe(I) emissivity ratios together with the temperature were used to determine the degree of ionization of Fe. Finally, the electron density was estimated from the Saha equilibrium. Electronic excitation temperatures range from lO,OOO-15,OOOKnear the electrode surface at peak discharge current to 700&10.000K at 6-10 mm above the electrode surface at the first current zero. Corresponding electron densities range from 10’7-10u cm-’ at peak current to 10’~-10’6cm-3 near zero current. Error propagation and criteria for thermodynamic equilibrium are discussed. 1. IN-~R~DU~~ION THE HIGH-TEMPERATURE plasmas produced by the rapid electrical vaporization of Ag thin films recently have been used as atomization cells and excitation sources for the direct determination of selected elements in micro-size powder samples [ 11. -
Basic Design Data, of Column for Absorption Of
j833 Index – a acetyl radical 741 breakthrough curves for H2S adsorption on a absorption 108 acid aerosols 567 molecular sieve 132, 133 – activity and activity coefficients, in acid–base catalyzed reactions 11 – calculation of lads,ideal, HTZ, and LUB chloroform 111 acid catalyst 11 based on breakthrough curves 135 – basic design data, of column for absorption acidity 10 – capillary condensation of CO2 in water 116 acid-catalyzed reaction 652 –– and adsorption/desorption hysteresis 126 – Bunsen absorption coefficient 110 acid-soluble polymers 653 – competitive 128 – – fi chemical absorption of CO2 in N- acrolein 30, 476, 476, 479, 481, 483, 701 design of a xed-bed adsorption process 131 methyldiethanolamine 112, 113 acrylamide 28, 29, 487 – design of processes 130–135 – CO2 in water, and subsequent bicarbonate acrylic acid 140, 466, 467, 479, 481–483 – desorption 131 formation 110 acrylonitrile 462, 466, 467, 486–487 – dissociative 128 – design of columns 113–116 activation energy 24, 34, 201, 203, 215, 711 – equilibrium of a binary system on zeolite 128 – equilibria of chemical absorption 108 – apparent activation energy of diffusion – estimation of slope of breakthrough curve 132 – equilibria of physical absorption, processes 229, 230, 232 – height of mass transfer zone HTZ 132 comparison 109 – for chain transfer 807 – hysteresis loop during – fl – –– gas velocity and ooding of absorption correlation between activation energy and adsorption and desorption of N2 in a column 115 reaction enthalpy for a reversible cylindrical pore 127 – height -
Characteristics of Chemical Equilibrium
Characteristics of Chemical Equilibrium Chapter 14: Chemical Equilibrium © 2008 Brooks/Cole 1 © 2008 Brooks/Cole 2 Equilibrium is Dynamic Equilibrium is Independent of Direction of Approach Reactants convert to products N2(g) + 3 H2(g) 2 NH3(g) a A + b B c C + d D Species do not stop forming OR being destroyed Rate of formation = rate of removal Concentrations are constant. © 2008 Brooks/Cole 3 © 2008 Brooks/Cole 4 Equilibrium and Catalysts The Equilibrium Constant For the 2-butene isomerization: H3C CH3 H3C H C=C C=C H H H CH3 At equilibrium: rate forward = rate in reverse An elementary reaction, so: kforward[cis] = kreverse[trans] © 2008 Brooks/Cole 5 © 2008 Brooks/Cole 6 1 The Equilibrium Constant The Equilibrium Constant At equilibrium the concentrations become constant. We had: kforward[cis] = kreverse[trans] kforward [trans] or = kreverse [cis] kforward [trans] Kc = = = 1.65 (at 500 K) kreverse [cis] “c” for concentration based © 2008 Brooks/Cole 7 © 2008 Brooks/Cole 8 The Equilibrium Constant The Equilibrium Constant For a general reaction: a A + b B c C + d D [NO]2 N2(g) + O2(g) 2 NO(g) Kc = Products raised to [N2] [O2] stoichiometric powers… k [C]c [D]d forward …divided by reactants Kc = = a b kreverse [A] [B] raised to their stoichiometric [SO ] 1 2 powers 8 S8(s) + O2(g) SO2(g) Kc = [O2] © 2008 Brooks/Cole 9 © 2008 Brooks/Cole 10 Equilibria Involving Pure Liquids and Solids Equilibria in Dilute Solutions [Solid] is constant throughout a reaction. density g / L • pure solid concentration = mol. -
Laboratory 1: Chemical Equilibrium 1
1 Laboratory 1: Chemical Equilibrium 1 Reading: Olmstead and Williams, Chemistry , Chapter 14 (all sections) Purpose: The shift in equilibrium position of a chemical reaction with applied stress is determined. Introduction Chemical Equilibrium No chemical reaction goes to completion. When a reaction stops, some amount of reactants remain. For example, although we write → ← 2 CO 2 (g) 2 CO (g) + O 2 (g) (1) as though it goes entirely to products, at 2000K only 2% of the CO 2 decomposes. A chemical reaction reaches equilibrium when the concentrations of the reactants and products no longer change with time. The position of equilibrium describes the relative amounts of reactants and products that remain at the end of a chemical reaction. The position of equilibrium for reaction (1) is said to lie with the reactants, or to the left, because at equilibrium very little of the carbon dioxide has reacted. On the other hand, in the reaction → ← H2 (g) + ½ O2 (g) H2O (g) (2) the equilibrium position lies very far to the right since only very small amounts of H 2 and O 2 remain after the reaction reaches equilibrium. Since chemists often wish to maximize the yield of a reaction, it is vital to determine how to control the position of the equilibrium. The equilibrium position of a reaction may shift if an external stress is applied. The stress may be in the form of a change in temperature, pressure, or the concentration of one of the reactants or products. For example, consider a flask with an equilibrium mixture of CO 2, CO, and O 2, as in reaction (1). -
Thermodynamics of Metal Extraction
THERMODYNAMICS OF METAL EXTRACTION By Rohit Kumar 2019UGMMO21 Ritu Singh 2019UGMM049 Dhiraj Kumar 2019UGMM077 INTRODUCTION In general, a process or extraction of metals has two components: 1. Severance:produces, through chemical reaction, two or more new phases, one of which is much richer in the valuable content than others. 2. Separation : involves physical separation of one phase from the others Three types of processes are used for accomplishing severance : 1. Pyrometallurgical: Chemical reactions take place at high temperatures. 2. Hydrometallurgical: Chemical reactions carried out in aqueous media. 3. Electrometallurgical: Involves electrochemical reactions. Advantages of Pyrometallurgical processes 1. Option of using a cheap reducing agent, (such as C, CO). As a result, the unit cost is 5-10 times lower than that of the reductants used in electrolytic processes where electric power often is the reductant. 2. Enhanced reaction rates at high temperature . 3. Simplified separation of (molten) product phase at high temperature. 4. Simplified recovery of precious metals ( Au,Ag,Cu) at high temperature. 5. Ability to shift reaction equilibria by changing temperatures. THERMODYNAMICS The Gibbs free energy(G) , of the system is the energy available in the system to do work . It is relevant to us here, because at constant temperature and pressure it considers only variables contained within the system . 퐺 = 퐻 − 푇푆 Here, T is the temperature of the system S is the entropy, or disorder, of the system. H is the enthalpy of the system, defined as: 퐻 = 푈 + 푃푉 Where U is the intern energy , P is the pressure and V is the volume. If the system is changed by a small amount , we can differentiate the above functions: 푑퐺 = 푑퐻 − 푇푑푆 − 푆푑푇 And 푑퐻 = 푑푈 − 푃푑푉 + 푉푑푃 From the first law, 푑푈 = 푑푞 − 푑푤 And from second law, 푑푆 = 푑푞/푇 We see that, 푑퐺 = 푑푞 − 푑푤 + 푃푑푉 + 푉푑푃 − 푇푑푆 − 푆푑푇 푑퐺 = −푑푤 + 푃푑푉 + 푉푑푃 − 푆푑푇 (푑푤 = 푃푑푉) 푑퐺 = 푉푑푃 − 푆푑푇 The above equations show that if the temperature and pressure are kept constant, the free energy does not change. -
Thermodynamic and Kinetic Investigation of a Chemical Reaction-Based Miniature Heat Pump Scott M
Purdue University Purdue e-Pubs CTRC Research Publications Cooling Technologies Research Center 2012 Thermodynamic and Kinetic Investigation of a Chemical Reaction-Based Miniature Heat Pump Scott M. Flueckiger Purdue University Fabien Volle Laboratoire des Sciences des Procédés et des Matériaux S V. Garimella Purdue University, [email protected] Rajiv K. Mongia Intel Corporation Follow this and additional works at: http://docs.lib.purdue.edu/coolingpubs Flueckiger, Scott M.; Volle, Fabien; Garimella, S V.; and Mongia, Rajiv K., "Thermodynamic and Kinetic Investigation of a Chemical Reaction-Based Miniature Heat Pump" (2012). CTRC Research Publications. Paper 182. http://dx.doi.org/http://dx.doi.org/10.1016/j.enconman.2012.04.015 This document has been made available through Purdue e-Pubs, a service of the Purdue University Libraries. Please contact [email protected] for additional information. Thermodynamic and Kinetic Investigation of a Chemical Reaction-Based Miniature Heat Pump* Scott M. Flueckiger1, Fabien Volle2, Suresh V. Garimella1**, Rajiv K. Mongia3 1 Cooling Technologies Research Center, an NSF I/UCRC School of Mechanical Engineering and Birck Nanotechnology Center 585 Purdue Mall, Purdue University West Lafayette, Indiana 47907-2088 USA 2 Laboratoire des Sciences des Procédés et des Matériaux (LSPM, UPR 3407 CNRS), Université Paris XIII, 99 avenue J. B. Clément, 93430 Villetaneuse, France 3 Intel Corporation Santa Clara, California 95054 USA * Submitted for publication in Energy Conversion and Management ** Author to who correspondence should be addressed: (765) 494-5621, [email protected] Abstract Representative reversible endothermic chemical reactions (paraldehyde depolymerization and 2-proponal dehydrogenation) are theoretically assessed for their use in a chemical heat pump design for compact thermal management applications. -
Anal Chem 458.309A Week 5.Pdf
§ Verify this behavior algebraically using the reaction quotient, Q § In one particular equilibrium state of this system, à the following concentrations exist: § Suppose that the equilibrium is disturbed by adding dichromate to the 2- solution to increase the concentration of [Cr2O7 ] from 0.10 to 0.20 M. à In what direction will the reaction proceed to reach equilibrium? § Because Q > K à the reaction must go to the left to decrease the numerator and increase the denominator, until Q = K § If a reaction is at equilibrium and products are added (or reactants are removed), à the reaction goes to the left. § If a reaction is at equilibrium and reactants are added (or products are removed), à the reaction goes to the right § The effect of temperature on K: § The term eΔS°/R is independent of T à ΔS is constant at least over a limited temperature range § If ΔHo is positive, à The term e-ΔH°/RT increases with increasing temperature § If ΔHo is negative, à The term e-ΔH°/RT decreases with increasing temperature § The effect of temperature on K: § If the temperature is raised, à The equilibrium constant of an endothermic reaction (ΔHo>0) increases à The equilibrium constant of an exothermic reaction (Δho<0) decreases § If the temperature is raised, à an endothermic reaction is favored § If the temperature is raised, then heat is added to the system. à The reaction proceeds to partially offset this heat à an endothermic reaction à Le Châtelier’s principle Solubility product § The equilibrium constant for the reaction in which a solid salt dissolves to give its constituent ions in solution. -
Answer Key Chapter 16: Standard Review Worksheet – + 1
Answer Key Chapter 16: Standard Review Worksheet – + 1. H3PO4(aq) + H2O(l) H2PO4 (aq) + H3O (aq) + + NH4 (aq) + H2O(l) NH3(aq) + H3O (aq) 2. When we say that acetic acid is a weak acid, we can take either of two points of view. Usually we say that acetic acid is a weak acid because it doesn’t ionize very much when dissolved in water. We say that not very many acetic acid molecules dissociate. However, we can describe this situation from another point of view. We could say that the reason acetic acid doesn’t dissociate much when we dissolve it in water is because the acetate ion (the conjugate base of acetic acid) is extremely effective at holding onto protons and specifically is better at holding onto protons than water is in attracting them. + – HC2H3O2 + H2O H3O + C2H3O2 Now what would happen if we had a source of free acetate ions (for example, sodium acetate) and placed them into water? Since acetate ion is better at attracting protons than is water, the acetate ions would pull protons out of water molecules, leaving hydroxide ions. That is, – – C2H3O2 + H2O HC2H3O2 + OH Since an increase in hydroxide ion concentration would take place in the solution, the solution would be basic. Because acetic acid is a weak acid, the acetate ion is a base in aqueous solution. – – 3. Since HCl, HNO3, and HClO4 are all strong acids, we know that their anions (Cl , NO3 , – and ClO4 ) must be very weak bases and that solutions of the sodium salts of these anions would not be basic. -
Ionization Balance in EBIT and Tokamak Plasmas N
Ionization balance in EBIT and tokamak plasmas N. J. Peacock, R. Barnsley, M. G. O’Mullane, M. R. Tarbutt, D. Crosby et al. Citation: Rev. Sci. Instrum. 72, 1250 (2001); doi: 10.1063/1.1324755 View online: http://dx.doi.org/10.1063/1.1324755 View Table of Contents: http://rsi.aip.org/resource/1/RSINAK/v72/i1 Published by the American Institute of Physics. Related Articles Bragg x-ray survey spectrometer for ITER Rev. Sci. Instrum. 83, 10E126 (2012) Novel energy resolving x-ray pinhole camera on Alcator C-Mod Rev. Sci. Instrum. 83, 10E526 (2012) Measurement of electron temperature of imploded capsules at the National Ignition Facility Rev. Sci. Instrum. 83, 10E121 (2012) South pole bang-time diagnostic on the National Ignition Facility (invited) Rev. Sci. Instrum. 83, 10E119 (2012) Temperature diagnostics of ECR plasma by measurement of electron bremsstrahlung Rev. Sci. Instrum. 83, 073111 (2012) Additional information on Rev. Sci. Instrum. Journal Homepage: http://rsi.aip.org Journal Information: http://rsi.aip.org/about/about_the_journal Top downloads: http://rsi.aip.org/features/most_downloaded Information for Authors: http://rsi.aip.org/authors Downloaded 08 Aug 2012 to 194.81.223.66. Redistribution subject to AIP license or copyright; see http://rsi.aip.org/about/rights_and_permissions REVIEW OF SCIENTIFIC INSTRUMENTS VOLUME 72, NUMBER 1 JANUARY 2001 Ionization balance in EBIT and tokamak plasmas N. J. Peacock,a) R. Barnsley,b) and M. G. O’Mullane Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon, Oxon OX14 3DB, United Kingdom M. R. Tarbutt, D. Crosby, and J. D. Silver The Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom J. -
1. Disposition and Pharmacokinetics
1. DISPOSITION AND PHARMACOKINETICS The disposition and pharmacokinetics of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and related compounds have been investigated in several species and under various exposure conditions. Several reviews on this subject focus on TCDD and related halogenated aromatic hydrocarbons (Neal et al., 1982; Gasiewicz et al., 1983a; Olson et al., 1983; Birnbaum, 1985; van den Berg et al., 1994). The relative biological and toxicological potency of TCDD and related compounds depends not only on the affinity of these compounds for the aryl hydrocarbon receptor (AhR), but on the species-, strain-, and congener-specific pharmacokinetics of these compounds (Neal et al., 1982; Gasiewicz et al., 1983a; Olson et al., 1983; Birnbaum, 1985; van den Berg et al., 1994, DeVito and Birnbaum, 1995). 2,3,7,8-TCDD and other similar compounds discussed here are rapidly absorbed into the body and slowly eliminated, making body burden (bioaccumulation) a reliable indicator of time- integrated exposure and absorbed dose. Because of the slow elimination kinetics, it will be shown in this section that lipid or blood concentrations, which are often measured, are in dynamic equilibrium with other tissue compartments in the body, making the overall body burden and tissue disposition relatively easy to estimate. Finally, it will be shown that body burdens can be correlated with adverse health effects (Hardell et al., 1995; Leonards et al., 1995), further leading to the choice of body burden as the optimal indicator of absorbed dose and potential effects. 1.1. ABSORPTION/BIOAVAILABILITY FOLLOWING EXPOSURE Gastrointestinal, dermal, and transpulmonary absorptions represent potential routes for human exposure to this class of persistent environmental contaminants. -
Main Criteria: AP Chemistry Course Description Secondary Criteria: Jove Subject: Science Grade: 9-12 Correlation Options: Show Correlated Adopted: 2013
Main Criteria: AP Chemistry Course Description Secondary Criteria: JoVE Subject: Science Grade: 9-12 Correlation Options: Show Correlated Adopted: 2013 Outline Level 1 AP.C.1. Big Idea 1: The chemical elements are fundamental building materials of matter, and all matter can be understood in terms of arrangements of atoms. These atoms retain their identity in chemical reactions. Outline Level 2 EU.1.A. All matter is made of atoms. There are a limited number of types of atoms; these are the elements. Outline Level 3 EK.1.A.1. Molecules are composed of specific combinations of atoms; different molecules are composed of combinations of different elements and of combinations of the same elements in differing amounts and proportions. Outline Level 4 1.A.1.a. The average mass of any large number of atoms of a given element is always the same for a given element. JoVE • Freezing-Point Depression to Determine an Unknown Compound • Introduction to Mass Spectrometry • MALDI-TOF Mass Spectrometry • Tandem Mass Spectrometry Outline Level 4 1.A.1.b. A pure sample contains particles (or units) of one specific atom or molecule; a mixture contains particles (or units) of more than one specific atom or molecule. JoVE • Calibration Curves • Capillary Electrophoresis (CE) • Chromatography-Based Biomolecule Purification Methods • Column Chromatography • Conducting Reactions Below Room Temperature • Cyclic Voltammetry (CV) • Degassing Liquids with Freeze-Pump-Thaw Cycling • Density Gradient Ultracentrifugation • Determining the Density of a Solid and Liquid -
Drugs and Acid Dissociation Constants Ionisation of Drug Molecules Most Drugs Ionise in Aqueous Solution.1 They Are Weak Acids Or Weak Bases
Drugs and acid dissociation constants Ionisation of drug molecules Most drugs ionise in aqueous solution.1 They are weak acids or weak bases. Those that are weak acids ionise in water to give acidic solutions while those that are weak bases ionise to give basic solutions. Drug molecules that are weak acids Drug molecules that are weak bases where, HA = acid (the drug molecule) where, B = base (the drug molecule) H2O = base H2O = acid A− = conjugate base (the drug anion) OH− = conjugate base (the drug anion) + + H3O = conjugate acid BH = conjugate acid Acid dissociation constant, Ka For a drug molecule that is a weak acid The equilibrium constant for this ionisation is given by the equation + − where [H3O ], [A ], [HA] and [H2O] are the concentrations at equilibrium. In a dilute solution the concentration of water is to all intents and purposes constant. So the equation is simplified to: where Ka is the acid dissociation constant for the weak acid + + Also, H3O is often written simply as H and the equation for Ka is usually written as: Values for Ka are extremely small and, therefore, pKa values are given (similar to the reason pH is used rather than [H+]. The relationship between pKa and pH is given by the Henderson–Hasselbalch equation: or This relationship is important when determining pKa values from pH measurements. Base dissociation constant, Kb For a drug molecule that is a weak base: 1 Ionisation of drug molecules. 1 Following the same logic as for deriving Ka, base dissociation constant, Kb, is given by: and Ionisation of water Water ionises very slightly.