Unit IV Outiline
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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 -
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. -
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 -
Theoretical Problem Icho 2019
Candidate: AAA-1 THEORETICAL EXAM Making science together! 2019-07-26 51st IChO – Theoretical Exam 1 Candidate: AAA-1 General instructions This theoretical exam booklet contains 60 pages. You may begin writing as soon as the Start command is given. You have 5 hours to complete the exam. All results and answers must be clearly written in pen in their respective designed areas on the exam papers. Answers written outside the answer boxes will not be graded. If you need scratch paper, use the backside of the exam sheets. Remember that nothing outside the designed areas will be graded. Use only the pen and calculator provided. The official English version of the exam booklet is available upon request and serves for clarification only. If you need to leave the exam room (to use the toilet or have a snack), wave the corresponding IChO card. An exam supervisor will come to accompany you. For multiple-choice questions: if you want to change your answer, fill the answer box completely and then make a new empty answer box next to it. The supervisor will announce a 30-minute warning before the Stop command. You must stop your work immediately when the Stop command is announced. Failure to stop writing by ½ minute or longer will lead to nullification of your theoretical exam. After the Stop command has been given, place your exam booklet back in your exam envelope, then wait at your seat. The exam supervisor will come to seal the envelope in front of you and collect it. GOOD LUCK! 51st IChO – Theoretical Exam 2 Candidate: AAA-1 Table of Contents This theoretical exam is composed of 9 independent problems, as follows. -
Tribute to Biman Bagchi Laser Spectroscopic Groups of One of Us (G.R.F.), Paul Barbara, and Others
Special Issue Preface pubs.acs.org/JPCB Tribute to Biman Bagchi laser spectroscopic groups of one of us (G.R.F.), Paul Barbara, and others. The solvation dynamics was reported to have times scales faster than dielectric relaxation, which posed a challenge to theorists for proper explanations. Just before joining IISc, Bagchi, in collaboration with G.R.F. and David Oxtoby, had developed a theory of dipolar solvation using a continuum model of the solvent and a frequency dependent dielectric function. The theory predicted a solvation time that was faster than the dielectric relaxation time of the solvent, thus providing an explanation of the experimentally observed fast relaxation of the time dependent solvation energy. The continuum theory was subsequently generalized by Bagchi and co-workers in many different directions such as incorporation of multi-Debye relaxation, non-Debye relaxation, inhomogeneity of the medium around a solute, etc. Still, being based on continuum models, all these extensions lacked the molecularity of the solvent. Besides, these theories considered only the rotational motion of solvent molecules because the dynamics came through the frequency Photo by S. R. Prasad dependence of the long wavelength dielectric function. Micro- rofessor Biman Bagchi has made pivotal contributions to the scopic theories based on molecular solvent models also started P area of dynamics of chemical and biological systems in an coming from other groups; however, these microscopic theories academic career spanning more than three decades. He has been also included only the rotational motion of solvent molecules. a great teacher and mentor for a large number of young These rotation-only microscopic theories predicted an average theoretical physical chemists of India and a creative and insightful solvation time that was longer than the long-wavelength fi collaborator with leading scientists worldwide. -
Sequencing Instruction in Chemistry: Simulation Or Traditional First?
SEQUENCING INSTRUCTION IN CHEMISTRY: SIMULATION OR TRADITIONAL FIRST? by Sharmila Pillay B.Sc., The University of South Pacific, 1994 B.Ed., The University of British Columbia, 1999 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF ARTS in THE FACULTY OF GRADUATE STUDIES (Science Education) THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) October 2010 ©Sharmila Pillay, 2010 ABSTRACT The purpose of this study is to investigate how a technology-enhanced lesson based on the principles of model-based teaching and learning can contribute to student understanding of two challenging topics in chemistry: Le Chatelier’s Principle and Chemical Equilibrium. A computer simulation program was utilized that contained multiple digital representations, such as: a chemical formula view, a slider view, a graph view, a description view, a prediction view, a molecular view and a dynamic analogy view. The study also addressed the sequencing of instruction, changing when computer simulation was introduced in two chemistry 12 classes (n=46). One class of 22 students received instruction in a traditional form (lecture, labs) and then interacted with the simulation and the other class of 24 students interacted with simulations first and then received a traditional form of instruction. Both the classes participated in a pre-test, mid-test, post-test, surveys and interviews designed to assess students’ conceptual understanding of chemical equilibrium. Statistical analysis of the tests revealed that a computer simulation such as Technology-Enhanced Model-Based Science (TEMBS) promoted understanding by supporting the generation of more scientifically accurate models of chemical equilibrium. Secondly, there was a significant improvement in test results of students who received instruction in a traditional form first and then interacted with simulations compared with students who interacted with simulations first and then received traditional instruction. -
Elektrochemia Simr 02 En
Electrochemistry course Electrolyte - reminder ACME Faculty, EHVE course Liquid or solid that conducts electricity B.Sc. Studies, II year, IV semester by means of its ions. Ions can move when they have freedom Leszek Niedzicki, PhD, DSc, Eng. of movement. That freedom can be provided by molten salt (ionic liquid) , specific structure of solid enabling ionic mobility or (most commonly) solvation of ions in the solution by solvent Fundamentals of ionics molecules (and as a result - shielding them from counter-ions and causing dissociation). 2 Solvation once more Dynamic equilibrium Disturbance of solvent structure by an ion: • It is a phenomenon observed when on a large scale (e.g. billions of billions of molecules) a statistical equilibrium A – I solvation layer (directly coordinated by a cation) is observed, i.e. mean value of a given parameter is B – II and further solvation layers (attracted steady, but individual molecules often change their electrostatically by a cation and can interact with other solvent state. molecules – e.g. through the hydrogen bonds) • In practice dynamic equilibrium is defined C – solvent structure disturbed by the cation as an equilibrium of two opposite processes, which presence in the vicinity occur at the same rate (in a given conditions). In case D – original solvent structure of solvation solvent molecules are all the time C+ joining and leaving solvation layer (e.g. are knocked A B out of it). However, mean solvent molecules C in solvation layer of a given ion stays the same. D 3 4 Dynamic equilibrium Solvent • In dissociation or solvation case dynamic • Solvent in the electrolyte formation process is equilibrium forms because solvent molecules required to solvate ions (shields them against and ions are bumping on each other association or crystal formation) and dissociate compound into ions (strength of interaction with part (and at the vessel walls) all the time (due to chaotic of the compound tears it from the other part moves, vibrations, etc. -
Raoult's Law – Partition Law
BAE 820 Physical Principles of Environmental Systems Henry’s Law - Raoult's Law – Partition law Dr. Zifei Liu Biological and Agricultural Engineering Henry's law • At a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid. Pi = KHCi • Where Pi is the partial pressure of the gaseous solute above the solution, C is the i William Henry concentration of the dissolved gas and KH (1774-1836) is Henry’s constant with the dimensions of pressure divided by concentration. KH is different for each solute-solvent pair. Biological and Agricultural Engineering 2 Henry's law For a gas mixture, Henry's law helps to predict the amount of each gas which will go into solution. When a gas is in contact with the surface of a liquid, the amount of the gas which will go into solution is proportional to the partial pressure of that gas. An equivalent way of stating the law is that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid. the solubility of gases generally decreases with increasing temperature. A simple rationale for Henry's law is that if the partial pressure of a gas is twice as high, then on the average twice as many molecules will hit the liquid surface in a given time interval, Biological and Agricultural Engineering 3 Air-water equilibrium Dissolution Pg or Cg Air (atm, Pa, mol/L, ppm, …) At equilibrium, Pg KH = Caq Water Caq (mol/L, mole ratio, ppm, …) Volatilization Biological and Agricultural Engineering 4 Various units of the Henry’s constant (gases in water at 25ºC) Form of K =P/C K =C /P K =P/x K =C /C equation H, pc aq H, cp aq H, px H, cc aq gas Units L∙atm/mol mol/(L∙atm) atm dimensionless -3 4 -2 O2 769 1.3×10 4.26×10 3.18×10 -4 4 -2 N2 1639 6.1×10 9.08×10 1.49×10 -2 3 CO2 29 3.4×10 1.63×10 0.832 Since all KH may be referred to as Henry's law constants, we must be quite careful to check the units, and note which version of the equation is being used. -
The Equilibrium Constant
Chapter 15: Chemical Equilibrium Key topics: Equilibrium Constant Calculating Equilibrium Concentrations The Concept of Equilibrium Consider the reaction k1 A ⌦ B k 1 − At equilibrium there is no net change in [A] or [B], namely d[A] d[B] =0= dt dt But A molecules can react to form B, and B molecules can react to form A, if the forwards and backwards rates are equal. k1[A] = k 1[B] − This is because d[A] = k1[A] + k 1[B] dt − − At the molecular level, typically the reactions do not stop. Initially there is net evaporation of liquid, but after dynamic equilibrium is established, the rate of evaporation = rate of condensation. (from chemtutorial.net) Consider the reaction N2O4(g) 2NO2(g) Begin with only N2O4 (colorless). Begin with only NO2 (brown). 2 The forward rate = kf [N2O4]; the reverse rate = kr [NO2] (the elementary reactions are the same as the overall reaction) In both cases equilibrium is established after some time. The Equilibrium Constant At equilibrium the forwards and reverse rates are equal 2 2 kf [NO2]eq kf [N2O4]eq = kr[NO2]eq = = Kc ) kr [N2O4]eq Kc is the equilibrium constant (the “c” here stands for concentration). In general, to write an equilibrium constant o products over reactants o exponents are the coefficients from the balanced reaction Magnitude of the Equilibrium Constant o If Kc >> 1, products are favored (rxn nearly complete). o If Kc << 1, reactants are favored (rxn hardly proceeds). o If Kc is close to 1, the system contains comparable amounts of products and reactants. -
Measurement of Henry's Law Constant Of
View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by DSpace@IZTECH Institutional Repository MEASUREMENT OF HENRY’S LAW CONSTANT OF ORGANOCHLORINATED PESTICIDES A Thesis Submitted to the Graduate School of Engineering and Sciences of zmir Institute of Technology in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE in Chemical Engineering by Serdar Özer July 2005 ZMR We approve the thesis of Serdar ÖZER Date of Signature ................................................................ 26 June 2005 Assist. Prof. Dr. Aysun SOFUOLU Supervisor Department of Chemical Engineering zmir Institute of Technology ................................................................. 26 June 2005 Assoc. Prof. Dr. Funda TIHMINLIOLU Department of Chemical Engineering zmir Institute of Technology ............................................................... 26 June 2005 Assoc. Prof. Dr. Mustafa ODABAI Department of Environmental Engineering 9 September University ................................................................. 26 June 2005 Prof. Dr. Devrim BALKÖSE Head of Department zmir Institute of Technology .............................................................. Assoc. Prof. Dr. Semahat ÖZDEMR Head of the Graduate School ACKNOWLEDGEMENTS I would like to express my gratitude to my advisor, Assist. Prof. Aysun Sofuolu, for her guidance, patience and tolerance. I am grateful to Assoc. Prof. Mustafa Odabaı for his valuable suggestions and guidance. I also would like to give my thanks to Assoc. Prof. Funda Tıhmınlıolu for being in my jury and reccomendations for the corrections. I would like to acknowledge deeply to Banu Çetin, Sevde Bozacıolu, Can Aksakal, and Özge Malay for their encouragement and supports during my study. I would like to appreciate my very special thanks to my girlfriend Baak for her love. ABSTRACT Most of the semi-volatile organic compounds, which are environmentally important, are subject to long range atmospheric transport due to their chemical and physical properties. -
Chemistry 130 Acid and Base Equilibria
Chemistry 130 Acid and Base equilibria Dr. John F. C. Turner 409 Buehler Hall [email protected] Chemistry 130 Acids and bases The Brùnsted-Lowry definition of an acid states that any material that produces the hydronium ion is an acid. A Brùnsted-Lowry acid is a proton donor: + - HA H2 Ol H3 Oaq Aaq + + The hydronium ion, H 3 O a q or H a q has the same structure as ammonia. It is pyramidal and has one lone pair on O. Chemistry 130 Acids and bases The Brùnsted-Lowry definition of a base states that any material that accepts a proton is a base. A Brùnsted-Lowry base is a proton acceptor: - - + Baq H2 Ol HOaq BHaq In aqueous solution, a base forms the hydroxide ion: Chemistry 130 Conjugate acids and bases For any acid-base reaction, the original acid and base are complemented by the conjugate acid and conjugate base: - + NH3aq H2Ol HOaq NH4aq On the RHS, On the LHS, Water is the proton donor Hydroxide ion is the proton acceptor Ammonia is the proton acceptor Ammonium ion is the proton donor Water and hydroxide ion are conjugate acid and base Ammonia and ammonium ion are also conjugate acid and base Chemistry 130 Conjugate acids and bases The anion of every acid is the conjugate base of that acid The cation of every base is the conjugate acid of that base Acid-base conjugates exist due to the dynamic equilibrium that exists in solution. - + NH3aq H2Ol HOaq NH4aq - + NH3aq H2Ol HOaq NH4aq Chemistry 130 Acid and base constants We use equilibrium constants to define the position of equilibrium and to reflect the dynamic nature of the system.