Changes of State
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Physical Model for Vaporization
Physical model for vaporization Jozsef Garai Department of Mechanical and Materials Engineering, Florida International University, University Park, VH 183, Miami, FL 33199 Abstract Based on two assumptions, the surface layer is flexible, and the internal energy of the latent heat of vaporization is completely utilized by the atoms for overcoming on the surface resistance of the liquid, the enthalpy of vaporization was calculated for 45 elements. The theoretical values were tested against experiments with positive result. 1. Introduction The enthalpy of vaporization is an extremely important physical process with many applications to physics, chemistry, and biology. Thermodynamic defines the enthalpy of vaporization ()∆ v H as the energy that has to be supplied to the system in order to complete the liquid-vapor phase transformation. The energy is absorbed at constant pressure and temperature. The absorbed energy not only increases the internal energy of the system (U) but also used for the external work of the expansion (w). The enthalpy of vaporization is then ∆ v H = ∆ v U + ∆ v w (1) The work of the expansion at vaporization is ∆ vw = P ()VV − VL (2) where p is the pressure, VV is the volume of the vapor, and VL is the volume of the liquid. Several empirical and semi-empirical relationships are known for calculating the enthalpy of vaporization [1-16]. Even though there is no consensus on the exact physics, there is a general agreement that the surface energy must be an important part of the enthalpy of vaporization. The vaporization diminishes the surface energy of the liquid; thus this energy must be supplied to the system. -
LATENT HEAT of FUSION INTRODUCTION When a Solid Has Reached Its Melting Point, Additional Heating Melts the Solid Without a Temperature Change
LATENT HEAT OF FUSION INTRODUCTION When a solid has reached its melting point, additional heating melts the solid without a temperature change. The temperature will remain constant at the melting point until ALL of the solid has melted. The amount of heat needed to melt the solid depends upon both the amount and type of matter that is being melted. Therefore: Q = ML Eq. 1 f where Q is the amount of heat absorbed by the solid, M is the mass of the solid that was melted and Lf is the latent heat of fusion for the type of material that was melted, which is measured in J/kg, NOTE: to fuse means to melt. In this experiment the latent heat of fusion of water will be determined by using the method of mixtures ΣQ=0, or QGained +QLost =0. Ice will be added to a calorimeter containing warm water. The heat energy lost by the water and calorimeter does two things: 1. It melts the ice; 2. It warms the water formed by the melting ice from zero to the final equilibrium temperature of the mixture. Heat gained + Heat lost = 0 Heat needed to melt ice + Heat needed to warm the melt water + Heat lost by warn water = 0 MiceLf + MiceCw (Tf - 0) + MwCw (Tf – Tw) = 0 Eq. 2. * Note: The mass of the melted water is the same as the mass of the ice. where M = mass of warm water initially in calorimeter w Mice = mass of ice and water from the melted ice Cw = specific heat of water Lf = latent heat of fusion of water Tw = initial temperature water Tf = equilibrium temperature of mixture APPARATUS: Calorimeter, thermometer, balance, ice, water OBJECTIVE: To determine the latent heat of fusion of water PROCEDURE: 1. -
VISCOSITY of a GAS -Dr S P Singh Department of Chemistry, a N College, Patna
Lecture Note on VISCOSITY OF A GAS -Dr S P Singh Department of Chemistry, A N College, Patna A sketchy summary of the main points Viscosity of gases, relation between mean free path and coefficient of viscosity, temperature and pressure dependence of viscosity, calculation of collision diameter from the coefficient of viscosity Viscosity is the property of a fluid which implies resistance to flow. Viscosity arises from jump of molecules from one layer to another in case of a gas. There is a transfer of momentum of molecules from faster layer to slower layer or vice-versa. Let us consider a gas having laminar flow over a horizontal surface OX with a velocity smaller than the thermal velocity of the molecule. The velocity of the gaseous layer in contact with the surface is zero which goes on increasing upon increasing the distance from OX towards OY (the direction perpendicular to OX) at a uniform rate . Suppose a layer ‘B’ of the gas is at a certain distance from the fixed surface OX having velocity ‘v’. Two layers ‘A’ and ‘C’ above and below are taken into consideration at a distance ‘l’ (mean free path of the gaseous molecules) so that the molecules moving vertically up and down can’t collide while moving between the two layers. Thus, the velocity of a gas in the layer ‘A’ ---------- (i) = + Likely, the velocity of the gas in the layer ‘C’ ---------- (ii) The gaseous molecules are moving in all directions due= to −thermal velocity; therefore, it may be supposed that of the gaseous molecules are moving along the three Cartesian coordinates each. -
Equation of State for Benzene for Temperatures from the Melting Line up to 725 K with Pressures up to 500 Mpa†
High Temperatures-High Pressures, Vol. 41, pp. 81–97 ©2012 Old City Publishing, Inc. Reprints available directly from the publisher Published by license under the OCP Science imprint, Photocopying permitted by license only a member of the Old City Publishing Group Equation of state for benzene for temperatures from the melting line up to 725 K with pressures up to 500 MPa† MONIKA THOL ,1,2,* ERIC W. Lemm ON 2 AND ROLAND SPAN 1 1Thermodynamics, Ruhr-University Bochum, Universitaetsstrasse 150, 44801 Bochum, Germany 2National Institute of Standards and Technology, 325 Broadway, Boulder, Colorado 80305, USA Received: December 23, 2010. Accepted: April 17, 2011. An equation of state (EOS) is presented for the thermodynamic properties of benzene that is valid from the triple point temperature (278.674 K) to 725 K with pressures up to 500 MPa. The equation is expressed in terms of the Helmholtz energy as a function of temperature and density. This for- mulation can be used for the calculation of all thermodynamic properties. Comparisons to experimental data are given to establish the accuracy of the EOS. The approximate uncertainties (k = 2) of properties calculated with the new equation are 0.1% below T = 350 K and 0.2% above T = 350 K for vapor pressure and liquid density, 1% for saturated vapor density, 0.1% for density up to T = 350 K and p = 100 MPa, 0.1 – 0.5% in density above T = 350 K, 1% for the isobaric and saturated heat capaci- ties, and 0.5% in speed of sound. Deviations in the critical region are higher for all properties except vapor pressure. -
Geometrical Vortex Lattice Pinning and Melting in Ybacuo Submicron Bridges Received: 10 August 2016 G
www.nature.com/scientificreports OPEN Geometrical vortex lattice pinning and melting in YBaCuO submicron bridges Received: 10 August 2016 G. P. Papari1,*, A. Glatz2,3,*, F. Carillo4, D. Stornaiuolo1,5, D. Massarotti5,6, V. Rouco1, Accepted: 11 November 2016 L. Longobardi6,7, F. Beltram2, V. M. Vinokur2 & F. Tafuri5,6 Published: 23 December 2016 Since the discovery of high-temperature superconductors (HTSs), most efforts of researchers have been focused on the fabrication of superconducting devices capable of immobilizing vortices, hence of operating at enhanced temperatures and magnetic fields. Recent findings that geometric restrictions may induce self-arresting hypervortices recovering the dissipation-free state at high fields and temperatures made superconducting strips a mainstream of superconductivity studies. Here we report on the geometrical melting of the vortex lattice in a wide YBCO submicron bridge preceded by magnetoresistance (MR) oscillations fingerprinting the underlying regular vortex structure. Combined magnetoresistance measurements and numerical simulations unambiguously relate the resistance oscillations to the penetration of vortex rows with intermediate geometrical pinning and uncover the details of geometrical melting. Our findings offer a reliable and reproducible pathway for controlling vortices in geometrically restricted nanodevices and introduce a novel technique of geometrical spectroscopy, inferring detailed information of the structure of the vortex system through a combined use of MR curves and large-scale simulations. Superconductors are materials in which below the superconducting transition temperature, Tc, electrons form so-called Cooper pairs, which are bosons, hence occupying the same lowest quantum state1. The wave function of this Cooper condensate has a fixed phase. Hence, by virtue of the uncertainty principle, the number of Cooper pairs in the condensate is undefined. -
Determination of the Identity of an Unknown Liquid Group # My Name the Date My Period Partner #1 Name Partner #2 Name
Determination of the Identity of an unknown liquid Group # My Name The date My period Partner #1 name Partner #2 name Purpose: The purpose of this lab is to determine the identity of an unknown liquid by measuring its density, melting point, boiling point, and solubility in both water and alcohol, and then comparing the results to the values for known substances. Procedure: 1) Density determination Obtain a 10mL sample of the unknown liquid using a graduated cylinder Determine the mass of the 10mL sample Save the sample for further use 2) Melting point determination Set up an ice bath using a 600mL beaker Obtain a ~5mL sample of the unknown liquid in a clean dry test tube Place a thermometer in the test tube with the sample Place the test tube in the ice water bath Watch for signs of crystallization, noting the temperature of the sample when it occurs Save the sample for further use 3) Boiling point determination Set up a hot water bath using a 250mL beaker Begin heating the water in the beaker Obtain a ~10mL sample of the unknown in a clean, dry test tube Add a boiling stone to the test tube with the unknown Open the computer interface software, using a graph and digit display Place the temperature sensor in the test tube so it is in the unknown liquid Record the temperature of the sample in the test tube using the computer interface Watch for signs of boiling, noting the temperature of the unknown Dispose of the sample in the assigned waste container 4) Solubility determination Obtain two small (~1mL) samples of the unknown in two small test tubes Add an equal amount of deionized into one of the samples Add an equal amount of ethanol into the other Mix both samples thoroughly Compare the samples for solubility Dispose of the samples in the assigned waste container Observations: The unknown is a clear, colorless liquid. -
Viscosity of Gases References
VISCOSITY OF GASES Marcia L. Huber and Allan H. Harvey The following table gives the viscosity of some common gases generally less than 2% . Uncertainties for the viscosities of gases in as a function of temperature . Unless otherwise noted, the viscosity this table are generally less than 3%; uncertainty information on values refer to a pressure of 100 kPa (1 bar) . The notation P = 0 specific fluids can be found in the references . Viscosity is given in indicates that the low-pressure limiting value is given . The dif- units of μPa s; note that 1 μPa s = 10–5 poise . Substances are listed ference between the viscosity at 100 kPa and the limiting value is in the modified Hill order (see Introduction) . Viscosity in μPa s 100 K 200 K 300 K 400 K 500 K 600 K Ref. Air 7 .1 13 .3 18 .5 23 .1 27 .1 30 .8 1 Ar Argon (P = 0) 8 .1 15 .9 22 .7 28 .6 33 .9 38 .8 2, 3*, 4* BF3 Boron trifluoride 12 .3 17 .1 21 .7 26 .1 30 .2 5 ClH Hydrogen chloride 14 .6 19 .7 24 .3 5 F6S Sulfur hexafluoride (P = 0) 15 .3 19 .7 23 .8 27 .6 6 H2 Normal hydrogen (P = 0) 4 .1 6 .8 8 .9 10 .9 12 .8 14 .5 3*, 7 D2 Deuterium (P = 0) 5 .9 9 .6 12 .6 15 .4 17 .9 20 .3 8 H2O Water (P = 0) 9 .8 13 .4 17 .3 21 .4 9 D2O Deuterium oxide (P = 0) 10 .2 13 .7 17 .8 22 .0 10 H2S Hydrogen sulfide 12 .5 16 .9 21 .2 25 .4 11 H3N Ammonia 10 .2 14 .0 17 .9 21 .7 12 He Helium (P = 0) 9 .6 15 .1 19 .9 24 .3 28 .3 32 .2 13 Kr Krypton (P = 0) 17 .4 25 .5 32 .9 39 .6 45 .8 14 NO Nitric oxide 13 .8 19 .2 23 .8 28 .0 31 .9 5 N2 Nitrogen 7 .0 12 .9 17 .9 22 .2 26 .1 29 .6 1, 15* N2O Nitrous -
Guide to Understanding Condensation
Guide to Understanding Condensation The complete Andersen® Owner-To-Owner™ limited warranty is available at: www.andersenwindows.com. “Andersen” is a registered trademark of Andersen Corporation. All other marks where denoted are marks of Andersen Corporation. © 2007 Andersen Corporation. All rights reserved. 7/07 INTRODUCTION 2 The moisture that suddenly appears in cold weather on the interior We have created this brochure to answer questions you may have or exterior of window and patio door glass can block the view, drip about condensation, indoor humidity and exterior condensation. on the floor or freeze on the glass. It can be an annoying problem. We’ll start with the basics and offer solutions and alternatives While it may seem natural to blame the windows or doors, interior along the way. condensation is really an indication of excess humidity in the home. Exterior condensation, on the other hand, is a form of dew — the Should you run into problems or situations not covered in the glass simply provides a surface on which the moisture can condense. following pages, please contact your Andersen retailer. The important thing to realize is that if excessive humidity is Visit the Andersen website: www.andersenwindows.com causing window condensation, it may also be causing problems elsewhere in your home. Here are some other signs of excess The Andersen customer service toll-free number: 1-888-888-7020. humidity: • A “damp feeling” in the home. • Staining or discoloration of interior surfaces. • Mold or mildew on surfaces or a “musty smell.” • Warped wooden surfaces. • Cracking, peeling or blistering interior or exterior paint. -
Chapter 3 Equations of State
Chapter 3 Equations of State The simplest way to derive the Helmholtz function of a fluid is to directly integrate the equation of state with respect to volume (Sadus, 1992a, 1994). An equation of state can be applied to either vapour-liquid or supercritical phenomena without any conceptual difficulties. Therefore, in addition to liquid-liquid and vapour -liquid properties, it is also possible to determine transitions between these phenomena from the same inputs. All of the physical properties of the fluid except ideal gas are also simultaneously calculated. Many equations of state have been proposed in the literature with either an empirical, semi- empirical or theoretical basis. Comprehensive reviews can be found in the works of Martin (1979), Gubbins (1983), Anderko (1990), Sandler (1994), Economou and Donohue (1996), Wei and Sadus (2000) and Sengers et al. (2000). The van der Waals equation of state (1873) was the first equation to predict vapour-liquid coexistence. Later, the Redlich-Kwong equation of state (Redlich and Kwong, 1949) improved the accuracy of the van der Waals equation by proposing a temperature dependence for the attractive term. Soave (1972) and Peng and Robinson (1976) proposed additional modifications of the Redlich-Kwong equation to more accurately predict the vapour pressure, liquid density, and equilibria ratios. Guggenheim (1965) and Carnahan and Starling (1969) modified the repulsive term of van der Waals equation of state and obtained more accurate expressions for hard sphere systems. Christoforakos and Franck (1986) modified both the attractive and repulsive terms of van der Waals equation of state. Boublik (1981) extended the Carnahan-Starling hard sphere term to obtain an accurate equation for hard convex geometries. -
Chapter 3 Bose-Einstein Condensation of an Ideal
Chapter 3 Bose-Einstein Condensation of An Ideal Gas An ideal gas consisting of non-interacting Bose particles is a ¯ctitious system since every realistic Bose gas shows some level of particle-particle interaction. Nevertheless, such a mathematical model provides the simplest example for the realization of Bose-Einstein condensation. This simple model, ¯rst studied by A. Einstein [1], correctly describes important basic properties of actual non-ideal (interacting) Bose gas. In particular, such basic concepts as BEC critical temperature Tc (or critical particle density nc), condensate fraction N0=N and the dimensionality issue will be obtained. 3.1 The ideal Bose gas in the canonical and grand canonical ensemble Suppose an ideal gas of non-interacting particles with ¯xed particle number N is trapped in a box with a volume V and at equilibrium temperature T . We assume a particle system somehow establishes an equilibrium temperature in spite of the absence of interaction. Such a system can be characterized by the thermodynamic partition function of canonical ensemble X Z = e¡¯ER ; (3.1) R where R stands for a macroscopic state of the gas and is uniquely speci¯ed by the occupa- tion number ni of each single particle state i: fn0; n1; ¢ ¢ ¢ ¢ ¢ ¢g. ¯ = 1=kBT is a temperature parameter. Then, the total energy of a macroscopic state R is given by only the kinetic energy: X ER = "ini; (3.2) i where "i is the eigen-energy of the single particle state i and the occupation number ni satis¯es the normalization condition X N = ni: (3.3) i 1 The probability -
Companion Q&A Fact Sheet: What Mars Reveals About Life in Our
What Mars Reveals about Life in Our Universe Companion Q&A Fact Sheet Educators from the Smithsonian’s Air and Space and Natural History Museums assembled this collection of commonly asked questions about Mars to complement the Smithsonian Science How webinar broadcast on March 3, 2021, “What Mars Reveals about Life in our Universe.” Continue to explore Mars and your own curiosities with these facts and additional resources: • NASA: Mars Overview • NASA: Mars Robotic Missions • National Air and Space Museum on the Smithsonian Learning Lab: “Wondering About Astronomy Together” Guide • National Museum of Natural History: A collection of resources for teaching about Antarctic Meteorites and Mars 1 • Smithsonian Science How: “What Mars Reveals about Life in our Universe” with experts Cari Corrigan, L. Miché Aaron, and Mariah Baker (aired March 3, 2021) Mars Overview How long is Mars’ day? Mars takes 24 hours and 38 minutes to spin around once, so its day is very similar to Earth’s. How long is Mars’ year? Mars takes 687 days, almost two Earth years, to complete one orbit around the Sun. How far is Mars from Earth? The distance between Earth and Mars changes as both planets move around the Sun in their orbits. At its closest, Mars is just 34 million miles from the Earth; that’s about one third of Earth’s distance from the Sun. On the day of this program, March 3, 2021, Mars was about 135 million miles away, or four times its closest distance. How far is Mars from the Sun? Mars orbits an average of 141 million miles from the Sun, which is about one-and-a-half times as far as the Earth is from the Sun. -
Fish Technology Glossary
Glossary of Fish Technology Terms A Selection of Terms Compiled by Kevin J. Whittle and Peter Howgate Prepared under contract to the Fisheries Industries Division of the Food and Agriculture Organization of the United Nations 6 December 2000 Last updated: February 2002 Kevin J. Whittle 1 GLOSSARY OF FISH TECHNOLOGY TERMS [Words highlighted in bold in the text of an entry refer to another entry. Words in parenthesis are alternatives.] Abnormalities Attributes of the fish that are not found in the great majority of that kind of fish. For example: atypical shapes; overall or patchy discolorations of skin or of fillet; diseased conditions; atypical odours or flavours. Generally, the term should be used for peculiarities present in the fish at the time of capture or harvesting, or developing very soon after; peculiarities arising during processing should be considered as defects. Acetic acid Formal chemical name, ethanoic acid. An organic acid of formula CH3.COOH. It is the main component, 3-6%, other than water, of vinegar. Used in fish technology in preparation of marinades. Acid curing See Marinating Actomyosin A combination of the two main proteins, actin and myosin, present in all muscle tissues. Additive A chemical added to a food to affect its properties. Objectives of including additives in a product include: increased stability during storage; inhibition of growth of microorganisms or production of microbial toxins; prevention or reduction of formation of off-flavours; improved sensory properties, particularly colours and appearance, affecting acceptability to the consumer; improved properties related to preparation and processing of food, for example, ability to create stable foams or emulsions, or to stabilise or thicken sauces.