Enthalpy of Fusion References
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High Temperature Enthalpies of the Lead Halides
HIGH TEMPERATURE ENTHALPIES OF THE LEAD HALIDES: ENTHALPIES AND ENTROPIES OF FUSION APPROVED: Graduate Committee: Major Professor Committee Member Min fessor Committee Member X Committee Member UJ. Committee Member Committee Member Chairman of the Department of Chemistry Dean or the Graduate School HIGH TEMPERATURE ENTHALPIES OF THE LEAD HALIDES: ENTHALPIES AND ENTROPIES OF FUSION DISSERTATION Presented to the Graduate Council of the North Texas State University in Partial Fulfillment of the Requirements For the Degree of DOCTOR OF PHILOSOPHY By Clarence W, Linsey, B. S., M. S, Denton, Texas June, 1970 ACKNOWLEDGEMENT This dissertation is based on research conducted at the Oak Ridge National Laboratory, Oak Ridge, Tennessee, which is operated by the Uniofl Carbide Corporation for the U. S. Atomic Energy Commission. The author is also indebted to the Oak Ridge Associated Universities for the Oak Ridge Graduate Fellowship which he held during the laboratory phase. 11 TABLE OF CONTENTS Page LIST OF TABLES iv LIST OF ILLUSTRATIONS v Chapter I. INTRODUCTION . 1 Lead Fluoride Lead Chloride Lead Bromide Lead Iodide II. EXPERIMENTAL 11 Reagents Fusion-Filtration Method Encapsulation of Samples Equipment and Procedure Bunsen Ice Calorimeter Computer Programs Shomate Method Treatment of Data Near the Melting Point Solution Calorimeter Heat of Solution Calculations III. RESULTS AND DISCUSSION 41 Lead Fluoride Variation in Heat Contents of the Nichrome V Capsules Lead Chloride Lead Bromide Lead Iodide Summary BIBLIOGRAPHY ...... 98 in LIST OF TABLES Table Pa8e I. High-Temperature Enthalpy Data for Cubic PbE2 Encapsulated in Gold 42 II. High-Temperature Enthalpy Data for Cubic PbF2 Encapsulated in Molybdenum 48 III. -
Molecular Dynamics Simulation Studies of Physico of Liquid
MD Simulation of Liquid Pentane Isomers Bull. Korean Chem. Soc. 1999, Vol. 20, No. 8 897 Molecular Dynamics Simulation Studies of Physico Chemical Properties of Liquid Pentane Isomers Seng Kue Lee and Song Hi Lee* Department of Chemistry, Kyungsung University, Pusan 608-736, Korea Received January 15, 1999 We have presented the thermodynamic, structural and dynamic properties of liquid pentane isomers - normal pentane, isopentane, and neopentane - using an expanded collapsed atomic model. The thermodynamic prop erties show that the intermolecular interactions become weaker as the molecular shape becomes more nearly spherical and the surface area decreases with branching. The structural properties are well predicted from the site-site radial, the average end-to-end distance, and the root-mean-squared radius of gyration distribution func tions. The dynamic properties are obtained from the time correlation functions - the mean square displacement (MSD), the velocity auto-correlation (VAC), the cosine (CAC), the stress (SAC), the pressure (PAC), and the heat flux auto-correlation (HFAC) functions - of liquid pentane isomers. Two self-diffusion coefficients of liq uid pentane isomers calculated from the MSD's via the Einstein equation and the VAC's via the Green-Kubo relation show the same trend but do not coincide with the branching effect on self-diffusion. The rotational re laxation time of liquid pentane isomers obtained from the CAC's decreases monotonously as branching increas es. Two kinds of viscosities of liquid pentane isomers calculated from the SAC and PAC functions via the Green-Kubo relation have the same trend compared with the experimental results. The thermal conductivity calculated from the HFAC increases as branching increases. -
Functionalized Aromatics Aligned with the Three Cartesian Axes: Extension of Centropolyindane Chemistry*
Pure Appl. Chem., Vol. 78, No. 4, pp. 749–775, 2006. doi:10.1351/pac200678040749 © 2006 IUPAC Functionalized aromatics aligned with the three Cartesian axes: Extension of centropolyindane chemistry* Dietmar Kuck‡ Fakultät für Chemie, Universität Bielefeld, Universitätsstraße 25, D-33615 Bielefeld, Germany Abstract: The unique geometrical features and structural potential of the centropolyindanes, a complete family of novel, 3D polycyclic aromatic hydrocarbons, are discussed with respect to the inherent orthogonality of their arene units. Thus, the largest member of the family, centrohexaindane, a topologically nonplanar hydrocarbon, is presented as a “Cartesian hexa- benzene”, because each of its six benzene units is stretched into one of the six directions of the Cartesian space. This feature is discussed on the basis of the X-ray crystal structures of centrohexaindane and two lower members of the centropolyindane family, viz. the parent tribenzotriquinacenes. Recent progress in multiple functionalization and extension of the in- dane wings of selected centropolyindanes is reported, including several highly efficient six- and eight-fold C–C cross-coupling reactions. Some particular centropolyindane derivatives are presented, such as the first twelve-fold functionalized centrohexaindane and a tribenzo- triquinacene bearing three mutually orthogonal phenanthroline groupings at its molecular pe- riphery. Challenges to further extend the arene peripheries of the tribenzotriquinacenes and fenestrindanes to give, eventually, graphite cuttings bearing a central bowl- or saddle-shaped center are outlined, as is the hypothetical generation of a “giant” nanocube consisting of eight covalently bound tribenzotriquinacene units. Along these lines, our recent discovery of a re- lated, solid-state supramolecular cube, containing eight molecules of a particular tri- bromotrinitrotribenzotriquinacene of the same absolute configuration, is presented for the first time. -
Chapter 11 Liquids, Solids, and Phase Changes
Lecture Presentation Chapter 11 Liquids, Solids, and Phase Changes 11.1, 11.2, 11.3, 11.4, 11.15, 11.17, 11.26, 11.30, 11.32, 11.40, 11.42, 11.60, 11.82, 11.116 John E. McMurry Robert C. Fay Properties of Liquids Viscosity: The measure of a liquid’s resistance to flow (higher intermolecular force, higher viscosity) Surface Tension: The resistance of a liquid to spread out and increase its surface area (forms beads) (higher intermolecular force, higher surface tension) Properties of Liquids low intermolecular force – low viscosity, low surface tension high intermolecular force – high viscosity, high surface tension HW 11.1 Properties of Liquids high intermolecular force – high viscosity, high surface tension For the following molecules which has the higher intermolecular force, viscosity and surface tension ? (LD structure, VSEPRT, dipole of molecule) (if the molecules are in the liquid state) a. CHCl3 vs CH4 b. H2O vs H2 (changed from handout) c. N Cl3 vs N H Cl2 Phase Changes between Solids, Liquids, and Gases Phase Change (State Change): A change in the physical state but not the chemical identity of a substance Fusion (melting): solid to liquid Freezing: liquid to solid Vaporization: liquid to gas Condensation: gas to liquid Sublimation: solid to gas Deposition: gas to solid Phase Changes between Solids, Liquids, and Gases Enthalpy – add heat to system Entropy – add randomness to system Phase Changes between Solids, Liquids, and Gases Heat (Enthalpy) of Fusion (DHfusion ): The amount of energy required to overcome enough intermolecular forces to convert a solid to a liquid Heat (Enthalpy) of Vaporization (DHvap): The amount of energy required to overcome enough intermolecular forces to convert a liquid to a gas HW 11.2: Phase Changes between Solids, Liquids, & Gases DHfusion solid to a liquid DHvap liquid to a gas At phase change (melting, boiling, etc) : DG = DH – TDS & D G = zero (bc 2 phases in equilibrium) DH = TDS o a. -
2.6 Physical Properties of Alkanes
02_BRCLoudon_pgs4-4.qxd 11/26/08 8:36 AM Page 70 70 CHAPTER 2 • ALKANES PROBLEMS 2.12 Represent each of the following compounds with a skeletal structure. (a) CH3 CH3CH2CH2CH" CH C(CH3)3 L L "CH3 (b) ethylcyclopentane 2.13 Name the following compounds. (a) (b) CH3 CH2CH3 H3C 2.14 How many hydrogens are in an alkane of n carbons containing (a) two rings? (b) three rings? (c) m rings? 2.15 How many rings does an alkane have if its formula is (a) C8H10? (b) C7H12? Explain how you know. 2.6 PHYSICAL PROPERTIES OF ALKANES Each time we come to a new family of organic compounds, we’ll consider the trends in their melting points, boiling points, densities, and solubilities, collectively referred to as their phys- ical properties. The physical properties of an organic compound are important because they determine the conditions under which the compound is handled and used. For example, the form in which a drug is manufactured and dispensed is affected by its physical properties. In commercial agriculture, ammonia (a gas at ordinary temperatures) and urea (a crystalline solid) are both very important sources of nitrogen, but their physical properties dictate that they are handled and dispensed in very different ways. Your goal should not be to memorize physical properties of individual compounds, but rather to learn to predict trends in how physical properties vary with structure. A. Boiling Points The boiling point is the temperature at which the vapor pressure of a substance equals atmos- pheric pressure (which is typically 760 mm Hg). -
Adsorption of Nitrogen, Neopentane, N-Hexane, Benzene and Methanol for the Evaluation of Pore Sizes in Silica Grades of MCM-41
Microporous and Mesoporous Materials 47 >2001) 323±337 www.elsevier.com/locate/micromeso Adsorption of nitrogen, neopentane, n-hexane, benzene and methanol for the evaluation of pore sizes in silica grades of MCM-41 M.M.L. Ribeiro Carrott a,*, A.J.E. Candeias a, P.J.M. Carrott a, P.I. Ravikovitch b, A.V. Neimark b, A.D. Sequeira c a Department of Chemistry, University of Evora, Colegio Luõs Antonio Verney, Rua Roma~o Romalho 59, 7000-671 Evora, Portugal b Center for Modeling and Characterization of Nanoporous Materials, TRI/Princeton, 601 Prospect Avenue, Princeton, NJ 08542-0625, USA c Department of Physics, Nuclear and Technological Institute, 2686-953 Sacavem, Portugal Received 26 February 2001; received in revised form 7 June 2001; accepted 11 June 2001 Abstract Nitrogen, neopentane, n-hexane, benzene and methanol adsorption isotherms were determined on ®ve samples of silica grade MCM-41 with dierent pore sizes and a comparison of dierent methods for evaluating the pore size was carried out. With nitrogen we found a remarkably good agreement between the results obtained from the non-local density functional theory and geometric methods, with corresponding values obtained by the two methods diering by less than 0.05 nm. On the other hand, the results con®rm ®ndings seen before by other workers that, in order to obtain reliable values of pore radii by the hydraulic method, it is necessary to use a cross-sectional area of nitrogen in the monolayer smaller than the normally assumed value of 0.162 nm2. In addition, it was found that the eective pore volume obtained with the four organic adsorptives was almost constant while the value obtained from nitrogen ad- sorption data was always higher. -
Cryometric Determination of the Enthalpy of Fusion of Sodium Cryolite
Cryometric determination of the enthalpy of fusion of sodium cryolite M. MALINOVSKÝ Department of Chemical Technology of Inorganic Substances, Slovak Technical University, CS-812 37Bratislava Received 30 July 1982 Accepted for publication 22 August 1983 Using the method of classical thermal analysis a part of the liquidus of sodium cryolite in the system Na3AlF6—Na3FS04 was measured in the compo sition range 0—5 mole % Na3FS04. On the basis of these results the molar enthalpy of fusion of cryolite was calculated. It was found that AHf(Na3AlFft) = = 115.4 kJ mol"1; error in this result was estimated to be ±4.9 %. Методом классического термического анализа измерена часть ликви дуса натриевого криолита в системе Na3AlF6—Na3FS04 в интервале кон центраций 0—5 мол. % Na3FS04. На основании этих результатов рассчи тана мольная энтальпия плавления криолита. Найдено, что 1 AH,(Na3AlF6) = 115,4 кДж моль" ; точность этого результата ±4,9 %. Literature survey and theoretical Knowledge of the enthalpy of fusion of sodium hexafluoroaluminate Na3AlF6 (cryolite) is important both from theoretical and practical points of view. For example, it is needed at calculation of the thermal and energy balance and/or the thermal inertia of aluminium cells (the electrolyte contains about 90 mass % of Na3AlF6). The most precise values of the molar enthalpy of fusion AHf(i) of chemical substances can be generally obtained from calorimetric measurements. However, when we deal with substances having higher melting temperature and which are also unstable and very corrosive the calorimetric determination of the quantity AHf(i) can be less reliable. In the case of cryolite Roth and Bertram [1] found from the calorimetric 1 1 measurements ÄH,(Na3 A1F6) = 16.64 kcal mol" = 69.62 kJ mol" . -
Crystal Structure Transformations in Binary Halides
1 A UNITED STATES DEPARTMENT OF A111D3 074^50 IMMERCE JBLICAT10N NSRDS—NBS 41 HT°r /V\t Co^ NSRDS r #C£ DM* ' Crystal Structure Transformations in Binary Halides u.s. ARTMENT OF COMMERCE National Bureau of -QC*-| 100 US73 ho . 4 1^ 72. NATIONAL BUREAU OF STANDARDS 1 The National Bureau of Standards was established by an act of Congress March 3, 1901. The Bureau's overall goal is to strengthen and advance the Nation’s science and technology and facilitate their effective application for public benefit. To this end, the Bureau conducts research and provides: (1) a basis for the Nation’s physical measure- ment system, (2) scientific and technological services for industry and government, (3) a technical basis for equity in trade, and (4) technical services to promote public safety. The Bureau consists of the Institute for Basic Standards, the Institute for Materials Research, the Institute for Applied Technology, the Center for Computer Sciences and Technology, and the Office for Information Programs. THE INSTITUTE FOR BASIC STANDARDS provides the central basis within the United States of a complete and consistent system of physical measurement; coordinates that system with measurement systems of other nations; and furnishes essential services leading to accurate and uniform physical measurements throughout the Nation’s scien- tific community, industry, and commerce. The Institute consists of a Center for Radia- tion Research, an Office of Measurement Services and the following divisions: Applied Mathematics—Electricity—Heat—Mechanics—Optical Physics—Linac Radiation 2—Nuclear Radiation 2—Applied Radiation 2—Quantum Electronics 3— Electromagnetics 3—Time and Frequency 3—Laboratory Astrophysics 3—Cryo- 3 genics . -
FACT SHEET Pentane, All Isomers
FACT SHEET Pentane, All Isomers CAS Numbers: n-Pentane: 109-66-0; Isopentane: 78-78-4; Neopentane: 463-82-1 This fact sheet provides a summary of the Development Support Document (DSD) created by the TCEQ Toxicology Division (TD) for the development of Regulatory Guidelines (ESLs, AMCVs and ReVs) for ambient exposure to this chemical. For more detailed information, please see the DSD or contact the TD by phone (1-877-992-8370) or e-mail ([email protected]). What is pentane? Pentane is a colorless, volatile and flammable liquid with a sweet or gasoline-like odor. Pentane consists of three isomers: n-pentane, isopentane, and neopentane. n-Pentane is an ingredient of crude oil and a component of the condensate from natural gas production. It is primarily obtained from the processing of crude oil. n-Pentane is used as a component of gasoline blends, as an aerosol propellant, as a blowing agent for foams, and as a solvent. Isopentane is also used as a blowing agent, and neopentane is used in the manufacture of butyl rubber. How is pentane released into ambient air? Pentane can be released into the air from industrial uses or production plants and from natural gas production. It is also released to the environment during its use in adhesives and glues. Pentane released to the environment is expected to volatilize to the atmosphere, where it will undergo photochemical oxidation reactions. How can pentane affect my health? Permitted levels of pentane should not cause adverse health and welfare effects. Pentane produces minor lung irritation. Based on animal studies, inhalation of extremely high concentrations of pentane (i.e., concentrations above the lower explosive limit of 14,000 ppm) may affect the nervous system or cause irritation of the nose and throat. -
Thermodynamic Temperature
Thermodynamic temperature Thermodynamic temperature is the absolute measure 1 Overview of temperature and is one of the principal parameters of thermodynamics. Temperature is a measure of the random submicroscopic Thermodynamic temperature is defined by the third law motions and vibrations of the particle constituents of of thermodynamics in which the theoretically lowest tem- matter. These motions comprise the internal energy of perature is the null or zero point. At this point, absolute a substance. More specifically, the thermodynamic tem- zero, the particle constituents of matter have minimal perature of any bulk quantity of matter is the measure motion and can become no colder.[1][2] In the quantum- of the average kinetic energy per classical (i.e., non- mechanical description, matter at absolute zero is in its quantum) degree of freedom of its constituent particles. ground state, which is its state of lowest energy. Thermo- “Translational motions” are almost always in the classical dynamic temperature is often also called absolute tem- regime. Translational motions are ordinary, whole-body perature, for two reasons: one, proposed by Kelvin, that movements in three-dimensional space in which particles it does not depend on the properties of a particular mate- move about and exchange energy in collisions. Figure 1 rial; two that it refers to an absolute zero according to the below shows translational motion in gases; Figure 4 be- properties of the ideal gas. low shows translational motion in solids. Thermodynamic temperature’s null point, absolute zero, is the temperature The International System of Units specifies a particular at which the particle constituents of matter are as close as scale for thermodynamic temperature. -
Safety Data Sheet
Bayville Chemical Supply Company Inc. 70-G East Jefryn Boulevard, Deer Park, New York 11729 USA Telephone: 631-586-4309 E-Mail: [email protected] Fax: 631-254-5591 SAFETY DATA SHEET NEOPENTANE 1. CHEMICAL PRODUCT PRODUCT NAME: 2,2-DIMETHYLPROPANE SYNONYMS: Neopentane PRODUCT USE: Synthetic, analytical chemistry EMERGENCY TELEPHONE NUMBERS: CHEMTEL: (800) 255-3924 or 813-248-0585 2. HAZARD INDENTIFICATION OSHA/HCS STATUS: This material is considered hazardous by the OSHA Hazard Communication standard (29 CFR 1910.1200). CLASSIFICATION OF THE SUBSTANCE: Flammable Gas – Category 1 Gases Under Pressure – Compressed gas Aquatic Hazard (Long-Term) – Category 1 GHS LABEL ELEMENTS: HAZARD PICTOGRAMS: SIGNAL WORD: Danger HAZARD STATEMENTS: Extremely flammable gas. May form explosive mixture with air. Contains gas under pressure; may explode if heated. May displace oxygen and cause rapid suffocation. Very toxic to aquatic life with long lasting effects. PRECAUTIONARY STATEMENTS: GENERAL: Read and follow all safety data sheets before use. Read label before use. Keep out of reach of children. If medical advice is needed, have product container or label at hand. Close valve after each use and when empty. Use equipment rated for cylinder pressure. Do not open valve until connected to equipment prepared for use. Use back flow preventive device in the piping. Use only equipment of compatible materials of construction. Approach suspected leak area with caution. PREVENTION: Never put cylinders into unventilated areas of passenger vehicles. Keep away from heat, sparks, open flames and hot surfaces. No Smoking. Avoid release to the environment. Use and store only outdoors or in a well ventilated place. -
Enthalpy of Sublimation in the Study of the Solid State of Organic Compounds
J. Phys. Chem. B 2005, 109, 18055-18060 18055 Enthalpy of Sublimation in the Study of the Solid State of Organic Compounds. Application to Erythritol and Threitol A. J. Lopes Jesus, Luciana I. N. Tome´, M. Ermelinda Euse´bio,* and J. S. Redinha Department of Chemistry, UniVersity of Coimbra, 3004-535, Coimbra, Portugal ReceiVed: March 30, 2005; In Final Form: July 5, 2005 The enthalpies of sublimation of erythritol and L-threitol have been determined at 298.15 K by calorimetry. The values obtained for the two diastereomers differ from one another by 17 kJ mol-1. An interpretation of these results is based on the decomposition of this thermodynamic property in a term coming from the intermolecular interactions of the molecules in the crystal (∆intH°) and another one related with the conformational change of the molecules on going from the crystal lattice to the most stable forms in the gas phase (∆confH°). This last term was calculated from the values of the enthalpy of the molecules in the gas state and of the enthalpy of the isolated molecules with the crystal conformation. Both quantities were obtained by density functional theory (DFT) calculations at the B3LYP/6-311G++(d,p) level of theory. The results obtained in this study show that the most important contribution to the differences observed in the enthalpy of sublimation are the differences in the enthalpy of conformational change (13 kJ mol-1) rather than different intermolecular forces exhibited in the solid phase. This is explained by the lower enthalpy of threitol in the gas phase relative to erythritol, which is attributed to the higher strength of the intramolecular hydrogen bonds in the former.