GROUP 7 Halogen the Group of Halogens Is the Only Periodic Table
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Chlorine Stable Isotopes in Sedimentary Systems: Does Size Matter?
Chlorine stable isotopes in sedimentary systems: does size matter? Max Coleman Jet Propulsion Laboratory, Caltech, Pasadena, California, USA ABSTRACT: Stable isotope abundances vary because of size (atomic mass) differences. The chlorine stable isotope system was one of the first described theoretically, but had a slow, disappointment-strewn develop- ment, relative to other elements. Method improvement gave only small, but significant, differences (-1 %.) in compositions of geological materials. Eventually, brines and groundwater chlorides gave larger differences (-5%0). Physical processes like diffusion and adsorption, probably are the main controls of groundwater com- positions. In contrast, the processes producing brine compositions are still enigmatic and need further work for full understanding. Recent work on anthropogenic groundwater contaminants (chlorinated aliphatic hy- drocarbons and perchlorate) shows variations resulting from manufacturing processes; implying possibilities of tracing sources. However, they are subject to microbial degradation, producing much larger fractionations (115%0),but therefore offering better possibility of monitoring natural attenuation. So atomic size is important to give isotopic fractionation and the size of fractionation matters, allowing observation of otherwise unde- tectable processes. lecular and atomic weights by weighing the gases and relating them to the weight of hydrogen. All 1 INTRODUCTION atomic weights were integer multiples the weight of This paper aims to give a short and selective -
8.7 Hydrofluoric Acid 8.7.1 General
8.7 Hydrofluoric Acid 8.7.1 General5-6 Hydrogen fluoride (HF) is listed as a Title III Hazardous Air Pollutant. Hydrogen fluoride is produced in 2 forms, as anhydrous hydrogen fluoride and as aqueous hydrofluoric acid. The predominant form manufactured is hydrogen fluoride, a colorless liquid or gas that fumes on contact with air and is water soluble. Traditionally, hydrofluoric acid has been used to etch and polish glass. Currently, the largest use for HF is in aluminum production. Other HF uses include uranium processing, petroleum alkylation, and stainless steel pickling. Hydrofluoric acid is also used to produce fluorocarbons used in aerosol sprays and in refrigerants. Although fluorocarbons are heavily regulated due to environmental concerns, other applications for fluorocarbons include manufacturing of resins, solvents, stain removers, surfactants, and pharmaceuticals. 8.7.2 Process Description1-3,6 Hydrofluoric acid is manufactured by the reaction of acid-grade fluorspar (CaF2) with sulfuric acid (H2SO4) as shown below: → CaF2 H2SO4 CaSO4 2HF A typical HF plant is shown schematically in Figure 8.7-1. The endothermic reaction requires 30 to 60 minutes in horizontal rotary kilns externally heated to 200 to 250°C (390 to 480°F). Dry fluorspar ("spar") and a slight excess of sulfuric acid are fed continuously to the front end of a stationary prereactor or directly to the kiln by a screw conveyor. The prereactor mixes the components prior to charging to the rotary kiln. Calcium sulfate (CaSO4) is removed through an air lock at the opposite end of the kiln. The gaseous reaction products—hydrogen fluoride and excess H2SO4 from the primary reaction and silicon tetrafluoride (SiF4), sulfur dioxide (SO2), carbon dioxide (CO2), and water produced in secondary reactions—are removed from the front end of the kiln along with entrained particulate. -
Arxiv:2001.06745V2 [Nucl-Th] 6 Jun 2021 Osrit Nteeuto Fsaeo Eto-Ihncermat Nuclear [5–9]
Neutron drip line of Z =9 − 11 isotopic chains Rong An,1 Guo-Fang Shen,1 Shi-Sheng Zhang,1, ∗ and Li-Sheng Geng1, 2, 3, 4, † 1School of Physics, Beihang University, Beijing 100191, China 2Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beihang University, Beijing 100191, China 3Beijing Advanced Innovation Center for Big Data-based Precision Medicine, Beihang University, Beijing100191, China 4School of Physics and Microelectronics, Zhengzhou University, Zhengzhou, Henan 450001, China A recent experimental breakthrough identified the last bound neutron-rich nuclei in fluorine and neon isotopes. Based on this finding, we perform a theoretical study of Z = 9, 10, 11, 12 isotopes in the relativistic mean field (RMF) model. The mean field parameters are assumed from the PK1 parameterization, and the pairing correlation is described by the particle number conservation BCS (FBCS) method recently formulated in the RMF model. We show that the FBCS approach plays an essential role in reproducing experimental results of fluorine and neon isotopes. Furthermore, we predict 39Na and 40Mg to be the last bound neutron-rich nuclei in sodium and magnesium isotopes. I. INTRODUCTION Properties of neutron-rich nuclei, in particular, the location of the neutron drip line, play an important role not only in understanding nuclear stability with respect to the isospin in hereto unexplored regions of the nuclear chart [1], but also in numerous related scientific issues of current interests. For instance, the r-process nucleosynthesis of heavy elements in stellar evolution crucially depends on the values of beta decay rates and neutron capture cross sections in neutron-rich nuclei that do not exist in terrestrial conditions [2–4]. -
Is There an Acid Strong Enough to Dissolve Glass? – Superacids
ARTICLE Is there an acid strong enough to dissolve glass? – Superacids For anybody who watched cartoons growing up, the word unit is based on how acids behave in water, however as acid probably springs to mind images of gaping holes being very strong acids react extremely violently in water this burnt into the floor by a spill, and liquid that would dissolve scale cannot be used for the pure ‘common’ acids (nitric, anything you drop into it. The reality of the acids you hydrochloric and sulphuric) or anything stronger than them. encounter in schools, and most undergrad university Instead, a different unit, the Hammett acidity function (H0), courses is somewhat underwhelming – sure they will react is often preferred when discussing superacids. with chemicals, but, if handled safely, where’s the drama? A superacid can be defined as any compound with an People don’t realise that these extraordinarily strong acids acidity greater than 100% pure sulphuric acid, which has a do exist, they’re just rarely seen outside of research labs Hammett acidity function (H0) of −12 [1]. Modern definitions due to their extreme potency. These acids are capable of define a superacid as a medium in which the chemical dissolving almost anything – wax, rocks, metals (even potential of protons is higher than it is in pure sulphuric acid platinum), and yes, even glass. [2]. Considering that pure sulphuric acid is highly corrosive, you can be certain that anything more acidic than that is What are Superacids? going to be powerful. What are superacids? Its all in the name – super acids are intensely strong acids. -
[email protected] +1-703-527-3887 (International) Website
Date of Issue: 10 May 2016 SAFETY DATA SHEET 1. SUBSTANCE AND SOURCE IDENTIFICATION Product Identifier SRM Number: 3122 SRM Name: Hafnium (Hf) Standard Solution Other Means of Identification: Not applicable. Recommended Use of This Material and Restrictions of Use This Standard Reference Material (SRM) is intended for use as a primary calibration standard for the quantitative determination of hafnium. A unit of SRM 3122 consists of 50 mL of an acidified aqueous solution prepared gravimetrically to contain a known mass fraction of hafnium in a polyethylene bottle sealed in an aluminized bag. The solution contains volume fractions of nitric acid at approximately 1 % to 10 % and hydrofluoric acid at approximately 1 % to 2 %. Company Information National Institute of Standards and Technology Standard Reference Materials Program 100 Bureau Drive, Stop 2300 Gaithersburg, Maryland 20899-2300 Telephone: 301-975-2200 Emergency Telephone ChemTrec: FAX: 301-948-3730 1-800-424-9300 (North America) E-mail: [email protected] +1-703-527-3887 (International) Website: http://www.nist.gov/srm 2. HAZARDS IDENTIFICATION Classification Physical Hazard: Not classified. Health Hazard: Skin Corrosion/Irritation Category 1B Serious Eye Damage/Eye Irritation Category 1 Label Elements Symbol Signal Word DANGER Hazard Statement(s) H314 Causes severe skin burns and eye damage. Precautionary Statement(s) P260 Do not breathe fumes, mists, vapors, or spray. P264 Wash hands thoroughly after handling. P280 Wear protective gloves, protective clothing, and eye protection. P301+P330+P331 If swallowed: Rinse mouth. Do NOT induce vomiting. P303+P361+P353 If on skin (or hair): Remove immediately all contaminated clothing. Rinse skin with water. -
1 9729/01/TJC Prelim/2018 [Turn Over
1 CHEMISTRY 9729/01 Paper 1 Multiple Choice 15th September 2018 1 hour Additional materials: Multiple Choice Answer Sheet Data Booklet READ THESE INSTRUCTIONS FIRST Write in soft pencil. Do not use staples, paper clips, glue or correction fluid. Write your name and Civics Group Write and shade your index number There are thirty questions on this paper. Answer all questions. For each question there are four possible answers A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet. Read the instructions on the Answer Sheet very carefully. Each correct answer will score one mark. A mark will not be deducted for a wrong answer. Any rough working should be done in this booklet. The use of an approved scientific calculator is expected, where appropriate. This document consists of 13 printed pages. 9729/01/TJC Prelim/2018 [Turn Over 2 Section A For each question there are four possible answers, A, B, C and D. Choose the one you consider correct and record your choice in soft pencil on the separate Answer Sheet (OMS). 1 Some isotopes are unstable and undergo nuclear (radioactive) reactions. In one type of reaction, an unstable nucleus assimilates an electron from an inner orbital of its electron cloud. The net effect is the conversion of a proton and an electron into a neutron. Which of the following describes this type of reaction? A 11C 12C B 111I 111Te C 76Br 75Br D 76Kr 75Br 2 Sodium hydrogencarbonate can be prepared from sodium sulfate by a three-step process: Na2SO4(s) + 4C(s) -
New Technologies for 211At Targeted Α-Therapy Research Using 211Rn and 209At
New technologies for 211At targeted α-therapy research using 211Rn and 209At Jason Raymond Crawford BSc, University of British Columbia, 2007 MSc, University of Victoria, 2010 A dissertation submitted in partial fulfilment of the requirements for the degree of Doctorate of Philosophy in the Department of Physics and Astronomy c Jason Raymond Crawford, 2016 University of Victoria All rights reserved. This dissertation may not be reproduced in whole or in part by photocopy or other means, without the permission of the author. ii New technologies for 211At targeted α-therapy research using 211Rn and 209At by Jason Raymond Crawford BSc, University of British Columbia, 2007 MSc, University of Victoria, 2010 Supervisory Committee Dr. Thomas J Ruth, Co-Supervisor Department of Physics and Astronomy Dr. Andrew Jirasek, Co-Supervisor Department of Physics and Astronomy Dr. Wayne Beckham, Committee Member Department of Physics and Astronomy Dr. Dean Karlen, Committee Member Department of Physics and Astronomy Dr. Julian Lum, Outside Member Department of Biochemistry & Microbiology iii Abstract The most promising applications for targeted α-therapy with astatine-211 (211At) in- clude treatments of disseminated microscopic disease, the major medical problem for cancer treatment. The primary advantages of targeted α-therapy with 211At are that the α-particle radiation is densely ionizing, translating to high relative biological effectiveness (RBE), and short-range, minimizing damage to surrounding healthy tissues. In addition, theranostic imaging with 123I surrogates has shown promise for developing new therapies with 211At and translating them to the clinic. Currently, Canada does not have a way of producing 211At by conventional methods because it lacks α-particle accelerators with necessary beam energy and intensity. -
Periodic Trends in the Main Group Elements
Chemistry of The Main Group Elements 1. Hydrogen Hydrogen is the most abundant element in the universe, but it accounts for less than 1% (by mass) in the Earth’s crust. It is the third most abundant element in the living system. There are three naturally occurring isotopes of hydrogen: hydrogen (1H) - the most abundant isotope, deuterium (2H), and tritium 3 ( H) which is radioactive. Most of hydrogen occurs as H2O, hydrocarbon, and biological compounds. Hydrogen is a colorless gas with m.p. = -259oC (14 K) and b.p. = -253oC (20 K). Hydrogen is placed in Group 1A (1), together with alkali metals, because of its single electron in the valence shell and its common oxidation state of +1. However, it is physically and chemically different from any of the alkali metals. Hydrogen reacts with reactive metals (such as those of Group 1A and 2A) to for metal hydrides, where hydrogen is the anion with a “-1” charge. Because of this hydrogen may also be placed in Group 7A (17) together with the halogens. Like other nonmetals, hydrogen has a relatively high ionization energy (I.E. = 1311 kJ/mol), and its electronegativity is 2.1 (twice as high as those of alkali metals). Reactions of Hydrogen with Reactive Metals to form Salt like Hydrides Hydrogen reacts with reactive metals to form ionic (salt like) hydrides: 2Li(s) + H2(g) 2LiH(s); Ca(s) + H2(g) CaH2(s); The hydrides are very reactive and act as a strong base. It reacts violently with water to produce hydrogen gas: NaH(s) + H2O(l) NaOH(aq) + H2(g); It is also a strong reducing agent and is used to reduce TiCl4 to titanium metal: TiCl4(l) + 4LiH(s) Ti(s) + 4LiCl(s) + 2H2(g) Reactions of Hydrogen with Nonmetals Hydrogen reacts with nonmetals to form covalent compounds such as HF, HCl, HBr, HI, H2O, H2S, NH3, CH4, and other organic and biological compounds. -
Lawrence Berkeley National Laboratory Recent Work
Lawrence Berkeley National Laboratory Recent Work Title PART A. AN X-RAY SPECTROMETER FOR USE IN RADIOACTIVITY MEASUREMENTS, THE L X- RAYS OF NEPTUNIUM AND PLUTONIUM. PART B. SOME LIGHTER ISOTOPES OF ASTATINE Permalink https://escholarship.org/uc/item/9ss952mr Author Barton, G.W. Publication Date 1950-05-02 eScholarship.org Powered by the California Digital Library University of California ·. l '; UCRL~67o · cy 2 UNIVERSITY OF CALIFORNIA TWO-WEEK LOAN COPY This is a Library Circulating Copy which may be borrowed for two weeks. For a personal retention copy, call Tech. Info. Division, Ext. 5545 BERKELEY, CALIFORNIA DISCLAIMER This document was prepared as an account of work sponsored by the United States Government. While this document is believed to contain correct information, neither the United States Government nor any agency thereof, nor the Regents of the University of California, nor any of their employees, makes any warranty, express or implied, or assumes any legal responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by its trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof, or the Regents of the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof or the Regents of the University of California. • .\ UCRL-670 No Distribution II]ECLASSIF~ED UNIVERSITY OF CALIFORNIA Radiation Laboratory Contract No. -
Inorganic Chemistry
AS-Level INORGANIC CHEMISTRY Q1 A mixture of the oxides of two elements of the third period is dissolved in water. The solution is approximately neutral. What could be the constituents of the mixture? A Al2O3 and MgO B Na2O and MgO C Na2O and P4O10 D SO3 and P4O10 Q2 Aluminium chloride catalyses certain reactions by forming carbocations (carbonium ions) with chloroalkanes as shown. Which property makes this reaction possible? A AlCl3 is a covalent molecule. B AlCl3 exists as the dimer Al2Cl6 in the vapour. C The aluminium atom in AlCl3 has an incomplete octet of electrons. D The chlorine atom in RCl has a vacant p orbital. Q3 What are the products of the thermal decomposition of magnesium nitrate? A magnesium nitride and oxygen B magnesium oxide and nitrogen C magnesium oxide, nitrogen and oxygen D magnesium oxide, nitrogen dioxide and oxygen Q4 Chlorine compounds show oxidation states ranging from –1 to +7. What are the reagent(s) and conditions necessary for the oxidation of elemental chlorine into a compound containing chlorine in the +5 oxidation state? A AgNO3(aq) followed by NH3(aq) at room temperature B concentrated H2SO4 at room temperature C cold dilute NaOH(aq) D hot concentrated NaOH(aq) Q5 Which gaseous hydride most readily decomposes into its elements on contact with a hot glass rod? A ammonia B hydrogen chloride C hydrogen iodide D steam Q6 Which reagent, when mixed and heated with ammonium sulphate, liberates ammonia? A aqueous bromine B dilute hydrochloric acid C limewater D acidified potassium dichromate(VI) Q7 Which pollutant -
12 Natural Isotopes of Elements Other Than H, C, O
12 NATURAL ISOTOPES OF ELEMENTS OTHER THAN H, C, O In this chapter we are dealing with the less common applications of natural isotopes. Our discussions will be restricted to their origin and isotopic abundances and the main characteristics. Only brief indications are given about possible applications. More details are presented in the other volumes of this series. A few isotopes are mentioned only briefly, as they are of little relevance to water studies. Based on their half-life, the isotopes concerned can be subdivided: 1) stable isotopes of some elements (He, Li, B, N, S, Cl), of which the abundance variations point to certain geochemical and hydrogeological processes, and which can be applied as tracers in the hydrological systems, 2) radioactive isotopes with half-lives exceeding the age of the universe (232Th, 235U, 238U), 3) radioactive isotopes with shorter half-lives, mainly daughter nuclides of the previous catagory of isotopes, 4) radioactive isotopes with shorter half-lives that are of cosmogenic origin, i.e. that are being produced in the atmosphere by interactions of cosmic radiation particles with atmospheric molecules (7Be, 10Be, 26Al, 32Si, 36Cl, 36Ar, 39Ar, 81Kr, 85Kr, 129I) (Lal and Peters, 1967). The isotopes can also be distinguished by their chemical characteristics: 1) the isotopes of noble gases (He, Ar, Kr) play an important role, because of their solubility in water and because of their chemically inert and thus conservative character. Table 12.1 gives the solubility values in water (data from Benson and Krause, 1976); the table also contains the atmospheric concentrations (Andrews, 1992: error in his Eq.4, where Ti/(T1) should read (Ti/T)1); 2) another category consists of the isotopes of elements that are only slightly soluble and have very low concentrations in water under moderate conditions (Be, Al). -
Experimental Aspects of Geoneutrino Detection: Status and Perspectives
Experimental Aspects of Geoneutrino Detection: Status and Perspectives O. Smirnov,1 1JINR, Joint Institute for Nuclear Research, Dubna, Russian Federation October 22, 2019 Abstract Neutrino geophysics, the study of the Earth's interior by measuring the fluxes of geologically produced neutrino at its surface, is a new interdisciplinary field of science, rapidly developing as a synergy between geology, geophysics and particle physics. Geoneutrinos, antineutrinos from long- lived natural isotopes responsible for the radiogenic heat flux, provide valuable information for the chemical composition models of the Earth. The calculations of the expected geoneutrino signal are discussed, together with experimental aspects of geoneutrino detection, including the description of possible backgrounds and methods for their suppression. At present, only two detectors, Borexino and KamLAND, have reached sensitivity to the geoneutrino. The experiments accumulated a set of ∼190 geoneutrino events and continue the data acquisition. The detailed description of the experiments, their results on geoneutrino detection, and impact on geophysics are presented. The start of operation of other detectors sensitive to geoneutrinos is planned for the near future: the SNO+ detector is being filled with liquid scintillator, and the biggest ever 20 kt JUNO detector is under construction. A review of the physics potential of these experiments with respect to the geoneutrino studies, along with other proposals, is presented. New ideas and methods for geoneutrino detection are reviewed. Contents 1 Introduction 2 2 Geoneutrinos and the Earth's heat 4 2.1 Long-lived radiogenic elements . 4 2.2 Radiogenic heat and geoneutrino luminosity of the Earth . 9 arXiv:1910.09321v1 [physics.geo-ph] 21 Oct 2019 3 Geoneutrino flux calculation 11 3.1 Neutrino oscillations .