Average Atomic Mass Worksheet with Answers
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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 -
Those Two Isotopes Are Chemical Identical and Can Only Be Separated by Using Their Relatively Small Difference in Mass
Exercise2. Why is it extremely difficult to separate the two isotopes of copper, 63Cu and 65Cu? Those two isotopes are chemical identical and can only be separated by using their relatively small difference in mass. Exercise 3. If a nuclear reaction adds an extra neutron to the nucleus of 57Fe (a stable isotope of iron), it produces 58Fe (another stable isotope of iron). Will this change in the nucleus affect the number and arrangement of the electrons in the atom that’s built around this nucleus? Why or why not? No: the number of electrons = number of protons (= atomic number) and this hasn’t changed. Because the number of electrons doesn’t change and the charge in the nucleus doesn’t change, the arrangement of electron orbitals (standing waves) also doesn’t change. Exercise 4: If a nuclear reaction adds an extra proton to the nucleus of 58Fe (a stable isotope of iron), it produces 59Co (a stable isotope of cobalt). Will this change in the nucleus affect the number and arrangement of the electrons in the atom that’s built around this nucleus? Why or why not? Yes: since the nuclear charge has increased, an additional electron is needed to form a neutral atom. Because of both the change in number of electrons and the stronger Coulomb attraction from the nucleus, the arrangement of electron orbitals will change. Exercise 7. When a large nucleus is split in half during an experiment at a nuclear physics lab, the result is usually two medium-size nuclei with too many neutrons to be stable. -
Cross Calibration for Using Neutron Activation Analysis with Copper Samples to Measure D-T Fusion Yields
Cross Calibration for using Neutron Activation Analysis with Copper Samples to measure D-T Fusion Yields Chad A. McCoy May 5, 2011 The University of New Mexico Department of Physics and Astronomy Undergraduate Honors Thesis Advisor: Gary W. Cooper (UNM ChNE) Daniel Finley Abstract We used a dense plasma focus with maximum neutron yield greater than 1012 neutrons per pulse as a D-T neutron source to irradiate samples of copper, praseodymium, silver, and lead, to cross- calibrate the coincidence system for using neutron activation analysis to measure total neutron yields. In doing so, we counted the lead samples using an attached plastic scintillator, due to the short half-life and single gamma decay. The copper samples were counted using two 6” NaI coincidence systems and a 3” NaI coincidence system to determine the total neutron yield. For the copper samples, we used a calibration method which we refer to as the “F factor” to calibrate the system as a whole and used this factor to determine the total neutron yield. We concluded that the most accurate measurement of the D-T fusion neutron yield using copper activation detectors is by using 3 inch diameter copper samples in a 6” NaI coincidence system. This measurement gave the most accurate results relative to the lead probe and reference samples for all the copper samples tested. Furthermore, we found that the total neutron yield as measured with the 3 inch diameter copper samples in the 6” diameter NaI systems is approximately 89 ± 10 % the total neutron yield as measured using the lead, praseodymium and silver detectors. -
Atmospheric Source Terms for the Idaho Chemical Processing Plant, 1957 – 1959
FINAL ATMOSPHERIC SOURCE TERMS FOR THE IDAHO CHEMICAL PROCESSING PLANT, 1957–1959 Contract No. 200-2002-00367 Task Order No. 1, Subtask 1 A final report to the Centers for Disease Control and Prevention Atlanta, Georgia 30335 SC&A, Inc. 6858 Old Dominion Drive, Suite 301 McLean, Virginia 22101 SENES Oak Ridge, Inc. 102 Donner Drive Oak Ridge, Tennessee 37830 Authors: Robert P. Wichner, SENES Oak Ridge, Inc. John-Paul Renier, SENES Oak Ridge, Inc. A. Iulian Apostoaei, SENES Oak Ridge, Inc. July 2005 ICPP Source Terms July 2005 TABLE OF CONTENTS EXECUTIVE SUMMARY .......................................................................................................ES-1 1.0 SCOPE AND APPROACH ............................................................................................. 1-1 1.1 Scope .................................................................................................................. 1-1 1.2 Approach.............................................................................................................. 1-1 1.2.1 Operational RaLa Releases ...................................................................... 1-1 1.2.2 Idaho Chemical Processing Plant Criticality Approach........................... 1-2 2.0 THE RADIOACTIVE LANTHANUM (RaLa) PROCESS ............................................ 2-1 2.1 Background .......................................................................................................... 2-1 2.1.1 Requirement ............................................................................................ -
Radioactive Isotopes of Copper 578 (1936)
1110 NATURE jUNE 26, 1937 axis, no water is being frozen or melted with change 10h.l,5.8• Madsen has directed attention to the in temperature. When the curve is vertical with confusion over these periods and gives the half-life respect to the temperature axis, pure water is being period of the copper obtained from zinc as 17h!. frozen or melted. When the curve is inclined to the Leo Szilard, of the Clarendon Laboratory, Oxford, temperature axis, ice is being separated from or informed us that the decay curve of the copper melted into a solution, as in the concentration or bombarded by fast neutrons from radon-beryllium dilution of a sugar solution. This latter effect may contained a period of a few hours which was absent also be brought about by capillary forces or by col when slow neutrons were used, or if the radioactive loidal substances the avidity of which for water copper was obtained from zinc by fast neutron varies with their concentration. bombardment. It was arranged with him that Fig. 3 shows the results obtained upon freezing further investigations and chemical separation should fresh green peas using time as a variable instead of be made in this laboratory. temperature. 19 gm. of green peas at room tempera We irradiated 2 gm. mols of pure cupric oxide with ture were placed in the condenser and immersed in a fast neutrons from a 200 me. radium-beryllium thermostat held at -16° C. At the time of immersion source. After irradiation, we dissolved the oxide, and at intervals thereafter capacitance measurements added 500 mgm. -
Impact-Ionization Mass Spectrometry of Cosmic Dust
IMPACT-IONIZATION MASS SPECTROMETRY OF COSMIC DUST Thesis by Daniel E. Austin Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy California Institute of Technology Pasadena, California 2003 (Defended November 5, 2002) ii © 2003 Daniel E. Austin All Rights Reserved iii Acknowledgements First of all, I thank Dave Dearden, Professor of Chemistry at Brigham Young University, and a former Caltech graduate student, for encouraging me to pursue graduate work at Caltech. The experiences I gained working with him, both as a research assistant and as a teaching assistant, proved invaluable during my stay here. Numerous people at Caltech have contributed in some way to my research efforts. Foremost among these is my advisor, Jack Beauchamp, who successfully balances providing advice and supervision with the hands-off approach that is essential to developing creativity, resourcefulness, and drive in students. I also thank all the other Beauchamp group members who have helped me in so many ways: Dmitri Kossakovski, Sang-Won Lee, Jim Smith, Heather Cox, Ron Grimm, Ryan Julian, and Rob Hodyss. I joined Jack’s group in part because of the very high caliber of students at that time. It seems I am leaving a group equally outstanding. There could be no finer collection of colleagues than this. Minta Akin, an undergraduate Caltech student, has helped tremendously with the ice accelerator, and I thank her for all her work. Mike Roy, Guy Duremberg, and Ray Garcia, the chemistry department machinists, have been both helpful and patient with me as I’ve built numerous instrument parts. -
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). -
Copper Isotope Fractionation During Surface Adsorption And
University of Texas at El Paso DigitalCommons@UTEP Open Access Theses & Dissertations 2010-01-01 Copper Isotope Fractionation During Surface Adsorption And Intracellular Incorporation By Bacteria Jesica Urbina Navarrete University of Texas at El Paso, [email protected] Follow this and additional works at: https://digitalcommons.utep.edu/open_etd Part of the Biogeochemistry Commons, Geochemistry Commons, and the Microbiology Commons Recommended Citation Navarrete, Jesica Urbina, "Copper Isotope Fractionation During Surface Adsorption And Intracellular Incorporation By Bacteria" (2010). Open Access Theses & Dissertations. 2553. https://digitalcommons.utep.edu/open_etd/2553 This is brought to you for free and open access by DigitalCommons@UTEP. It has been accepted for inclusion in Open Access Theses & Dissertations by an authorized administrator of DigitalCommons@UTEP. For more information, please contact [email protected]. COPPER ISOTOPE FRACTIONATION DURING SURFACE ADSORPTION AND INTRACELLULAR INCORPORATION BY BACTERIA JESICA URBINA NAVARRETE Environmental Science Program APPROVED: David Borrok, Ph.D., Chair Jasper G. Konter, Ph.D. Joanne T. Ellzey, Ph.D. Patricia D. Witherspoon, Ph.D. Dean of the Graduate School Copyright by Jesica Urbina Navarrete 2010 COPPER ISOTOPE FRACTIONATION DURING SURFACE ADSORPTION AND INTRACELLULAR INCORPORATION BY BACTERIA by JESICA URBINA NAVARRETE, B.S. THESIS Presented to the Faculty of the Graduate School of The University of Texas at El Paso in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE Department of Environmental Science THE UNIVERSITY OF TEXAS AT EL PASO August 2010 Acknowledgements This publication was made possible through funding by the National Science Foundation (NSF) grant 0745345, the Center for Earth and Environmental Isotope Research (NSF MRI grant 0820986) and by grant number 2G12RR008124-16A1 from the National Center for Research Resources (NCRR), a component of the National Institutes of Health (NIH). -
Cross Section Data for the Production of the Positron Emitting Niobium Isotope 90Nb Via the 90Zr(P, N)-Reaction
Radiochim. Acta 90, 1–5 (2002) by Oldenbourg Wissenschaftsverlag, München Cross section data for the production of the positron emitting niobium isotope 90Nb via the 90Zr(p, n)-reaction By S. Busse1,2,F.Rösch1,∗ andS.M.Qaim2 1 Institut für Kernchemie, Johannes Gutenberg-Universität, D-55128 Mainz, Germany 2 Institut für Nuklearchemie, Forschungszentrum Jülich GmbH, D-52425 Jülich, Germany (Received April 19, 2001; accepted in revised form July 16, 2001) Positron emitter 90Nb / Nuclear reaction / (α, 3n)-reactions on natural yttrium. A medium-sized cy- Excitation function / Calculated integral yield / clotron would allow the production of 90Nb via the (p, n)-, Experimental thick target yield / Radionuclidic impurities (d, 2n)- or the (3He, 2n)-process. In fact even a small-sized cyclotron (Ep ≤ 16 MeV) should lead to sufficient quanti- ties of the radioisotope via the (p, n)-reaction. A few stud- Summary. The radioisotope 90Nb decays with a positron ies have shown that the (d, 2n)-reaction requires a deuteron + branching of 53% and a relatively low β -energy of energy of about 16 MeV [5–7], the (3He, 2n)-process a 3He- = . = . Emean 0 66 MeV and Emax 1 5 MeV. Its half-life of 14 6h energy of ≥ 30 MeV and the (α, 3n)-reaction an α-particle makes it especially promising for quantitative investigation energy of ≥ 45 MeV [8]. Furthermore, the systematics of of biological processes with slow distribution kinetics using (3He, 2n)- and (p, n)-reactions suggest that the production positron emission tomography. To optimise its production, 90 the excitation functions of 90Zr(p, xn)-processes were studied yield of Nb should be higher in the latter process. -
Determining Atomic Mass Practice with Answers
Determining Atomic Mass Practice with Answers Atomic Mass • Refers to the mass of an atom. • Number of protons and neutrons • Atoms are too small to mass so mass is determined by the relative mass of a standard atom. By international agreement (IUPAC), Carbon12 is the chosen standard atom because of its abundance here on Earth. Atomic Mass Unit defined is a mass exactly equal to 1/12th of one carbon12 atom. 1 carbon12 atom = 12 amu Determining Atomic Mass Practice with Answers Determine Atomic Mass Unit for Hydrogen Hydrogen 1 as 1 proton and 0 neutrons 1/12 = .0833 x 100 = 8.33% So hydrogen is 8.33% of one atom of Carbon12 Atomic Mass of Hydrogen = mass of 1 atom of Carbon 12 x 8.33% = 12 x .0833 =.9996 = 1.0 amu Through different methods of experimental testing, chemists have more accurately determined the mass of hydrogen to be 1.008, which is more like 8.40%. Determining Atomic Mass Practice with Answers Determining Average Atomic Mass: Because element's usually have more than one isotope, which means their masses are different an average must be determine to reflect the mass of all an atom's isotopes. Example: A sample of cesium is 75% Cs-133, 20% Cs-132, and 5% Cs-134. What is the average atomic mass? ANSWER: .75 x 133 = 99.75 .20 x 132 = 26.4 .05 x 134 = 6.7 Total = 132.85 amu average atomic mass unit Determining Atomic Mass Practice with Answers Isotopes and Average Atomic Mass Iodine: 80% 127 I 17% 126 I 3% 128 I ANSWER: .80 x 127 = 101.6 .17 x 126 = 21.42 .03 x 128 = 3.84 Total = 126.86 amu Determining Atomic Mass Practice with Answers Determining Atomic Mass Practice with Answers Determining Atomic Mass Practice with Answers Determining Atomic Mass Practice with Answers Determining Atomic Mass Practice with Answers Determining Atomic Mass Practice with Answers Determining Atomic Mass Practice with Answers Determining Atomic Mass Practice with Answers Determining Atomic Mass Practice with Answers Determining Atomic Mass Practice with Answers Bromine which exists as a dark, red gas is Br2. -
Isotopic Composition of Some Metals in the Sun
SNSTITUTE OF THEORETICAL ASTROPHYSICS BLINDERN - OSLO REPORT .No. 35 ISOTOPIC COMPOSITION OF SOME METALS IN THE SUN by ØIVIND HAUGE y UNIVERSITETSFORLAqET • OSLO 1972 Universitetsfc lagets trykningssentral, Oslo INSTITUTE OF THEORETICAL ASTROPHYSICS BLINDERN - OSLO REPORT No. 35 ISOTOPIC COMPOSITION OF SOME METALS IN THE SUN by ØIVIND HAUGE UNIVERSITETSFORLAGET • OSLO 1972 Universitetsforlagets tryknlngssentral, Oslo CONTENTS Abstract 1 1. Introduction 2 2. Fine structure in spectral lines from atoms 5 1. Isotope shift 5 2. Hyperfine structure 6 3. Applications to atomic lines in photospheric spectrum .... 8 1. Elements with one odd isotope , 9 2. Elements with two odd isotopes 9 3. Elements with one odd and several even isotopes 11 k. Elements with several odd and even isotopes 11 h. Studies of elements in the Sun with two odd isotopes 1. Isotopes of rubidium 12 A. Observations lk B. Calculations 16 C. The Rb I line at 78OO Å 1. The continuum level 16 2. Line profiles and turbulent velocities 18 3. The asymmetry of the Si I line 19 h. Isotope investigations 21 P. The Rb I line at 79^7 A 28 E. The isotope ratio of rubidium 31 F. The abundance of rubidium 3k 2. Isotopes of antimony 35 A. Spectroscopic data 35 B. The Sb I lines at 3267 and 3722 A 37 3* Isotopes of europium 1*0 A. Observations and methods of analysis ^1 B. Spectroscopic data 1*1 C. Spectral line investigations 1. Investigations of four Eu II lines **3 2. The Eu II lines at Ul29 and U205 k ^6 D. The isotope ratio of europium 50 E. -
Isotopes of M&M-Ium
Name _________________________________________________________________ Hour __________________ Isotopes of m&m-ium Elements commonly exist with differing numbers of neutrons. We call these elements isotopes and an example is Bromine-79 and Bromine-81. These isotopes are naturally occurring…but do not exist equally in nature. Br-79 is more common and occurs 55% of the time while Br-81 occurs 45% of the time. To calculate the average atomic mass (the weighted average of the masses of its isotopes) of bromine you need to take into account the relative abundance of each element. The average atomic mass = (% abundance of isotope 1)x(mass of isotope 1) + (% abundance of isotope 2)x(mass of isotope 2) (% should be expressed in decimals) Pre-Lab Questions: 1. Calculate the average atomic mass of Bromine using the % abundances above: 2. Carbon has 2 stable isotopes: C-12 with a natural abundance of 98.89% and C-14 at 1.11%. Calculate the average atomic mass of Carbon. m&mium, a recently discovered element from the chocolate mountains of Wonkaland, exits as two isotopes. m&mium has many different colors and your job is to find the average atomic mass of one color of m&mium. Safety Precautions: Never eat anything that has touched lab equipment! Use a baking cup so your group can eat the m&ms when you are done! Procedure: Show all work for all calculations. 1. Record the number of small m&m’s and large m&m’s you have (your color only) in the table. 2. Record the total number of m&m’s you have.