Born-Oppenheimer approximation. Along with nuclear dynamics problem‚ electronic structure problem is one of the two steps to study quantum mechanical motion of a molecular system. Except for a small number of simple problems such as hydrogen-like atoms‚ the solution of electronic structure problems require modern computers. Electronic structure problem is routinely solved with quantum chemistry computer programs. Electronic structure calculations rank among the most computationally intensive tasks
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Chapter 5: Solutions‚ Colloids‚ and Membranes Chapter Summary Mixtures and Solutions * A mixture maintains its identity regardless of the proportions of its components. * A mixture can be separated into its pure components through physical separation techniques. * The components are distributed uniformly throughout a homogenous mixture. * The components are not distributed uniformly throughout a heterogeneous mixture. * A solution is composed of a solvent and one or more solutes
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Christopher Torres Environmental Studies Notes Chapter 1 Understanding Our Environment Atmosphere: Air Hydrosphere: Water (Ice-Cryosphere) Geosphere: Land Biosphere: Everywhere you find living thing Science: ”To know” A way of knowing following scientific methods that gives you higher chance of objective and accurate answers Basic Principles of Science Empiricism: Science is evidence based Uncertainty/Proof is elusive: Science can’t prove anything Can support hypothesis Scientific
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Chemistry Revision F331 Isotopes - atoms with the same atomic number‚ but different mass numbers 131I - radioactive tracer for thyroid. 99Tc for tumours. Radioisotopes - gamma emitters & short half life - long enough to detect‚ but not long enough for damage. Beta particles emitters are more useful than alpha particle emitters because they penetrate more and so are more easily detected. Also‚ less damaging. The half life is the time taken for half the isotope to decay Mass left = initial
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What is a Functional Group? A functional group is a portion of a molecule that is a recognizable/classified group of bound atoms. In organic chemistry it is very common to see molecules comprised mainly of a carbon backbone with functional groups attached to the chain. The functional group gives the molecule its properties‚ regardless of what molecule contains it*; they are centers of chemical reactivity. The functional groups within a molecule need to be identified when naming. *Definition taken
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6753_Klein_00.qxd 5/1/07 5:02 PM Page ii 6753_Klein_00.qxd 5/1/07 5:02 PM Page i 6753_Klein_00.qxd 5/1/07 5:02 PM Page ii 6753_Klein_00.qxd 5/15/07 2:14 PM Page iii ORGANIC CHEMISTRY I AS A SECOND LANGUAGE Second Edition DR. DAVID R. KLEIN Johns Hopkins University JOHN WILEY & SONS‚ INC. 6753_Klein_00.qxd 5/1/07 Marketing Manager Production Manager Production Editor Cover Designer 5:02 PM Page iv Amanda Wygal Pamela
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than the speed of sound. This produces a shock wave‚ a sonic boom. The colors are produced by heating metal salts‚ such as calcium chloride or sodium nitrate‚ that emit characteristic colors. The atoms of each element absorb energy and release it as light of specific colors. The energy absorbed by an atom rearranges its electrons from their lowest-energy state‚ called the ground state‚ up to a higher-energy state‚ called an excited state. The excess energy of the excited state is emitted as light
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“REDEFINITION OF THE KILOGRAM TABLE OF CONTENT Contents 1.0 LITERATURE REVIEW It is only the Kilogram in the International System (SI) that is defined by a monument: the International kilogram prototype (IPK). The feasible changes in International prototype Kilogram (IPK) may result in imbalances in international system (SI) unit as some other units in the SI depend on the kilogram for their definition and
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HOMEWORK EXAM 3: Chapter 19: The half life of 90Sr is 29 years. What fraction of the atoms in a sample of 90Sr would remain 175 years later? Answer 0.166 0.125 0.062 here 0.015 Which relation is not correct? Answer 11p = 11H = proton 0-1e = 0-1β = electron here +10e = +10β= positron 10n = neutron As a result of beta decay‚ the product nucleus is Answer one atomic number lower than the original element. two atomic number
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cathode rays carry negative charge and identified the cathode rays inside vacuum tubes as being electric currents composed of these tiny electrons (Hamblin‚ 2005). It was the crucial first step in the development of the twentieth-century concept of the atom (Simmons‚ 1996). In the following paragraphs‚ I will introduce the Thomson’s life and his important achievements. Biographical information J.J. Thomson was born at Cheetham Hill‚ a suburb of Manchester‚ England on December 18‚ 1856. His father
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