CHAPTER 11 –Energy Levels
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Entropy: Ideal Gas Processes
Chapter 19: The Kinec Theory of Gases Thermodynamics = macroscopic picture Gases micro -> macro picture One mole is the number of atoms in 12 g sample Avogadro’s Number of carbon-12 23 -1 C(12)—6 protrons, 6 neutrons and 6 electrons NA=6.02 x 10 mol 12 atomic units of mass assuming mP=mn Another way to do this is to know the mass of one molecule: then So the number of moles n is given by M n=N/N sample A N = N A mmole−mass € Ideal Gas Law Ideal Gases, Ideal Gas Law It was found experimentally that if 1 mole of any gas is placed in containers that have the same volume V and are kept at the same temperature T, approximately all have the same pressure p. The small differences in pressure disappear if lower gas densities are used. Further experiments showed that all low-density gases obey the equation pV = nRT. Here R = 8.31 K/mol ⋅ K and is known as the "gas constant." The equation itself is known as the "ideal gas law." The constant R can be expressed -23 as R = kNA . Here k is called the Boltzmann constant and is equal to 1.38 × 10 J/K. N If we substitute R as well as n = in the ideal gas law we get the equivalent form: NA pV = NkT. Here N is the number of molecules in the gas. The behavior of all real gases approaches that of an ideal gas at low enough densities. Low densitiens m= enumberans tha oft t hemoles gas molecul es are fa Nr e=nough number apa ofr tparticles that the y do not interact with one another, but only with the walls of the gas container. -
On the Equation of State of an Ideal Monatomic Gas According to the Quantum-Theory, In: KNAW, Proceedings, 16 I, 1913, Amsterdam, 1913, Pp
Huygens Institute - Royal Netherlands Academy of Arts and Sciences (KNAW) Citation: W.H. Keesom, On the equation of state of an ideal monatomic gas according to the quantum-theory, in: KNAW, Proceedings, 16 I, 1913, Amsterdam, 1913, pp. 227-236 This PDF was made on 24 September 2010, from the 'Digital Library' of the Dutch History of Science Web Center (www.dwc.knaw.nl) > 'Digital Library > Proceedings of the Royal Netherlands Academy of Arts and Sciences (KNAW), http://www.digitallibrary.nl' - 1 - 227 high. We are uncertain as to the cause of this differencc: most probably it is due to an nncertainty in the temperature with the absolute manometer. It is of special interest to compare these observations with NERNST'S formula. Tbe fourth column of Table II contains the pressUl'es aceord ing to this formula, calc111ated witb the eonstants whieb FALCK 1) ha~ determined with the data at bis disposal. FALOK found the following expression 6000 1 0,009983 log P • - --. - + 1. 7 5 log T - T + 3,1700 4,571 T . 4,571 where p is the pressure in atmospheres. The correspondence will be se en to be satisfactory considering the degree of accuracy of the observations. 1t does riot look as if the constants could be materially improved. Physics. - "On the equation of state oj an ideal monatomic gflS accoJ'ding to tlw quantum-the01'Y." By Dr. W. H. KEEsmr. Supple ment N°. 30a to the Oommunications ft'om the PhysicaL Labora tory at Leiden. Oommunicated by Prof. H. KAl\IERLINGH ONNES. (Communicated in the meeting of May' 31, 1913). -
2. Molecular Stucture/Basic Spectroscopy the Electromagnetic Spectrum
2. Molecular stucture/Basic spectroscopy The electromagnetic spectrum Spectral region fooatocadr atomic and molecular spectroscopy E. Hecht (2nd Ed.) Optics, Addison-Wesley Publishing Company,1987 Per-Erik Bengtsson Spectral regions Mo lecu lar spec troscopy o ften dea ls w ith ra dia tion in the ultraviolet (UV), visible, and infrared (IR) spectltral reg ions. • The visible region is from 400 nm – 700 nm • The ultraviolet region is below 400 nm • The infrared region is above 700 nm. 400 nm 500 nm 600 nm 700 nm Spectroscopy: That part of science which uses emission and/or absorption of radiation to deduce atomic/molecular properties Per-Erik Bengtsson Some basics about spectroscopy E = Energy difference = c /c h = Planck's constant, 6.63 10-34 Js ergy nn = Frequency E hn = h/hc /l E = h = hc / c = Velocity of light, 3.0 108 m/s = Wavelength 0 Often the wave number, , is used to express energy. The unit is cm-1. = E / hc = 1/ Example The energy difference between two states in the OH-molecule is 35714 cm-1. Which wavelength is needed to excite the molecule? Answer = 1/ =35714 cm -1 = 1/ = 280 nm. Other ways of expressing this energy: E = hc/ = 656.5 10-19 J E / h = c/ = 9.7 1014 Hz Per-Erik Bengtsson Species in combustion Combustion involves a large number of species Atoms oxygen (O), hydrogen (H), etc. formed by dissociation at high temperatures Diatomic molecules nitrogen (N2), oxygen (O2) carbon monoxide (CO), hydrogen (H2) nitr icoxide (NO), hy droxy l (OH), CH, e tc. -
Ideal Gasses Is Known As the Ideal Gas Law
ESCI 341 – Atmospheric Thermodynamics Lesson 4 –Ideal Gases References: An Introduction to Atmospheric Thermodynamics, Tsonis Introduction to Theoretical Meteorology, Hess Physical Chemistry (4th edition), Levine Thermodynamics and an Introduction to Thermostatistics, Callen IDEAL GASES An ideal gas is a gas with the following properties: There are no intermolecular forces, except during collisions. All collisions are elastic. The individual gas molecules have no volume (they behave like point masses). The equation of state for ideal gasses is known as the ideal gas law. The ideal gas law was discovered empirically, but can also be derived theoretically. The form we are most familiar with, pV nRT . Ideal Gas Law (1) R has a value of 8.3145 J-mol1-K1, and n is the number of moles (not molecules). A true ideal gas would be monatomic, meaning each molecule is comprised of a single atom. Real gasses in the atmosphere, such as O2 and N2, are diatomic, and some gasses such as CO2 and O3 are triatomic. Real atmospheric gasses have rotational and vibrational kinetic energy, in addition to translational kinetic energy. Even though the gasses that make up the atmosphere aren’t monatomic, they still closely obey the ideal gas law at the pressures and temperatures encountered in the atmosphere, so we can still use the ideal gas law. FORM OF IDEAL GAS LAW MOST USED BY METEOROLOGISTS In meteorology we use a modified form of the ideal gas law. We first divide (1) by volume to get n p RT . V we then multiply the RHS top and bottom by the molecular weight of the gas, M, to get Mn R p T . -
Thermodynamics Molecular Model of a Gas Molar Heat Capacities
Thermodynamics Molecular Model of a Gas Molar Heat Capacities Lana Sheridan De Anza College May 7, 2020 Last time • heat capacities for monatomic ideal gases Overview • heat capacities for diatomic ideal gases • adiabatic processes Quick Recap For all ideal gases: 3 3 K = NK¯ = Nk T = nRT tot,trans trans 2 B 2 and ∆Eint = nCV ∆T For monatomic gases: 3 E = K = nRT int tot,trans 2 and so, 3 C = R V 2 and 5 C = R P 2 Reminder: Kinetic Energy and Internal Energy In a monatomic gas the three translational motions are the only degrees of freedom. We can choose 3 3 E = K = N k T = nRT int tot,trans 2 B 2 (This is the thermal energy, so the bond energy is zero { if we liquify the gas the bond energy becomes negative.) Equipartition Consequences in Diatomic Gases Reminder: Equipartition of energy theorem Each degree of freedom for each molecule contributes an and 1 additional 2 kB T of energy to the system. A monatomic gas has 3 degrees of freedom: it can have translational KE due to motion in 3 independent directions. A diatomic gas has more ways to move and store energy. It can: • translate • rotate • vibrate 21.3 The Equipartition of Energy 635 Equipartition21.3 The Equipartition Consequences of Energy in Diatomic Gases Predictions based on our model for molar specific heat agree quite well with the Contribution to internal energy: Translational motion of behavior of monatomic gases, but not with the behavior of complex gases (see Table the center of mass 21.2). -
Ijmp.Jor.Br V
INDEPENDENT JOURNAL OF MANAGEMENT & PRODUCTION (IJM&P) http://www.ijmp.jor.br v. 10, n. 8, Special Edition Seng 2019 ISSN: 2236-269X DOI: 10.14807/ijmp.v10i8.1046 A NEW HYPOTHESIS ABOUT THE NUCLEAR HYDROGEN STRUCTURE Relly Victoria Virgil Petrescu IFToMM, Romania E-mail: [email protected] Raffaella Aversa University of Naples, Italy E-mail: [email protected] Antonio Apicella University of Naples, Italy E-mail: [email protected] Taher M. Abu-Lebdeh North Carolina A and T State Univesity, United States E-mail: [email protected] Florian Ion Tiberiu Petrescu IFToMM, Romania E-mail: [email protected] Submission: 5/3/2019 Accept: 5/20/2019 ABSTRACT In other papers already presented on the structure and dimensions of elemental hydrogen, the elementary particle dynamics was taken into account in order to be able to determine the size of the hydrogen. This new work, one comes back with a new dynamic hypothesis designed to fundamentally change again the dynamic particle size due to the impulse influence of the particle. Until now it has been assumed that the impulse of an elementary particle is equal to the mass of the particle multiplied by its velocity, but in reality, the impulse definition is different, which is derived from the translational kinetic energy in a rapport of its velocity. This produces an additional condensation of matter in its elemental form. Keywords: Particle structure; Impulse; Condensed matter. [http://creativecommons.org/licenses/by/3.0/us/] Licensed under a Creative Commons Attribution 3.0 United States License 1749 INDEPENDENT JOURNAL OF MANAGEMENT & PRODUCTION (IJM&P) http://www.ijmp.jor.br v. -
Chemical Formulas the Elements
Chemical Formulas A chemical formula gives the numbers and types of atoms that are found in a substance. When the substance is a discrete molecule, then the chemical formula is also its molecular formula. Fe (iron) is a chemical formula Fe2O3 is a molecular formula The Elements The chemical formulas of most of the elements are simply their elemental symbol: Na (sodium) Fe (iron) He (helium) U (uranium) These chemical formulas are said to be monatomic—only an atom in chemical formula 1 The Elements There are seven elements that occur naturally as diatomic molecules—molecules that contain two atoms: H2 (hydrogen) N2 (nitrogen) O2 (oxygen) F2 (fluorine) Cl2 (chlorine) Br2 (bromine) I2 (iodine) The last four elements in this list are in the same family of the Periodic Table Binary Compounds A binary compound is one composed of only two different types of atoms. Rules for binary compound formulas 1. Element to left in Periodic Table comes first except for hydrogen: KCl PCl3 Al2S3 Fe3O4 2 Binary Compounds 2. Hydrogen comes last unless other element is from group 16 or 17: LiH, NH3, B2H4, CH4 3. If both elements are from the same group, the lower element comes first: SiC, BrF3 Other Compounds For compounds with three or more elements that are not ionic, if it contains carbon, this comes first followed by hydrogen. Other elements are then listed in alphabetical order: C2H6O C4H9BrO CH3Cl C8H10N4O2 3 Other Compounds However, the preceding rule is often ignored when writing organic formulas (molecules containing carbon, hydrogen, and maybe other elements) in order to give a better idea of how the atoms are connected: C2H6O is the molecular formula for ethanol, but nobody ever writes it this way—instead the formula is written C2H5OH to indicate one H atom is connected to the O atom. -
Syllabus of Biochemistry (Hons.)
Syllabus of Biochemistry (Hons.) for SEM-I & SEM-II under CBCS (to be effective from Academic Year: 2017-18) The University of Burdwan Burdwan, West Bengal 1 1. Introduction The syllabus for Biochemistry at undergraduate level using the Choice Based Credit system has been framed in compliance with model syllabus given by UGC. The main objective of framing this new syllabus is to give the students a holistic understanding of the subject giving substantial weight age to both the core content and techniques used in Biochemistry. The ultimate goal of the syllabus is that the students at the end are able to secure a job. Keeping in mind and in tune with the changing nature of the subject, adequate emphasis has been given on new techniques of mapping and understanding of the subject. The syllabus has also been framed in such a way that the basic skills of subject are taught to the students, and everyone might not need to go for higher studies and the scope of securing a job after graduation will increase. It is essential that Biochemistry students select their general electives courses from Chemistry, Physics, Mathematics and/or any branch of Life Sciences disciplines. While the syllabus is in compliance with UGC model curriculum, it is necessary that Biochemistry students should learn “Basic Microbiology” as one of the core courses rather than as elective while. Course on “Concept of Genetics” has been moved to electives. Also, it is recommended that two elective courses namely Nutritional Biochemistry and Advanced Biochemistry may be made compulsory. 2 Type of Courses Number of Courses Course type Description B. -
GANPAT UNIVERSITY FACULTY of SCIENCE TEACHING and EXAMINATION SCHEME Programme Bachelor of Science Branch/Spec
GANPAT UNIVERSITY FACULTY OF SCIENCE TEACHING AND EXAMINATION SCHEME Programme Bachelor of Science Branch/Spec. Microbiology Semester I Effective from Academic Year 2015- Effective for the batch Admitted in June 2015 16 Teaching scheme Examination scheme (Marks) Subject Subject Name Credit Hours (per week) Theory Practical Code Lecture(DT) Practical(Lab.) Lecture(DT) Practical(Lab.) CE SEE Total CE SEE Total L TU Total P TW Total L TU Total P TW Total UMBA101FOM FUNDAMENTALS 04 - 04 - - - 04 - 04 - - - 40 60 100 - - - OF MICROBIOLOGY UCHA101GCH GENERAL 04 - 04 - - - 04 - 04 - - - 40 60 100 - - - CHEMISTRY-I UPHA101GPH GENERAL 04 - 04 - - - 04 - 04 - - - 40 60 100 - - - PHYSICS-I UENA101ENG ENGLISH-I 02 - 02 - - - 02 - 02 - - - 40 60 100 - - - OPEN SUBJECT – 1 02 - 02 - - - 02 - 02 - - - 40 60 100 - - - UPMA101PRA PRACTICAL - - - 02 - 02 - - - 04 - 04 - - - - 50 50 MODULE-I UPCA101PRA PRACTICAL - - - 02 - 02 - - - 04 - 04 - - - - 50 50 MODULE-I UPPA101PRA PRACTICAL - - - 02 - 02 - - - 04 - 04 - - - - 50 50 MODULE-I Total 16 - 16 06 - 06 16 - 16 12 - 12 200 300 500 - 150 150 GANPAT UNIVERSITY FACULTY OF SCIENCE Programme Bachelor of Science Branch/Spec. Microbiology Semester I Version 1.0.1.0 Effective from Academic Year 2015-16 Effective for the batch Admitted in July 2015 Subject code UMBA 101 Subject Name FUNDAMENTALS OF MICROBIOLOGY FOM Teaching scheme Examination scheme (Marks) (Per week) Lecture(DT) Practical(Lab.) Total CE SEE Total L TU P TW Credit 04 -- -- -- 04 Theory 40 60 100 Hours 04 -- -- -- 04 Practical -- -- -- Pre-requisites: Students should have basic knowledge of Microorganisms and microscopy of 10+2 level. Learning Outcome: The course will help the student to understand basic fundamentals of Microbiology and history of Microbiology. -
Chemistry in One Dimension Pierre-Fran¸Coisloos,1, A) Caleb J
Chemistry in One Dimension Pierre-Fran¸coisLoos,1, a) Caleb J. Ball,1 and Peter M. W. Gill1, b) Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia We report benchmark results for one-dimensional (1D) atomic and molecular sys- tems interacting via the Coulomb operator jxj−1. Using various wavefunction-type approaches, such as Hartree-Fock theory, second- and third-order Møller-Plesset per- turbation theory and explicitly correlated calculations, we study the ground state of atoms with up to ten electrons as well as small diatomic and triatomic molecules containing up to two electrons. A detailed analysis of the 1D helium-like ions is given and the expression of the high-density correlation energy is reported. We report the total energies, ionization energies, electron affinities and other interesting properties of the many-electron 1D atoms and, based on these results, we construct the 1D analog of Mendeleev's periodic table. We find that the 1D periodic table contains only two groups: the alkali metals and the noble gases. We also calculate the dissociation + 2+ 3+ curves of various 1D diatomics and study the chemical bond in H2 , HeH , He2 , + 2+ H2, HeH and He2 . We find that, unlike their 3D counterparts, 1D molecules are + primarily bound by one-electron bonds. Finally, we study the chemistry of H3 and we discuss the stability of the 1D polymer resulting from an infinite chain of hydrogen atoms. PACS numbers: 31.15.A-, 31.15.V-, 31.15.xt Keywords: one-dimensional atom; one-dimensional molecule; one-dimensional polymer; helium-like ions arXiv:1406.1343v1 [physics.chem-ph] 5 Jun 2014 a)Electronic mail: Corresponding author: [email protected] b)Electronic mail: [email protected] 1 I. -
Laser Cooling and Slowing of a Diatomic Molecule John F
Abstract Laser cooling and slowing of a diatomic molecule John F. Barry 2013 Laser cooling and trapping are central to modern atomic physics. It has been roughly three decades since laser cooling techniques produced ultracold atoms, leading to rapid advances in a vast array of fields and a number of Nobel prizes. Prior to the work presented in this thesis, laser cooling had not yet been extended to molecules because of their complex internal structure. However, this complex- ity makes molecules potentially useful for a wide range of applications. The first direct laser cooling of a molecule and further results we present here provide a new route to ultracold temperatures for molecules. In particular, these methods bridge the gap between ultracold temperatures and the approximately 1 kelvin temperatures attainable with directly cooled molecules (e.g. with cryogenic buffer gas cooling or decelerated supersonic beams). Using the carefully chosen molecule strontium monofluoride (SrF), decays to unwanted vibrational states are suppressed. Driving a transition with rotational quantum number R=1 to an excited state with R0=0 eliminates decays to unwanted ro- tational states. The dark ground-state Zeeman sublevels present in this specific scheme are remixed via a static magnetic field. Using three lasers for this scheme, a given molecule should undergo an average of approximately 100; 000 photon absorption/emission cycles before being lost via un- wanted decays. This number of cycles should be sufficient to load a magneto-optical trap (MOT) of molecules. In this thesis, we demonstrate transverse cooling of an SrF beam, in both Doppler and a Sisyphus-type cooling regimes. -
Chapter 10 100 Years of Progress in Gas-Phase Atmospheric Chemistry Research
CHAPTER 10 WALLINGTON ET AL. 10.1 Chapter 10 100 Years of Progress in Gas-Phase Atmospheric Chemistry Research T. J. WALLINGTON Research and Advanced Engineering, Ford Motor Company, Dearborn, Michigan J. H. SEINFELD California Institute of Technology, Pasadena, California J. R. BARKER Climate and Space Sciences and Engineering, University of Michigan, Ann Arbor, Michigan ABSTRACT Remarkable progress has occurred over the last 100 years in our understanding of atmospheric chemical composition, stratospheric and tropospheric chemistry, urban air pollution, acid rain, and the formation of airborne particles from gas-phase chemistry. Much of this progress was associated with the developing un- derstanding of the formation and role of ozone and of the oxides of nitrogen, NO and NO2, in the stratosphere and troposphere. The chemistry of the stratosphere, emerging from the pioneering work of Chapman in 1931, was followed by the discovery of catalytic ozone cycles, ozone destruction by chlorofluorocarbons, and the polar ozone holes, work honored by the 1995 Nobel Prize in Chemistry awarded to Crutzen, Rowland, and Molina. Foundations for the modern understanding of tropospheric chemistry were laid in the 1950s and 1960s, stimulated by the eye-stinging smog in Los Angeles. The importance of the hydroxyl (OH) radical and its relationship to the oxides of nitrogen (NO and NO2) emerged. The chemical processes leading to acid rain were elucidated. The atmosphere contains an immense number of gas-phase organic compounds, a result of emissions from plants and animals, natural and anthropogenic combustion processes, emissions from oceans, and from the atmospheric oxidation of organics emitted into the atmosphere.