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Day 4 Chem 105 f2010

Day 4 Chem 105 f2010 - Chem Chem 105 105 Note some students...

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Unformatted text preview: Chem Chem 105 105 Note: some students still haven’t registered their clickers! See syllabus p 5. 1 GOT CLICKER (set to CC)? Learning Communities Li, Be, Al, Si please sit in rows 1&2 John D. Lamb, BYU Importantissimo large # of “drops” for Warm-up Friendly reminder: Quizzes, Practice Sheets, Micro-Exams “You can miss a few warm-up You designed to handle technical (mostly) quizzes without hurting your grade. Therefore, it is not and unavoidable personal problems necessary to provide make-up quizzes for times when you are NOT for avoidable reasons absent or have intermittent t difficulties entering Pleaseechnical You must attend the your request exceptions ONLY after answers. using minimum number of classes and up your drops—exceptional complete the warm-up quizzes to reasons required receive these points.” Syllabus Syllabus 2 John D. Lamb, BYU To add the class this week … Go to see the secretary in C100 BNSN, the main Chem office. 3 John D. Lamb, BYU Correct conversions can save lives! Boeing 767 ran out of fuel—nearly crashed. Why? Used wrong conversion factor to calculate fuel needed—lb/L vs. kg/L. 4 John D. Lamb, BYU Dry Run Micro-exam Do it before Learning Community tomorrow so if you have problems your PM can help. READ the Syllabus about micro-exams first! 5 John D. Lamb, BYU Objectives Objectives Understand scientists’ use of models, and specifically the model of light, to lay the foundation for understanding atoms atoms You’ve been introduced to the You’ve Bohr model in ChemTutor Bohr First: LIGHT! 1- Light as a wave: laser demo 6 John D. Lamb, BYU Taking notes Your notes serve as your review outline for exams. 7 John D. Lamb, BYU From Text reading: Choose the true statement: a) B has a greater amplitude and frequency than A b) B has a greater amplitude and wavelength than A c) B has a greater frequency and wavelength than A d) The national debt will be paid off in your lifetime. A B 8 John D. Lamb, BYU Properties of Waves Amplitude Wavelength Frequency – units Crest Trough Node Study the text! 9 John D. Lamb, BYU Standing Waves Push this 10 John D. Lamb, BYU Energy Energy What is the relative energy of UV light to that of visible red light? My portable phone boasts a frequency of 2.4 GHz. Energy? Use a different model! 11 John D. Lamb, BYU Which kind of light has the longest Which wavelength? wavelength? a) b) c) (g) 12 visible ultraviolet infrared flash- Memorize the order: Fig 6.4 Memorize John D. Lamb, BYU 2. Light as a particle: A particle of light is called a particle a) b) c) d) e) lighton beamium glowon photon brightium 13 John D. Lamb, BYU We say the energy of a light photon is a) b) c) d) quantized qualified quantitated quintessential 14 John D. Lamb, BYU Light as a “particle” (photon) not like a pebble packet of energy “quantized” photoelectric effect 15 John D. Lamb, BYU Participation: The energy of a Participation: photon of light is equal to photon a) b) c) d) hc hλ hν cλ 16 John D. Lamb, BYU 34 E = hν, where h ≈ 6.6 x 10--34 J-s where J-s Do the units work out? ν in Hz or s -1 17 John D. Lamb, BYU Light: Energy Light: Energy Joule: a little bit of energy About ¼ the energy needed to raise the temperature of 1 mL of water by 1 ºC. The amount of energy a 1-watt bulb gives off in 1 sec. 18 Light: our probe into the atom John D. Lamb, BYU 34 E = hν, where h ≈ 6.6 x 10--34 J-s where J-s c = λν Ergo, E = ? 19 equations, that is. John D. Lamb, BYU 20 John D. Lamb, BYU Models 21 John D. Lamb, BYU Models (class theme) Models (class A way of describing something we don’t understand in terms of more familiar things. platypus Like… Scientific simile or metaphor But IS it? Usually describes only part of whole reality 22 John D. Lamb, BYU Model of light Wave model (diffracts like waves—laser demo) Particle model (comes in packets—photoelectric effect) Free to use whichever is handy –why? Because neither is completely correct anyway! 23 “Wave-Particle Duality” John D. Lamb, BYU Light just can’t Light make up its mind. Wave-Particle Duality 24 John D. Lamb, BYU Level of Effort → The sad tale of A. Newman, The Chem 105 student: Chem 25 Easy—seen much of this before Behind—too late to catch up You You are here here Harder stuff, but now in relaxed mode Discourage ment Exam → Panic! Panic! Semester → Semester John D. Lamb, BYU Handy-dandy Handy-dandy Use proportionalities to describe relationships 26 John D. Lamb, BYU Proportionalities Proportionalities 27 α E = hν TW, mole, Important: IfBthismemorize theand Important: BTW,notis new like h but constants c = νλ but confusing Eto you, please read How does vary as ν? How does λ vary as ν? carefully my “Primer on How does E vary as λ? Express as ratios Proportionalities” on How would you show these Blackboardgraphically? relationships under “Readings/Helps.” “Readings/Helps.” John D. Lamb, BYU On the planet Gazebo, the laws of nature have been manipulated by a super race of munchkins to make calculations easier. On Gazebo, a photon of frequency 1000 Hz has an energy of 10 J. What is the energy of a photon of ν = 200 Hz? 28 John D. Lamb, BYU Back on earth, if the energy of a photon of Back ν = 1,000,000 s-1 is equal to 6.6 x 10-28 J, 6.6 12 what is the E of a photon of ν = 1012 Hz? a) b) c) d) 6.6 x 10-28 J 6.6 x 10-22 J 6.6 x 10-34 J none of these 29 John D. Lamb, BYU From ChemTutor According to the Bohr model of the According atom, the energies of the electrons around an atom around a) b) c) d) e) have positive values are quantized equal n, the orbit number are quantificated get further apart as n increases 30 John D. Lamb, BYU Objective Objective Relate atomic electron structure to the light emitted by glowing materials flame emissions— what’s going on? 31 John D. Lamb, BYU Questions about class details Look first to the syllabus Look second to your PM Look third to Dr. Lamb 32 John D. Lamb, BYU Arrivederci! Suggestion: Suggestion: Watch CT “Bohr Atomic Model” again! again! 33 John D. Lamb, BYU What is the mass in g of 1 billion tantalum What (Ta) atoms? (Atomic Weight = 181 g/mol) (Ta) a) 2 x 103 g b) 3 x 10-13 g c) 3 x 10-67 g 34 Same question for 1 million Ta+ ions… Why aren’t “a” and “c” viable answers? Let me show you this sample. John D. Lamb, BYU ...
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