CHEM 1211 Lecture 14Outline of Last Lecture I. Table OneII. EnthalpyIII. CalorimetryIV. Hess’s LawOutline of Current Lecture I. Hess’s law continuedII. Chapter 6: Atoms Electronic StructureIII. Color in Neon Lights, Fireworks, etc…A. Properties of Light (photon)IV. Constant Frequency & Variable WavelengthA. Photoelectric EffectB. Light & EnergyCurrent Lecture: I. Hess’s law continued H°f1N2(g) + ½O2(G) 1N2O(g)1Na(s) + ½Cl2(g) 1NaCl(s)- Use standard statesEXOTHERMIC!H°rxn= Σn H°f products - Σn H°f reactants- Trying to get to low energy state1. H°C3H8= -104.7 KJ/molH°CO2= -393.5 KJ/molH°O2= 0.0 KJ/molH°H2O= -285.8 KJ/molCalculate the H°298 for this reaction:C3H8 (g) + 5O2 (g) 3CO2 (g) + 4H2O (l)H°rxn: [(3)(-393.5) + (4)(-285.8)] – [(1)(-104.7)]H°rxn: -2,219 KJ/mol : EXOTHERMIC.II. Chapter 6: Atoms Electronic StructureIII. Color in Neon Lights, Fireworks, etc…Use: Barium, Copper, Strontium… molecular compounds (lightning bugs)A. Properties of Light (photon)- Osolating electric field - Wavelength: m, cm, nm, A- A = 1 x 10-10m or 1 x 10-8cm- Period: unit is seconds- Frequency: V = 1/PV= Frequency of Hertz (Hz)P= Period- Velocity: v= uƛƛ = wavelengthU= frequency in HzV= velocity in m/s or cm/sEX: VACUUM: 3.0 x 108 m/s or 3.0 x 1010 cm/sIV. Constant Frequency & Variable Wavelength- Frequency of photon is constantA. Photoelectric Effect: lights can strike the surface of some metals causing an e- to be ejected.Work fxn = Ф = hvo WAVE PARTICLE DUALITYB. Light & Energy: 1900 Max Planck (black body radiation)1. Energy is quantized2. Light has particle characterE = hv or E = hc / ƛ or E = nhvH= 6.626 x 10-34 J x SEphoton = Ʋ or
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