Chem 1061 1st Edition Lecture 17 Outline of Last Lecture 1. Hess’s Law: Adding Reactions and Enthalpies2. Standard Enthalpies of a Reactiona. Standard Conditionb. Heat of FormationOutline of Current Lecture 3. Definitionsa. Heat of Formationb. Heat of Combustionc. Heat of Vaporizationd. Heat of Fusion4. Determining Heat of Reactions from Heat of Formation5. Quantum Theory and Atomic Structurea. Definitions6. Electromagnetic RadiationCurrent LectureDefinitionsHeat of Formation: Reaction of elements to form 1mol of a compoundCa(s) + C(s) + 3/2O2(g) CaCO3(s) ∆HºfHeat of Combustion: How much energy per mol fuel reactantCH4(g) + 2O2(g) CO2(g) + 2H2O(g) ∆H(combustion)Heat of Vaporization: Liquid to gas reactionsH2O(l) H2O(g) ∆H(vap) = + (Takes energy = endothermic)H2O(g) H2O(l) ∆H(vap) = - (absorbs energy = exothermic)Heat of Fusion: Solid to a liquidH2O(s) H2O(l) ∆H(fusion)= +H2O(l) H2O(s) ∆H = -These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Determining Heat of Reactions from Heat of FormationNH3(g) + HCL(g) NH4Cl(s) ∆H=?1) 1/2 N2(g) + 3/2H2(g) NH3(g) ∆Hºf = -45.9kJ/mol2) ½ H2(g) + ½ Cl2(g) HCl(g) ∆Hºf= -92.3kJ/mol3) ½ N2(g) + 2H2(g) + 1/2Cl2(g) NH4Cl(s) ∆Hºf= -314.4 kJ/mol∆Hºrxn = Σm x ∆Hºf(products) – Σn x ∆Hºf(reactants)∆Hºrxn= [(1mol NH4Cl)(∆Hºf NH4Cl)] – [(1mol NH3)(∆Hºf NH3) + (1mol HCl)(∆Hºf HCl)]∆Hºrxn= [(1mol)(-314.4kJ/mol)] – [(1mol)(-45.9kJ/mol) + (1mol)(-92.3kJ/mol)]∆Hºrxn = -176.2 kJUse ∆Hºf values to calculate ∆Hºrxn for:4Al(s) + 3MnO2(s) 2Al2O3(s) + 3Mn(s)∆Hºf kJ/mol:Al = 0MnO2 = -520.9Al2O3 = -1676Mn = 0[(2mol)(-1676)] – [(3mol)(-520.9)] = -1789.3 kJQuantum Theory and Atomic StructureQuantum Mechanics: the theory that explain fundamental nature of energy and matter and accounts for atomic structure.Light (classical): wave propertiesMatter (classical): particle natureQuantum: particle properties of light and wave properties of matterElectromagnetic Radiation: (Figure 7.3) Describes wave with frequency and wavelengthC(speed of light) = wavelength x
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