Chem 101 1nd EditionExam # 3 Study Guide Lectures: 14-21½ m(kg)(v^2)Evolved= exothermic so q= negative whatever kJ equalsAbsorbed= endothermic so q= whatever kJ equalsSpecific Heat = q/m T = j/g °C Δq= joules, m= mass in grams, T is change in temperatureΔJoules (q)= m T(Specific Heat)Δ2.9 =48.4/(t2-20.3)Heat needed to vaporize sample = (Grams of sample x molar mass of sample) x HΔ vapFreezing= grams to molar mass of sample x (- HΔ fus)Melting = grams to molar mass of sample x ( HΔ fus)The specific heat is used to calculate energy changes when the temperature of a single state is changing:A-B: for the solid- the specific heat of the solidD-F: for the liquid- the specific heat of the liquidH-J: for the gas- the specific heat of the gasFor a phase change at constant temperatureB-D: solid to liquid- the heat of fusionF-H: liquid to gas- the heat of vaporizationThe removal of heat will cause some of the sample to condense at points G and HConversion from one state to another occurs when energy is added or removed on the horizontal line segments. Two states are present Between points B-D: solid and liquid at the melting point temperatureBetween points F-H: liquid and gas at the boiling point temperatureWhere the temperature is changing, only one state is present:Between points A-B: solidBetween points D-F: liquidBetween the points H-J: gas1. Heat the solid: q= m x Csp x TΔ2. Melt the solid: q= m x HΔ fus3. Heat the liquid: q= m x Csp x TΔΔE = ΔU = q + wΔE = change in the internal energy of the systemq = energy exchanged between the system and the surroundings as heatw = energy exchanged between the system and the surroundings as workIf q>0 then the system absorbs heat; left side of the equationIf q<0 then the system evolves heat; right side of the equationIf w>0 then the surroundings does work on the systemIf w<0 then the system does work on the surroundingskJ given x kJ/mole x molar massgrams of compound x molar mass x kJ per compoundEnthalpy of dissolution = (total mass x C water x ΔT) + (C calorimeter x ΔT) mass of compoundAnswer x molar mass of compound /1000 = final answerEnergy released during combustion = mass of sample x molar mass x kcal/molIf you reverse a reaction, then the ΔH reverses as wellFrequency and Energy (Lowest to Highest)Red Orange Yellow Green Blue Indigo VioletRadio Wave Microwave Infrared Visible ^ UV X-Ray Gamma rayWavelength (Lowest to Highest)Violet Indigo Blue Green Yellow Orange Red Gamma ray X-Ray UV Visible ^ Infrared Microwave Radio waveHigh wavelength = shorter line on graphHigh frequency/energy = longer line on graphAbsorption of energy = upward line on graphEmission of energy = downward line on graphv=cλWhere c =3.00E+8E= hv= hc/λWhere h = 6.626E-34 ΔE in J= -2.179E-18/n^2 = c/mvλAtomic radii increases from right to left and from the top to the bottom of the periodic table. Ionization energy is the
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