ENERGYEnergyPowerPower is energy over timeTypes of EnergyMechanical EnergyPotential EnergyKinetic EnergyEnergyEnergy conversionEnergy conversionEnergy conversionSteam TurbineEarth’s EnergySun’s EnergyPhotosynthesisSource of energy not from SunBlack SmokerVent communityTube worm and crabEnergy and Chemical ReactionsEnergy and Chemical ReactionsReaction energyExothermic ReactionEndothermic reactionConservation of EnergyHeat FlowEntropyEnergy sourcesFossil fuelsFossil fuelsFirst law of thermodynamicsFossil fuelsCoalCoalCarboniferous Period ForestCoal formation 1Coal formation 2Coal formation 3Coal formation 4Coal formation SummaryCoalCoalNatural GasPetroleumPetroleumENERGYReading:Supplemental Text MaterialsChapter 11: pages 225-238Energy• Ability to do work• Unit: “Joule” (J)•J = (kg x m2)/s2Power• Energy over time• Watts (W)• 1 W = 1J/sPower is energy over timehttp://www.dodgeglobe.com/images/102901/hiker.jpgTypes of Energy• Mechanical • Electrical• Chemical• Radiant (Light)• Heat• NuclearMechanical Energy• Potential Energy• Kinetic EnergyPotential EnergyStored energyKinetic EnergyEnergy of motionEnergy• Conversion • From high-grade to lower-grade formsEnergy conversion• Mechanical to ElectricalEnergy conversion• Chemical to mechanicalEnergy conversion• Radiant to heat• Radiant to electricalSteam Turbinehttp://www.uaf.edu/energyin/webpage/pages/heat_engines/steam_and_gas_turbines.htmEarth’s Energy• Sun—99+% of Earth’s energy• Internal heat– radioactive decay– gravitational pressureSun’s Energy• Radiant energy – Released by fusion– Hydrogen fused into Helium• 1.73 x 1017watts received by Earth from Sun• Converted by plants into chemical energyPhotosynthesis6 CO2+ 6 H2O Æsun energy Æ C6H12O6+ O2–Converts CO2and H2O to sugar and O2– Created the level of oxygen present in today’s atmosphere– Ancient algae in Archean and Proterozoic oceans released O2by photosynthesisSource of energy not from Sun• Rare deep sea vent communities• Sulfurous hotsprings supports bacteria• Other organisms subsist on bacteria• Larger creatures can survive on the bacteria-eating organismsBlack Smokerhttp://www.punaridge.org/doc/factoids/Biology/Vent communityhttp://www.punaridge.org/doc/factoids/Biology/Tube worm and crabhttp://www.punaridge.org/doc/factoids/Biology/Energy and Chemical Reactions• Temperature affects rate of reactions– More molecule collisions– More energy to break chemical bonds• Concentration of reactants• Presence of catalyst– Peroxide 2 H2O2Æ 2 H2O + O2proceeds slowly– Add platinum: takes seconds, not yearsEnergy and Chemical Reactions• Heat released or consumed in chemical reactions• Measured in calories– Food ‘calorie’ is a kilocalorie (kcal)– 1 Joule = 0.24 calories• Energy shown in equation•C3H8+ 5 O2Æ 3 CO2+ 4 H2O + 526 kcalReaction energyEXOTHERMICheats up environmentENDOTHERMICabsorbs heat from environmentExothermic ReactionC3H8+ 5 O2Æ 3 CO2+ 4 H2O + 526 kcal• Burn 2 moles of propane• 2 x 526 kcal = 1052 kcal• Burn 308 g of propane• 308 g (1 mole/44g) = 7 moles• 7 moles x 526 kcal = 3682 kcalEndothermic reactionN2+ O2+ 4.32 kcal Æ 2 NO• 5 moles of nitrogen, reacting with 5 moles of oxygen• Consumes 5 x 4.32 kcal = 21.6 kcalConservation of Energy• Energy is not created or destroyed• First Law of ThermodynamicsHeat Flow• From objects with heat to those with less• Change form from high quality to lower quality– Chemical to heat–frictionEntropy• Lack of order of systems• Nature tends toward disorder—greater entropy• Takes energy to overcome entropy– Oil spill on Columbia River– CFC released into atmosphereEnergy sources• Wood—chemical energy stored by plants• Kinetic energy—– Water power to grind grain– Wind to pump water• Fossil fuelsFossil fuels• Burn readily• Reaction is oxidation• Release heat energyFossil fuels• Coal• Petroleum• Natural GasFirst law of thermodynamics• Conservation of energy• Cannot create or destroy energy• (But we can convert to less-useful form)Fossil fuels• Non renewable• From ancient organisms• Extracted from EarthCoalC + O2Æ CO2• Anthracite• Bitumen • LigniteCoal• Incompletely decayed plants• Burial pressure releases O2 and H2• Carbon remains• Paleozoic—Pennsylvanian coal, Carboniferous EraCarboniferous Period Foresthttp://palaeos.com/Paleozoic/Carboniferous/Carboniferous.htmCoal formation 1Coal formation 2Coal formation 3Coal formation 4Coal formation SummaryCoal• Must be mined• Pollutants in coal– Sulfur leads to acid rain– Also contains mercury, arsenic, nitratesCoal• ‘Coke’ is made by heating coal • Byproduct refined into organic chemicalsNatural Gas• Mostly methaneCH4+ 2 O2Æ CO2 + 2 H2O + heat• Excellent, clean-burning fuel• Raw material for plastics and other chemicalsPetroleum• Replaced coal by about 1950• Complex hydrocarbon molecules • Derived from fats• Combustion products are carbon dioxide and waterPetroleumC8H18+ 18 O2Æ 16 CO2+ 18 H2O• Also contains some sulfur compounds• Fuel oil is fairly clean• Burning gasoline results in smog– Internal combustion engines
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