chap14 - Chap 14 Energy Energy is the ability to do work. W...

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Chap 14 Energy Energy is the ability to do work. W = F x D US, 5% of population but use 25% of all energy generated. 1 st law of thermodynamics- energy is not created or destroyed. 2 nd Law of thermodynamics- energy does not flow spontaneousely from a cold to hot object.- Most of Earth’s energy comes from the fusion rxn inside the sun. We want useful energy types. High grade energy is degraded into low-grade forms. Mechanical energy heat energy cools off. Units of energy- calorie-heat 1 g of water 1 C. 1 cal = 4.184 J J= 1 jpule 1. Molecular level of chemical rxns energy progress of rxn reactants products H 2 + O 2 H 2 O 2H 2 O + energy O 2 + 2H 2 transition state energy of rxn transition energy
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C diamond + O 2 CO 2 a) Kinetics- how quickly a rxn takes place. 1. As temp rises, more collisions and more successful collisions. 2. Concentration of reactants. More molecules, more collisions. Ex. A spark in pure oxygen. 3. Catalyst or enzyme- lower activation energy and is not consumed in the rxn. b) Energy of rxn- endo exo rxns. 1. exothermic rxn- give off energy. energy of products is lower than the energy of reactants- CH 4 + 2O 2 CO 2 + H 2 O + 192 kcal 2. endothermic rxn- requires energy- products are higher in energy than reactants. 2H 2 O + 137 kcal 2H 2 + O 2 Ex. 1. Hails 2. photosynthesis 3. explosion of dynamite 4. metabolism Fuel Sources- 1. History- a) burning of wood. b) Egyptains used water power- 2000 years ago. 2. Fossil Fuels- 90% sustain our way life. Three major ones coal, petroleum, natural gas.
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Fossil fuels are being consumed rapidly, depletion occurs 50,000 times faster than being formed. In 1 century have used up more than 50% of fossil fuels. a) Coal- most abundant fossil fuel. US has 25% of the worlds supply. 52% of electricity comes from coal. 75,000 miners dig 1 billion tons of
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This note was uploaded on 09/02/2011 for the course CHEM 10 taught by Professor Harrison during the Spring '11 term at West Valley.

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chap14 - Chap 14 Energy Energy is the ability to do work. W...

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