chapter 8 lecture notes

High potential low potential kinetic thermodynamics

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Unformatted text preview: --------oca,on or arrangement Example: Chemical energy is the potential energy available for release in chemical reactions How would you classify the energy of these three pictures? high potential low potential kinetic Thermodynamics: The study of energy transforma,on In open systems, energy and maRer can be exchanged between the system and the surroundings Adds disorder to the surroundings Chemical Energy Kine,c Energy First Law: Energy can be transferred or transformed, but it cannot be created or destroyed Example: Chemical reac,ons in the cheetah will convert the chemical (poten,al) energy in food to the kine,c energy of the cheetah’s movement Second Law: Every energy transfer or transformaAon increases the disorder (entropy) of the universe Example: As the cheetah runs, disorder is increased around the cheetah by the release of heat and the small molecules that are the result of cellular respira,on * for a process to occur in an energetically favorable manner (eg. spontaneously), it must increase the entropy or the universe Free Energy Change (G): A livings system’s free energy is the energy that can do work under cellular condi,ons Δ = Change ΔG = ΔH – TΔS ΔH = Change in Enthalpy (total energy) T = Absolute Temperature in Kelvin (K = °C +273) ΔS = Change in Entropy Spontaneous processes: have a -delta G (less than zero) Can think of free energy as a measure of a systems instability ----------- ΔG = G final – G iniIal H+ Diffusion Glucose High Free energy (G) Less Stable Great Work Capacity  ­ΔG Chemical Reac,ons CO2, H2O Less free energy more stable less work capacity Once at equilibrium, a system is at a minimum of free energy and it will not change spontaneously Free Energy, Stability, and Equilibrium ΔG = G final – G iniIal Can think of G as a measure of a systems instability System with high Free Energy (G) System with low Free Energy (G) Stability Low High Spontaneous Will change spontaneously Equilibrium Not at equilibrium Work Capacity High will not change spontaneously already at equilibrium Low Exergonic Reac1ons in Metabolism ( ­ΔG): Spontaneous Maximum amount of work the reac,on can do C6H1206 + 6O2 6CO2 + 6H20 ΔG =  ­686 kcal/mo...
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This document was uploaded on 02/10/2014.

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