CHEM 104 1st Edition Lecture 25 Matter and energy will disperse in a spontaneous process entropy o Ex probability that 2 particles stay in initial flask 1 2 2 Probability that 3 particles stay in initial flask 1 2 3 1 8 Probability that all particles will stay in initial flask 1 2 N 0 N 6 022 1023 particles i e 1 mol There is much higher probability that energy is dispersed over many particles than concentrated in only a few particles Entropy measure of how many microstates are associated with a particular macroscopic state o Entropy is state function i e S Sfinal Sinitial S klnW o S entropy k Boltzmann constant 1 38 10 23 J k W number of microstates o S kln Wf Wi o S qreverse T If Wfinal Winital S 0 signifies dispersion of matter energy more microstates q heat transferred reversibly into the system T temperature in Kelvin Second law of thermodynamics the entropy of the universe increases in a spontaneous process o Suniverse Ssystem Ssurroundings 0 Entropy and physical states S s S l S g Entropy and solutions when a solid is dissolved in a solvent entropy increases same for liquids gases in solutions i e mixtures Entropy and chemical reactions depends on states and the greater the number of moles the higher the entropy Third law of thermodynamics the entropy of a crystalline solid is zero at 0 Kelvin o S klnW if W 1 then S O Larger and more complex molecules have greater entropies 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 Standard molar entropies S molar entropies for substances at standard conditions i e 1 bar 298 K o S increase for solid liquid gas o S for elements 0 o Larger molecules have higher S S nproductsS products nreactantsS reactants
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