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entropy - is a measure of disorder

entropy - is a measure of disorder. or the amount of chaos or randomness. disorder, being relative, needs a standard to measure against. so any substance at absolute zero (0 K) is given a value of 0 joule/mol . K. vaporization. gas. liquid. solid. entropy. melting. 0k. temperature.

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entropy - is a measure of disorder

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  1. entropy - is a measure of disorder or the amount of chaos or randomness disorder, being relative, needs a standard to measure against so any substance at absolute zero (0 K) is given a value of 0 joule/mol.K

  2. vaporization gas liquid solid entropy melting 0k temperature

  3. What is the entropy change for the vaporization of one mole of H2O?

  4. ? gas liquid solid entropy 0k temperature

  5. What is the entropy change for the vaporization of one mole of H2O? H2O(l)aH2O(g) Appendix C (Thermodynamic Quantities) has So values at 25oC DSo = SSo(products)- SSo(reactants)

  6. 69.96 188.7 J/mol.K H2O(l)aH2O(g) DSo = SSoH2O(g)- SSo H2O(l) DSo = 188.7 J/mol.K - 69.96 J/mol.K DSo = +118.74 J/mol.K a positive change in entropy means the system is becoming more disorderly (increasing in entropy)

  7. Some rxns you can just look at to see how entropy is changing….. N2(g) + 3 H2(g)a 2 NH3(g) 4 moles of gas a 2 moles of gas DSo is negative more orderly

  8. H2(10 atm)a H2(1 atm) more concentrated more spread out DSo is positive CuSO4(s)a CuSO4(aq) DSo is positive

  9. In general, entropy increases are expected to accompany processes in which: 1. Liquids or solutions are formed from solids. 2. Gases are formed from either solids or liquids 3. The number of molecules of gas increases during a chemical reaction. 4. The temperature of a substance is increased.

  10. Calculate DS for: N2(g) + 3 H2(g)a 2 NH3(g) 191.5 3(130.56) 2(192.5) DSo = SSo(products)- SSo(reactants) DS = 2(192.4) - [191.5 + 3(130.56)] = -198.2 J/K negative means there is a decrease in disorder

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