Ch. 20: Entropy and Free Energy. Thermodynamics: the science of energy transfer Objective: To learn how chemists predict when reactions will be product-favored vs. when they will be reactant-favored . Section 20.1. Ø Thermodynamics tells us NOTHING about the rate of reaction.
ØEntropy usually increases when a pure liquid or solid dissolves in a solvent.
Entropy increases when a dissolved gas escapes from a solution
Can also relate surroundings to the system!
= - DHsystem / T
= DHsystem - TDSsystem
DGs are additive!
If not at standard conditions,
DG = DGo + RT ln Q
(Equilibrium is characterized by the inability to do work.)
At equilibrium, Q = K and DG = O
Therefore, substituting into previous equation gives 0 = DGo + RT ln K and
DGo = - RT ln K (can use Kp or Kc)
2020.5 Thermodynamics and Time describe synthetic chemistry, the making of molecules that is at the intellectual and economic center of chemistry, is that it is the local defeat of entropy.”