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Entropy/Free Energy
Chem 2
Term | Definition |
---|---|
Chemical Thermodynamics | provides info about equilibrium and whether a reaction is spontaneous |
Exothermic (∆H) | ∆H<0 |
Endothermic (∆H) | ∆H>0 |
In order to be spontaneous the energy... | of the product must be less than the reactant |
entropy | randomness vs orderliness of a system |
A spontaneous process results in.... | an increase in the entropy of the universe (DeltaS>0) |
A perfect crystal has... | 0 entropy and 0 K |
Enthalpy is measured in... | Kilojoules |
Entropy is measured in... | joules |
entropy depends on... | Phase, complexity, weight, and temp |
an increase in temp results in... | an increase in entropy |
entropy of pure elements | 0 |
an entropic process is spontaneous if... | Delta S > 0 |
(∆S (sur) = | -Delta H (sy)/ T |
∆S(un)= | Delta S (sy) + (-Delta H/T) |
Spontaneous at all temperatures | Exothermic and positive entropy |
Spontaneous at lower temperatures | Exothermic and negative entropy |
Spontaneous at high temperatures | Endothermic and positive entropy |
Never spontaneous | Endothermic and Negative entropy |
Gibbs Free energy equation | Delta S(un)= DeltaH- T x Delta S |
Forward and Spontaneous reaction | Delta G is large and negative |
Forward and non-spontaneous | Delta G is large and positive |
product favored | -Delta H, +delta S, -delta G |
Reactant favored | +Delta H, -delta S, +delta G |
Temp dependent | -,- or +,+ |
Positive DeltaS | Spontaneous |
Negative DeltaS | not spontaneous |