CHEM1B - CH 19 Thermodynamics

State Functions

(+) ∆H

(+) ∆H

Endothermic

(-) ∆H

Exothermic

What is ∆H

Change in Enthalpy

What is ∆S

Change in Entropy (disorder)

(+) ∆S

Entropically Favorable

(-) ∆S

Entropically Unfavorable

What is ∆G when ∆H is (+) and ∆S is (+)?

At high temperatures, ∆G is spontaneous (-).

At low temperatures, ∆G is nonspontaneous (+)

What is ∆G when ∆H is (-) and ∆S is (-)?

At high temperatures, ∆G is nonspontaneous (+).

At low temperatures, ∆G is spontaneous (-)

What is ∆G when ∆H is (-) and ∆S is (+)?

∆G is spontaneous (-) at all temperatures

What is ∆G when ∆H is (+) and ∆S is (-)?

∆G is nonspontaneous (+) at all temperatures

∆G, ∆H, and ∆S are all state functions. Define state functions.

They are path independent; follow displacement, meaning the value is independent of the path chosen

Square Planar Complexes

Coordination Number: 4, d8 electron configuration

Always low-spin (fill all lower levels before moving up)

Tetrahedral Complexes

Coordination Number: 4

Always high spin (half fill all orbitals first then go back and double)

High Spin Ligand

weak crystal field splitting energy, weak field ligand

Low Spin Ligand

strong crystal field splitting energy, strong field ligand

Diamagnetic

no unpaired electrons

Paramagnetic

>0 unpaired electrons

1st law of Thermodynamics

Energy cannot be created no destroyed, only transferred

2nd law of Thermodynamics

all spontaneous chemical processes increase entropy (disorder) of universe