Thermodynamics Flashcards
Entrophy (S)
The state of disorder of a system ⬆️ disorder = ⬆️ entrophy Focus' on starting and ending state Reversible reaction = S= q/T Non-reversible = S > q/T
Open systems
Can exchange matter/energy with it’s surroundings
Closed system
Can only exchange energy with its surroundings
Isolated system
Cant exchange both energy and matter with its surroundings
Heat (q)
Energy dispersed as random motion
Work (w)
Energy dispersed as non-random motion
w = -PV
If a system expands V is positive
Internal energy (U)
Total energy in a system
U = change in internal energy, U final - U initial, 0 energy gained
Spontaneous reaction
Occurs naturally
No need for input w
Non-spontaneous reactions
Needs input w to occur
Happens because there is a natural tendency for disorder
Gibbs free energy
Balancing effect between enthalpy and entrophy
G = H-TS
At thermodynamic equilibrium G=0
Standard entrophy change
S=sumS products - sumS reactants
Enthalpy (H)
Energy used/released within a system at a constant pressure
H= U+PV
H= q
H 0 = endothermic
Standard free energy change
G = H-TS
Free energy formation
Change when a compound in its standard state is prepared from its elements in their standard states
Reaction quotient (Q)
Defines reactants and product concentration ratio at any stage of the chemical transformation
