free energy
the portion of a systems energy that can perform work when temperature and pressure are uniform throughout the system as in a living cell
chemical reaction
∂G= ∂H- T∂S
∂H
enthalpy
-total energy change
∂S
entropy
T
absolute temperature measured in Kelvins
Cº + 273
negative ∂G
spontaneous?
spontaneous
- loss of free energy
- more stable b/c no energy to change
positive ∂G
non spontaneous
0 ∂G
non spontaneous
stability
all systems move towards greater stability
lower ∂G
state of maximum stability
equilibrium
G is at lowest possible value
how does free energy come from equilibrium
when reaction is somehow pushed away from equilibrium
G becomes more positive
spontaneous and work at equilibrium
- -reactions never spontaneously move away fro equilibrium
- -b/c they aren’t spontaneous, they can’t do work
–a process is only spontaneous and can perform work when it is moving towards an equilibrium
g<0
spontaneous
- H>
- releases energy
- exergonic
- S<
- increase entropy (less organized)
g>0
not spontaneous
- H<
- stores energy
- endergonic
- S>
- decrease entropy (more organized)
cellular respiration
spontaneous
- exergonic
- less organized
- increase entropy
photosynthesis
non spontaneous
- endergonic
- more organized
- decrease entropy
