Gibbs free energy change of a reaction under
nonstandard conditions
Review standard state
- defined as:
1. For a gas, standard state is 1 atm
2. For substance w aqueous solution, standard state is
1 m
3. For element or compound, standard state is most
stable form at 1 atm and temp around 25c
Nonstandard state and reaction mixture
O
- sign of standard free energy change ( g rxn) tells
direction of spontaneous rxn when both reactants and
products are present at standard state conditions
,Gibbs free energy change ( Sg) for nonstandard condition
- to get free energy at conditions other than standard
states, we can use following: natural log
nonstandard
d
G
8.31pSThtem
state
=
Go+RFInQxReaction grottent
↑standard state
Echange forRxn w/all Reactants products at
Temp T
Free energy changes as a reaction proceeds
- we know that as rxn proceeds, composition of reacting
mixture changes. Bc of this, GFE of system changes
continuously
*
lowest GfE is ategullibRNM
nonstandard conditions
Review standard state
- defined as:
1. For a gas, standard state is 1 atm
2. For substance w aqueous solution, standard state is
1 m
3. For element or compound, standard state is most
stable form at 1 atm and temp around 25c
Nonstandard state and reaction mixture
O
- sign of standard free energy change ( g rxn) tells
direction of spontaneous rxn when both reactants and
products are present at standard state conditions
,Gibbs free energy change ( Sg) for nonstandard condition
- to get free energy at conditions other than standard
states, we can use following: natural log
nonstandard
d
G
8.31pSThtem
state
=
Go+RFInQxReaction grottent
↑standard state
Echange forRxn w/all Reactants products at
Temp T
Free energy changes as a reaction proceeds
- we know that as rxn proceeds, composition of reacting
mixture changes. Bc of this, GFE of system changes
continuously
*
lowest GfE is ategullibRNM
