Gibb's Free Energy

Gibbs Free Energy (G)

A state variable, measured in KJ/mol

Gibbs realized that for a reaction, a certain amount of energy…

goes to an increase in entropy of a system and a certain amount goes to a heat exchange for a reaction

Standard pressure for gas

1 atm partial pressure

Pure liquids standard pressure

the liquid under a total pressure of 1 atm

Solutes standard concentration

1 M

Solids standard

the pure solid under 1 atm

What is standard temperature?

25 degrees celsius, 298.15 Kalvin

The Gibbs free energy is the maximum amount of non…

expansion work that can be extracted from a closed system

For many exothermic reactions, some of the heat released due to the enthalpy change…

goes into increasing the entroy of the surroundings, so it is not available to do work

Products and reactants are in equilibrium when their Gibbs free energies are…

equal

A chemical reaction will proceed in the direction of…

lower Gibbs free energy

a reaction will not proceed if the reaction produces an…

increase in Gibbs free energy

Negative DG values indicatite…

that a reaction is spontaneous

When DG is negative, what happens to forward reaction?

Forward reaction has excess energy and will occur spontaneously

When DG is positive, what happens?

there is not enough energy in the forward direction, and the BACKWARD reaction will occur

When DG is 0…

reaction is at equilibrium