Free Energy Flashcards
- Define Gibbs free energy, and describe its relation to spontaneity. - Calculate free energy change for a process using free energies of formation for its reactants and products. - Calculate free energy change for a process using enthalpies of formation and the entropies for its reactants and products.
1
Q
Gibbs Free Energy
A
The energy in a system available to do useful work at constant temperature and pressure.
2
Q
Free Energy Change (ΔG)
A
The change in Gibbs free energy during a process. It predicts spontaneity.
ΔG < 0: Spontaneous
ΔG > 0: Nonspontaneous
ΔG = 0: System is at equilibrium
3
Q
Standard Free Energy of Formation ΔG°f
A
The free energy change when 1 mole of a compound forms when its elements in their standard states (25°C, 1 atm). Elements in their most stable forms
- like O₂ gas have ΔG°f = 0.
4
Q
What are the differences between Gibbs free energy and ΔG?
A
- Gibbs free energy is the total available energy while ΔG indicates whether a reaction will proceed without external energy.
- ΔG°f specifically refers to forming a substance under standard conditions, unlike ΔG, which applies to any conditions.
5
Q
What are the similarities between ΔG°f, ΔG and Gibbs Free Energy?
A
- All relate to the system’s energy changes and spontaneity.
- ΔG and ΔG°f both help determine if a reaction is favorable under certain conditions.
6
Q
What are their applications?
A
- ΔG helps predict whether a reaction will occur naturally.
- ΔG°f is used in calculating ΔG for complex reactions by combining free energies of formation for reactants and products.
- In summary, Gibbs free energy provides a tool for determining whether a chemical process can proceed on its own or needs intervention.
