📚 What is Standard Gibbs Free Energy?
Standard Gibbs Free Energy ($ \Delta G^\circ $) refers to the change in Gibbs Free Energy when a reaction occurs under standard conditions. These standard conditions are typically defined as 298 K (25°C) and 1 atm pressure, with all reactants and products in their standard states (usually 1 M concentration for solutions and pure form for solids and liquids).
- 🌡️ Standard conditions are usually 298 K (25°C) and 1 atm.
- 🧪 All reactants and products are in their standard states.
- 📏 Denoted by the symbol $ \Delta G^\circ $.
🔥 What is Non-Standard Gibbs Free Energy?
Non-Standard Gibbs Free Energy ($ \Delta G $) refers to the change in Gibbs Free Energy when a reaction occurs under non-standard conditions. This means the temperature, pressure, or concentrations of reactants and products are different from the defined standard conditions.
- 📈 Refers to any conditions that are not standard.
- ⚗️ Concentrations of reactants and products are not necessarily 1 M.
- ⚙️ Temperature and pressure may vary.
- 🏷️ Denoted by the symbol $ \Delta G $.
🆚 Standard vs. Non-Standard Gibbs Free Energy: The Key Differences
Here’s a table highlighting the key distinctions:
| Feature |
Standard Gibbs Free Energy ($ \Delta G^\circ $) |
Non-Standard Gibbs Free Energy ($ \Delta G $) |
| Conditions |
Standard conditions (298 K, 1 atm, 1 M) |
Non-standard conditions (any conditions not standard) |
| Reactant/Product States |
Reactants and products are in their standard states |
Reactants and products may not be in their standard states |
| Equation |
$ \Delta G^\circ = -RT \ln K $ |
$ \Delta G = \Delta G^\circ + RT \ln Q $ |
| Equilibrium Constant |
Related to the equilibrium constant (K) |
Related to the reaction quotient (Q) |
🔑 Key Takeaways
- ✅ Standard Gibbs Free Energy provides a reference point for comparing reactions.
- ✨ Non-Standard Gibbs Free Energy tells us the spontaneity of a reaction under specific, non-standard conditions.
- 🧮 The relationship between $ \Delta G $ and $ \Delta G^\circ $ is given by the equation: $ \Delta G = \Delta G^\circ + RT \ln Q $, where R is the gas constant, T is the temperature, and Q is the reaction quotient.