how do you derive deltaG
To derive the change in Gibbs free energy (ΔG) for a reaction, you typically follow these steps:
1. Start with knowing the standard Gibbs free energy change (ΔG°) for the reaction. This value represents the change in Gibbs free energy under standard conditions, which are defined as a temperature of 298 K (25°C), a pressure of 1 bar (or 1 atm), and all reactants and products at their standard state.
2. Calculate the reaction quotient (Q) using the concentrations (or partial pressures) of the reactants and products at the given conditions. This can usually be obtained from the initial conditions or the given problem.
3. Use the equation ΔG = ΔG° + RT ln(Q), where R is the ideal gas constant (8.314 J/(mol·K)) and T is the temperature in Kelvin, to calculate ΔG.
- ΔG: Change in Gibbs free energy under non-standard conditions
- ΔG°: Change in Gibbs free energy under standard conditions
- R: Ideal gas constant (8.314 J/(mol·K))
- T: Temperature in Kelvin
- ln: Natural logarithm
- Q: Reaction quotient, calculated using the concentrations (or partial pressures) of the reactants and products
By plugging in the given values and solving the equation, you can obtain the change in Gibbs free energy (ΔG) for the reaction under non-standard conditions.