Explain the significance of positive and negative values for each thermodynamic quantity in the free energy equation. (enthalpy change, entropy change, and free energy change)
I think this is something you can find in your text/notes. If not, explain what you don't understand about each and perhaps we can help. We shall be happy to critique your thinking.
The free energy equation, also known as Gibbs free energy equation, is derived from the laws of thermodynamics and is used to determine the spontaneity and equilibrium of chemical reactions. It is expressed as:
ΔG = ΔH - TΔS
where:
- ΔG is the change in Gibbs free energy, which determines whether a reaction is spontaneous (ΔG < 0) or non-spontaneous (ΔG > 0).
- ΔH is the change in enthalpy, which represents the heat exchanged between the system and the surroundings during a reaction.
- ΔS is the change in entropy, which measures the disorder or randomness of a system.
- T is the temperature in Kelvin at which the reaction is occurring.
Now, let's discuss the significance of positive and negative values for each thermodynamic quantity in the free energy equation:
1. Enthalpy change (ΔH):
- A positive ΔH value indicates that the reaction is endothermic, meaning it absorbs heat from the surroundings.
- A negative ΔH value indicates that the reaction is exothermic, meaning it releases heat to the surroundings.
2. Entropy change (ΔS):
- A positive ΔS value indicates that the disorder or randomness of the system increases during the reaction.
- A negative ΔS value indicates that the disorder or randomness of the system decreases during the reaction.
3. Free energy change (ΔG):
- A negative ΔG value indicates that the reaction is spontaneous and will occur without any external intervention. This means the reaction is energetically favorable, and the system's free energy decreases.
- A positive ΔG value indicates that the reaction is non-spontaneous and will not occur naturally. This means the reaction is energetically unfavorable, and the system's free energy increases.
- A ΔG value of zero indicates that the reaction is at equilibrium, where the rates of the forward and reverse reactions are equal.
To determine the values of ΔH, ΔS, and ΔG for a specific reaction, experimental data or thermodynamic calculations are usually required. These values can be found in thermodynamic tables or determined using various techniques in thermodynamics, such as calorimetry and entropy calculations.