8 posts • Page 1 of 1
I'm still unsure as to exactly what Gibbs free energy is. I know it's expressed in terms of the difference between enthalpy and entropy, but is that all we can say about it? Is there nothing specific, like how enthalpy is heat and entropy is "disorder"?
Gibbs free energy is a representation of spontaneity it the likeliness for which a reaction will occur on its own. So, as entropy can be called "disorder," Gibbs's free energy can be referred to as how spontaneous a reaction is. However, like "disorder," Dr. Lavelle does not love using spontaneity because students often assume this means quickness, but it has nothing to do with speed. It is just how likely or favorable a reaction will occur without help.
Another way to think of entropy is the a state of relaxed disorder. Since Gibbs free energy is the amount of energy free do do work and the change in Gibbs is the energy that was needed to do work (or make a reaction happen) it is affected by the amt of heat or energy coming and leaving the system (which is enthalpy). Also if entropy isn’t very high, the change in Gibbs will be smaller and therefore spontaneous, because the more random the system more likely the molecules will meet and interact naturally.
The way i think of it is that changing the state of a system requires energy (delta H) but when molecules exchange heat with its surroundings some molecules spontaneously arrange themselves so that the energy needed to change the state is less than the total energy required. The energy you actually have to put in is gibbs free energy that you added to the system.
Gibbs free energy is amount of energy available to do work, and it can be used to predict whether a reaction will be spontaneous or not. If delta G is negative, then the reaction will be spontaneous in the forward reaction (meaning that the reactants have enough energy to move the reaction forward). If delta G is positive, then the reaction will not be spontaneous in the forward reaction (meaning that the products have more energy than the reactants).
Who is online
Users browsing this forum: No registered users and 2 guests