What is Gibbs Free Energy?
For a simple definition, Gibbs free energy can be described as
A measure of the amount of energy available to do work.
Gibbs free energy is used in chemistry to help determine and predict ahead of time whether a chemical process is spontaneous or non-spontaneous.
You might be wondering what’s the advantage of that. There are many applications in life that we need advance knowledge what to expect. For example in the manufacturing of products – if you have no clue which direction your process is going, then you might produce something totally unexpected and waste a lot of resources.
In a spontaneous process, it happens automatically.
In a non-spontaneous process, energy input is necessary to trigger off a process. You need activation energy.
The Gibb’s Free Energy is simply a method of telling whether a chemical process will take place spontaneously or non-spontaneously.
- The Gibbs free energy calculates the amount of energy available in a system to do work like carrying out a chemical reaction.
- Gibbs free energy is only applicable for systems under constant temperature and pressure.
- The Gibbs calculation allows you to determine whether a process is spontaneous or not.
- Gibbs calculation uses the relationship between Ethalpy and Entropy in a system to determine the spontaneity of a process.
HOW TO DETERMINE IF A REACTION IS SPONTANEOUS
For notes on spontaneity, please click here >>
Gibbs Free Energy is the energy associated with a chemical reaction that can be used to do work.
∆H – Enthalpy is the change of heat in a system due to chemical reaction measured in joules
∆S –Entropy is the measure of energy dispersal in j/k
∆G – Gibbs free energy
∆Gsystem = ∆Hsystem – T∆Ssystem
- If ∆G is negative – spontaneous reaction.
- If ∆G is positive – non spontaneous reaction.
Equation representing the reaction occurring under standard condition (298K and 1atm)