Free energy is a measure of the energy available to do work in a system. It is directly related to equilibrium, as a system at equilibrium has zero free energy because there is no potential for change or work to be done.
Free energy and entropy are both measures of a system's energy, but they represent different aspects. Free energy takes into account both the system's internal energy and the energy required to do work, while entropy is a measure of the system's disorder.
Free energy can be calculated using the equation ΔG = ΔH - TΔS, where ΔG is the change in free energy, ΔH is the change in enthalpy, T is the temperature in Kelvin, and ΔS is the change in entropy.
A negative value for free energy (ΔG < 0) indicates that a reaction is spontaneous, meaning it will occur without the addition of external energy. A positive value for free energy (ΔG > 0) indicates that a reaction is non-spontaneous and will only occur with the input of external energy.
Yes, the sign of free energy (positive or negative) can be used to predict the direction of a reaction. A negative value for free energy indicates that the reaction will proceed in the forward direction, while a positive value indicates that the reaction will proceed in the reverse direction.