Final answer:
The change in Gibbs free energy (ΔG) for a process is the maximum non-expansion work possible under constant temperature and pressure, associated with spontaneous processes, equilibrium, and calculations of reaction spontaneity.
Step-by-step explanation:
The change in Gibbs free energy (ΔG) for a process is the maximum amount of non-expansion work that the system can do under constant temperature and pressure. When a process occurs spontaneously at constant temperature and pressure, the Gibbs free energy decreases, which correlates with an overall increase in entropy. The key relationship is: ΔG = Gibb's free energy change; ΔG < 0 for a spontaneous process; and ΔG = Wmax for the maximum work done by the system.
ΔG provides valuable insights into the spontaneity of a reaction or physical process by considering the system's enthalpy (H), entropy (S), and temperature (T), as defined by the equation G = H - TS. If ΔG = 0, the system is at equilibrium, implying no net change. ΔG values can be calculated either under standard conditions or adapted to non-standard conditions, providing information for both experimental and practical applications of thermodynamics.