Grand canonical ensemble

The grand canonical ensemble is a way scientists model systems where particles can enter or leave, like a gas in a flexible container connected to a reservoir. It considers not only the energy of the system but also how many particles are present, accounting for both temperature and chemical potential (which relates to particle exchange). This approach helps predict properties like average particle number and energy, making it useful for studying open systems in equilibrium with their surroundings, such as chemical reactions or devices with variable particle content.