An equilibrium in which every reactant and product is in the same phase is described as:

1. Equilibria are sorted by whether the species share a phase. 2. A homogeneous equilibrium is one in which all reactants and products are present in the same phase. 3. Any catalysts present are counted in that requirement too. 4. A heterogeneous equilibrium spans more than one phase. _Source: OpenStax Chemistry 2e (CC BY 4.0), Ch 13 'Fundamental Equilibrium Concepts', sections 13.1-13.4_