2. Stoichiometry. Material balances in ideal reactors

2.1 Composition of a changing environment

Consider a phase in which a chemical transformation is taking place. The state of this phase is defined when we know the pressure p , the temperature T and the chemical composition at all points. We will denote by A ₁ , A ₂ , ..., A _j , ..., A _s the chemical constituents (known as active ) that take part in the reactions. There may also be inerts, which do not take part (index I ).