版权所有：华东理工大学物理化学教研室 8 8.1 Definitions 2). The number of components, C No chemical reactions The pure water is a one-component system, C = 1, because we need only the species H2O to specify its composition. Similarly, a mixture of ethanol and water is a two-component system, C = 2: we need the species H2O and C2H5OH to specify its composition. When no reaction takes place, the number of components is equal to the number of constituents.版权所有：华东理工大学物理化学教研室 8 8.1 Definitions 2). The number of components, C No chemical reactions The pure water is a one-component system, C = 1, because we need only the species H2O to specify its composition. Similarly, a mixture of ethanol and water is a two-component system, C = 2: we need the species H2O and C2H5OH to specify its composition. When no reaction takes place, the number of components is equal to the number of constituents