This change is not easily reversible. The weight of each reacting substance changes, although the total weight remains unchanged. There are a number of differences in the physical properties of chemical compounds which depend on the type of bonds which are present in the molecules of the compound. These differences are summarised in the table below. Comparison of Mixtures and Compounds Mixtures Properties related to those of the constituents.
Composition is variable.
Constituents can be mechanically separated. Compounds Properties need not be related to constituents. Composition is fixed and can be represented by a formula. Constituents cannot be mechanically separated. Component A component is a distinct chemical species in a mixture.