Physical changes are observed when wax melts, when sugar dissolves in coffee, and when steam condenses into liquid water ( Figure 1.18).
A physical change is a change in the state or properties of matter without any accompanying change in the chemical identities of the substances contained in the matter. Other physical properties, such as the melting temperature of iron or the freezing temperature of water, can only be observed as matter undergoes a physical change. Some physical properties, such as density and color, may be observed without changing the physical state of the matter.
Familiar examples of physical properties include density, color, hardness, melting and boiling points, and electrical conductivity. A physical property is a characteristic of matter that is not associated with a change in its chemical composition. The characteristics that distinguish one substance from another are called properties.
0 kommentar(er)
