Question

why is a compound considered as pure substance but mixture is not considered as pure substance

Answer 1

In a scientific context, “pure” denotes a single type of material. Ostensibly, compounds contain more than one type of material. Yet both compounds and elements are considered pure substances. Pure compounds are created when elements combine permanently, forming one substance. For example, when the elements mercury and oxygen combine, and a chemical reaction takes place, mercury (II) oxide is created. Once mercury (II) oxide has been created, it is not possible to separate the mercury and oxygen used in its creation from one another.

 

Mixtures, on the other hand, are considered impure substances. A mixture is created when substances combine but no chemical reaction occurs. In general, a mixture can be separated into its original components, while a pure compound cannot.

Answer 2

A pure substance is made up of only one single element.

But a mixture consists of many elements that are compounds