There is just one ingredient in a pure element or compound; no additional substances are present. Impure materials can be made up of different elements, compounds, or elements plus compounds. Other than NaCl, there are no other particles in the salt. Salt is a pure material in this sense. When you talk about impure substances, you’re talking about a mixture of molecules in one material.
The look and content of a homogenous mixture are consistent throughout. The term ‘solution’ is used to describe a wide range of homogenous mixes. A heterogeneous mixture is made up of components or stages that are obviously diverse. Gas, liquid, and solid are the three phases or states of matter.