A pure substance is a substance with a very low concentration of impurities: reagents for analysis, ultra pure reagents, nuclear grade materials, electronic grade materials, certified reference...
The solute dissolves in the solvent. The solvent is generally considered that which there is more of in the mixture. For mixtures near 50:50 the distinction is arbitrary but the liquid is generally...
It seems that the phrase you are looking for is "physical property". Density depends on several factors, such as: is the substance a solid, liquid or gas (the same substance will have vastly...