Engineering Chemistry Practice Test: Criteria of Purity and Characterization of Materials — Flashcards

Criteria of Purity and Characterisation of Materials topics include: Melting and boiling point, conductivity, particle size measurement and viscosity.

The purity of a substance can be determined by checking its melting point or boiling point. A pure substance has a fixed melting point or boiling point at constant pressure. If a substance is impure, its melting and boiling point will change. 

The most accurate means of determining the purity of a substance is through the use of analytical methods. These methods mostly involve chemical analysis, which can pinpoint the presence, identity and amount of impurities in the sample. 
Materials characterization is the process of studying and understanding the physical, electrical and chemical properties of materials. It is an essential part of materials engineering analysis that helps to identify the right material for specific applications. 

Here are some techniques for characterizing materials:
Chromatography: A useful technique for determining the purity of a substance. If a substance is pure, it will only produce one spot because it is only made of one substance. Impure substances will produce two or more spots.
Distillation: A frequently used process in chemical analysis for characterizing materials and extracting specific components from a whole matrix by producing a purity index.
Sublimation: A method of purifying solid organic matter. Sublimation products have a high purity, and this method is particularly suitable for purification of moisture-prone solutions or with solvent decomposition of substances. 
 

Related Test: Engineering Chemistry Practice Test: Materials and their Properties