Chemistry Lab: Examining Dyes And Dying

Laboratory 2: Examining Dyes and Dying Introduction
Dyes, which used on material such as cotton, silk, wool, and nylon appears to have color due to the partial light absorption in the visible region of the electromagnetic spectrum. Chromophores, derived from Greek, Chroma meaning color and phoros meaning bearer makes light absorption feasible. Dyes contain both chromophore molecules and auxochrome molecules; chromophore molecules include unsaturated groups, for instance carbon-carbon double bonds, azo, nitro, carbonyl, or akyl. Auxochrome molecules are comprised of groups such as amino, alkoxy, phenolic, sulfonyl, and carboxyl. Some examples of dyes are Malachite Green-which includes an amine group and ammonium, Para red-which includes nitro, azo benzene, phenol, and Congo red which includes an amino group, azo benzene, and sulfonate. Some molecules are colorless (azo compounds) or do not absorb dyes easily, therefore they conjugate. To understand conjugation, it is important to understand groups connect in such a way that makes them form a system, also the greater the amount of conjugation in a molecule the more the absorption of the molecule is
Lastly when it comes to materials it is ideal for them to be color fast, which means they are resistant to fading and running, to ensure this a mordant can be added to bind the fiber and dye (the mordant is