Luminol Do Lab Report

556 Words 3 Pages
What Does Luminol Do?
Luminol is used to reveal traces of blood in crime scenes, using a light producing chemical reaction, between many chemicals, and hemoglobin. It is a powdery compound made up of carbon, hydrogen, nitrogen, and oxygen. Mixing C8H7N3O2 (luminol) with H2O2 (hydrogen peroxide), causes it to become a liquid. Hydrogen peroxide and luminol are the two main parts of this chemical reaction. To produce a strong glow, a catalyst needs to be present. A catalyst is a substance that increases the rate of a reaction, without undergoing that reaction. When it is used in forensics, the catalyst is iron, found in hemoglobin, therefore accelerating a chemical reaction. Compounds react with the oxidizing agent, replacing nitrogen and hydrogen
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Phosphorescence re-emits the light very slowly in the dark. Phosphorescence and fluorescent are very similar in the process, expect for the fact that in a phosphorescence reaction, light is emitted slower than in a fluorescent reaction. Fluorescence takes about 10-8 seconds to emit the light, but phosphorescence takes 10-3 seconds. Phosphorescent works with the energy bands in crystalline materials such as luminol, and they are the large number of closely spaced energy levels. They are the collection of individual energy levels around an atom. They deal with the conduction in crystalline materials. Conduction band determine the electrical conductivity of a solid, it is usually the lowest range. Valence band is the highest range, and in this band electrons are usually present at absolute zero (lower limit of thermodynamic temperature scale) temperature. Impurity state energy band is located between the conduction and valence energy bands. When phosphorescent occurs, the absorbed energy goes through a high energy state, causing the atoms to become excited. When the atoms are excited, they jump to a higher energy level. For the atoms to return to a lower energy level they need to decrease the energy of the atoms, returning back to normal. When they are moving to a lower energy level, the energy that excited them is released in tiny particles called photons. The light that phosphorescence creates can last for seconds, or hours. Between the ground level, and the excited level, is a level of intermediate energy. This level is called a metastable level, or an electron trap. Transitions between the metastable and other levels are forbidden. When an electron falls from the excited level, to the metastable level, it is stuck there until it makes a “forbidden” transition, or is excited back to the transition level. This can cause thermoluminescence. Thermoluminescence is the emission of light, from some minerals and other

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