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The two main standalone spectroscopy techniques for forensic chemistry are FTIR and AA spectroscopy. FTIR is a nondestructive process that uses infrared light to identify a substance. The attenuated total reflectance sampling technique eliminates the need for substances to be prepared before analysis. [28]
A chemical substance is a unique form of matter with constant chemical composition and characteristic properties. [1] [2] Chemical substances may take the form of a single element or chemical compounds. If two or more chemical substances can be combined without reacting, they may form a chemical mixture. [3]
A compound can be transformed into a different substance by a chemical reaction, which may involve interactions with other substances. In this process, bonds between atoms may be broken or new bonds formed or both. There are four major types of compounds, distinguished by how the constituent atoms are bonded together.
The two basic conceptual foundations of forensic identification are that everyone is individualized and unique. [2] This individualization belief was invented by a police records clerk, Alphonse Bertillon, based on the idea that "nature never repeats," originating from the father of social statistics, Lambert Adolphe Jacques Quetelet.
The alkene called but-2-ene has two isomers, which the chemical formula CH 3 CH=CHCH 3 does not identify. The relative position of the two methyl groups must be indicated by additional notation denoting whether the methyl groups are on the same side of the double bond ( cis or Z ) or on the opposite sides from each other ( trans or E ).
The chemical composition of a mixture can be defined as the distribution of the individual substances that constitute the mixture, called "components". In other words, it is equivalent to quantifying the concentration of each component. Because there are different ways to define the concentration of a component, there are also different ways to ...
In a synthesis reaction, two or more simple substances combine to form a more complex substance. These reactions are in the general form: A + B AB {\displaystyle {\ce {A + B->AB}}} Two or more reactants yielding one product is another way to identify a synthesis reaction.
Generally, a chemical species is defined as a chemical identity that has the same set of molecular energy levels in a defined timescale (i.e. an experiment). These energy levels determine the way the chemical species will interact with others through properties such as bonding or isotopic compositions.