The Importance Of Chemistry In Forensics PDF

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The Importance Of Chemistry In Forensics...

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The Importance Of Chemistry In Forensics In forensics, there is a lot of chemistry involved. The various processes that a forensic procedure requires includes basic skills and knowledge from chemistry. Since chemistry and forensics are so closely related, many of the same concepts are used in each field. That is why it is important to go into more detail to see what type of chemistry has to deal with this. It is very rare that there is a forensics specialist investigating a crime scene without there being any type of chemistry involved. Chemistry is to forensics as oxygen is to people; meaning it is required to function properly. Many aspects and elements of chemistry can be found all throughout forensics. Forensic science is the application of science and its properties in order to analyze and study material from a crime. The material can be a physical item that can be studied thoroughly. For example, a forensic scientist needs to be able to connect evidence from the crime scene to the crime itself. They study various kinds of evidence that may include chemistry and other kinds of science in their research. These scientists analyze physical evidence such as DNA, fingerprints, blood, and other kinds of substances. The use of forensics in solving crimes is useful in many ways and often helps solve the crime. (Funk

& Wagnalls, n.d.) One can see that forensics is mainly applied in the crime field. A forensic science technician plays a big role in the study of forensics. Forensic scientists can study their evidence by participating in a laboratory analysis or being at the actual crime scene. The lab is where all of the chemical and physical analysis of the evidence occurs. The advancement of technology helps these scientist increase the use of the forensic information found. The recent popularity of forensic crime scene shows indicate a rapid growth in this field of study (Reese, 2015). In forensics, one has to be able to successfully identify a substance based on its chemical and physical properties. Whether it is a fingerprint, DNA, or even a footprint, the technician must be able to thoroughly study it. For example, there are different kinds of fingerprints such as visible, latent, and impression. In order to examine latent fingerprints, must use different techniques in order to understand who’s it is. After examining the unique pattern, the technician will be able to track down the person (Sullivan, 2003). Not only this, but in forensics, one must use the physical properties of a substance they see in order to identify it.

One important step for these workers includes the act of observing. The physical evidence found at a crime scene can be any kind of matter including solids, liquids, or gases. This requires the understanding of the properties of matter in which it can exist. By carefully observing the physical and chemical properties of the substance, the scientist can be one step closer to solving the crime. Chemical reactions is a primary method of identifying evidence. Detectives use chemicals that are known to react with illegal drugs; which creates chemical reactions that will react when mixed. They represent the chemical reactions by writing a chemical equation. There are different types of chemical reactions; single, double, synthesis, combustion, decomposition and redox reactions. They combine the reactants which produce the products of the equation. Moles are used in equations to go from one substance to another. Converting between substances is necessary for measuring appropriate quantities of the reactants. This can be done using Avogadro’s number which is equal to one mole. One mole is equal to 6.022x10^23(Johll, 2007). Stoichiometry is used to convert between balanced equations. When stoichiometry is used with balanced equations we can use it to find the

maximum amount of substance that can be produced from another. Stoichiometry calculations that are often used in the laboratory, are the number of grams that can be produced from one substance. It can also be used to determine the amount of grams that can be produced from a substance(Johll, 2007). Isotopes are an important part of solving chemical mysteries. They are commonly used in the laboratory to investigate how each of the steps in a chemical reaction occurs. Isotopes of elements have the same atomic number, but are different by their mass number. One example of it being used in forensics is that a company may produce their explosions with their isotopes placed in a specific way. If an explosive were used in a crime, then the forensic scientist could link it back to where it came from. Even though this is not practiced in the United States, it is still being exercised in other countries. The relative abundance of isotopes is the measure and mass of the isotopes in an element. Scientists can determine the atomic mass of the element by natural abundance. (Johll, 2007) The two types of chemical bonds that form within a compound are known as covalent and ionic bonds.Covalent bonding occurs between two nonmetals while an ionic compound occurs between a metal and

a nonmetal. These two types of compounds must be handled differently when they are analyzed and used as evidence. (Johll, 2007) Two distinct chemical reactions are metathesis reactions which are also known as double displacement reaction. The two products that it produces are what gives it the name. The reactants exchange with each other thus creating the two new compounds. The first of the double displacement reactions is a precipitation reaction; this reaction forms a solid from two aqueous reactants. The precipitation reaction AgCl is used in the forensic field to develop fingerprints. The second double displacement reaction is a neutralization reaction. This reaction occurs when a base reacts with an acid which creates a salt and water(Johll, 2007). Elements are used all throughout forensics and especially when it comes to solving a crime. The periodic table helps forensic chemist solve their crime by investigating the crime scene. The crime scene can consist of blood, animal hair, paint, or even gunshot residues. But it is unusual to find a primary form at a crime scene because there are usually other types of elements that react with other substances and they form different types of compounds. When forensic chemist get to

this point they have to find a way to separate these types of compounds and it’s not an easy task to separate these elements. But there is one way to separate them and it’s called chromatography. Chromatography separates colors and it’s also known as the “color writing”. This type of method is mainly used when there trying to identify drug, explosives, narcotics, and fibers at a crime scene. In order for the results to come out right the forensics specialist have to be very careful when doing these type of procedures. That’s why in every forensics lab everyone has a specific job and everyone is in charge of what they are assigned to do so there won 't be any mistakes. That’s why it’s important for forensics to learn the periodic table by heart because in every crime scene they might get in there is always going to be some sort of chemical or anything else that has to do with the elements in the periodic table (Johll, 2007) . Chemical reactions also occur within the evidence. This is why it is crucial to preserve the evidence at the state that it is found in. Most of the time, items are preserved in a special container in order to keep it from going through the process of a chemical change.it is important to understand their chemical properties in order to put it in the correct container that is appropiate. This means that the temperature,

pressure, and concentration must remain consistent throughout time. However, a chemical change is sometimes required in order to understand the substance better. For example, some chemicals may need to be introduced to fingerprints which may not be visible to the eye. When chemicals are added to it, it may aid in making it more visible for the technicians(Johll, 2007). When a chemical or physical reaction occurs, the motion of molecules and atoms change within the substance. According to the law of conservation of mass, matter cannot not be created nor destroyed. So when the substance changes by a chemical reaction, the only event that takes place is the rearranging of the atoms. The substance itself has the same number of atoms still available, but they have moved into a different molecular arrangement (Johll, 2007). The molecule’s motion within the substance varies depending on the state of matter. Gas particles are constantly in a random motion. The particles within a liquid have a limited motion range, so they stay packed closely in a volume. A solid has vibrating motions that keep the particles in place (Buthelezi, 2008). It is important to have these in mind when analyzing materials because of the fact that they can change depending on its environment. Since heat and energy can be

taken away and added on, the state of matter can change along with it. (Johll, 2007). Having this knowledge is very useful for forensic technicians because most of the evidence that they come in contact with are materials in a physical state. Once they have tested the pH of the sample, they can then also test the pH of the crime scene and compare the two samples. By comparing the two samples the forensic chemists will then be able to weigh the result of the pH test and decide whether or not there is a link between the two samples. In addition to linking a suspect to the crime scene, pH of soil can also tell possible places the suspects went before they were at the crime scene. By knowing where certain suspects were, you will be able to narrow down your suspects based on where the soil has linked them and their alibis (Ashley). As there are many connections between the world of chemistry and the world of forensics, pH can be a great way for forensic chemist to examine certain samples of trace evidence. In chemistry, we use pH to contrast and compare the acidities of different solutions, and when we do this we can determine the solution to be either acid, neutral, alkaline, or basic.The reason why solutions are different, as in being acid, basic, neutral, or alkaline, is due to the hydrogen ions activity in

the solution. (Senese, 2010) One example of trace evidence that forensic chemist use pH to test is soil. This is because soils have different pH levels, and when they can get a soil sample they can test its pH. Testing soil can be done by performing a pH test, and a pH test consist of putting a small amount of soil in distilled water then dropping some on litmus paper. Once the drop is on the litmus paper you can then observe the color the paper changes to. The pH will range between one and fourteen with seven being neutral, closer to one being acidic, and closer to fourteen being basic. This test is one that is simple, yet it can help to determine the fault of a crime(Ashley)....