Analytical Chemistry
Analytical Chemistry is the branch of chemistry principally concerned with determining the chemical composition of materials, which may be solids, liquids, gases, pure elements, compounds, or complex mixtures. In addition, chemical analysis can characterize materials but determining their molecular structures and measuring such physical properties as pH, color, and solubility.
Wet analysis involves the studying of substances that have been submerged in a solution and microanalysis uses substances in very small amounts.
Qualitative chemical analysis is used to detect and identify one or more constituents of a sample. This process involves a wide variety of tests.
Ideally, the tests should be simple, direct, and easily performed with available instruments and chemicals. Test results may be an instrument reading, and observation of a physical property, or a chemical reaction. Reactions used in qualitative analysis may attempt to cause a characteristic color, odor, precipitate, or gas appear. Identification of an unknown substance is accomplished when a known one is found with identical properties. If none is found, the uknown substance must be a newly identified chemical. Tests should not use up excessive amounts of a material to be identified. Most chemical methods of qualitative analysis require a very small amount of the sample.
Advance instrumental techniques often use less than one millionth of a gram. An example of this is mass spectrometry.
Quantitative chemical analysis is used to determine the amounts of constituents. Most work in analytical chemistry is quantitative. It is also the most difficult. In principle the analysis is simple. One measures the amount of sample. In practice, however, the analysis is often complicated by interferences among sample constituents and chemical separations are necessary to isolate tthe analyte or remove interfering constituents.
The choice of method depends on a number of factors: Speed, Cost,
Accuracy, Convenience, Available equipment, Number of samples, Size of sample,
Nature of sample, and Expected concentration. Because these factors are interrelated any final choice of analytical method involves compromises and it is impossible to specify a single best method to carry out a given analysis in all laboratories under all conditions. Since analyses are carried out under small amounts one must be careful when dealing with heterogeneous materials.
Carefullly designed sampling techniques must be used to obtan representative samples. Preparing solid samples for analysis usually involves grinding to reduce particle size and ensure homogeneity and drying. Solid samples are weighed using an accurate analytical balance. Liquid or gaseous samples are measureed by volume using accurately calibrated glassware or flowmeters. Many, but not all, analyses are carried out on solutions of the sample. Solid samples that are insoluble in water must be treated chemically to dissolve them without any
Compress the safety bulb, hold it firmly against the end of the pipette. Then release the bulb and allow it to draw the liquid into the pipette.
Over 84 years ago the holocaust had just begun. And it ended about 12 years later. During this period a man with the name of Elie Wiesel had been imprisoned because of his religion. 5 years after his camp, he was staying in was liberated, he wrote a book called Night. For anyone who has ever read Night by Elie Wiesel, you may have picked up on some different reading styles throughout the story such as injections, similes and metaphors, cause and effects statements and uses of foreshadowing that helps to present an impressionistic style that is unique and empowers the comprehensive message in his influence memoir. World War II was a bad time in history, connected with the first war that happened. There were a lot of tragic events in the war. One of the events was the holocaust. During the holocaust not many people knew about it while it was happening. There wasn’t a lot of communication from people inside the camps. The majority of the people that were sent to the camps were jews and other races. They had no idea what was going to happen to them or what they were there for. Some did survive life in the camps,
Cu (aq) + 2NO3 (aq) + 2Na+ (aq) + 2OH- (aq) → Cu(OH)2 (s) + 2Na+ (aq) + 2NO3(aq)
In the novel Night by Holocaust survivor Elie Wiesel, multiple examples of oppression and expulsion of a group are utilized to show the consequences of inner turmoil regarding the good of humanity and the justice of God. The profound use of anecdotes on his experience in the camps extend the importance of his purpose in emphasizing the impact of this tumultuous event.
Going into details of the article, I realized that the necessary information needed to evaluate the experimental procedures were not included. However, when conducting an experiment, the independent and dependent variable are to be studied before giving a final conclusion.
Although the criminal justice system punishes those who have committed crimes against society, there are still flaws in the system that send innocent people to prison. Actual Innocence by Barry Scheck, Peter Neufeld, and Jim Dwyer, focuses on those problems connected to the incarceration of innocent people, as well as those who have been convicted and were ultimately exonerated. Confessions and racism are two major issues that are described in Actual Innocence that explain how these problems occur in our criminal justice system today and how innocent people are convicted of crimes.
Racial profiling is defined as targeting and further investigating a specific group of people due to that group’s race, religion, ethnicity, or national origin. The policy regarding racial profiling has been a great debate in the United States over the last few years due to tragic events that have been either a result of racial profiling, or an occurrence due to the lack of it. Like any other policy, racial profiling only began in order to protect the citizens of our country. Law enforcement is obligated to some degree to “racially profile” those who fit the criteria of targeted national threats. Unfortunately, like any other law enforced act, racial profiling can get out of hand and hurt more than save, which is obviously cruel and unfair. However, with the proper boundaries and examination, racial profiling can be more of an advantage than a disadvantage to our country and is, therefore, a policy that should continue. The
The procedure for this experiment can be found in Inorganic Chemistry Lab Manual prepared by Dr. Virgil Payne.
Racial profiling and the various problems that arise as a result of it bring up many controversial issues. Racial profiling is a topic that weighs heavy on the minds and opinions of many in this country. It has been the subject of many disagreements as to whether or not it actually exists. Some argue that certain races can’t see it because they never experience it, but a case can be made that all races experience it at some point. One of the most controversial is the debate of whether or not racial profiling is justified. One of the hindrances to finding an answer to this question is the fact that many agencies and departments in law enforcement refuse to cooperate with studies to
in todays society, an often recurring topic of racial profiling seems to plague the world through many political aspects. Racial profiling is one of the biggest injustices that individuals face in the world mainly because racism has always been something that plagued this world. Even though racial profiling is something that’s plaguing the world in today’s society, part of the biggest reason why this is such a problem is because of our worlds history. In many years past, different races use to do certain things that would often cause others to commit racial profiling. For example, since muslims were the cause of the devastation of 9/11, people will automatically have a natural reaction of fear when they are on an airplane. Racial profiling
Racial profiling had swept our nation it is the most conservation challenge in this new era. Though it has many forms of this practice, in law enforcement it is commonly associated with thinking a particular group or race are more likely to commit a crime than others. It has been depicted by its critics as discriminatory,
Throughout American history, there has been, without a doubt, an indisputable sense of racial tension among the various ethnic groups of the nation. These issues have been traced back since the establishment of the colonies and are still prevalent today in one form or another. Although the tension is no longer as intense as it was before, it continues to exist today in modern society in the form of racial profiling. Racial profiling can be defined as the use of race or ethnicity as criteria for suspecting someone of having committed an offense. In recent decades, a trend has been observed in which police forces have been distinctively targeting black and Hispanic Americans more often than other ethnic groups. Police departments have argued
Part 1-The Burner - Familiarize yourself with the gas burner. Recognize all parts and learn how to operate them properly. Learn how to safely light the gas burner, and control the flame. Clean up the lab station when finished.
With Taylor’s scientific approach decisions are based on science or exact measurements. Estimations made according to convenience are inaccurate and inefficient. Each job is broken down into smaller functions, intern analyzed and timed to the tenth of a second. Through the use of scientific method the best possible way to perform a function is established and put into practice until a time comes when a better method or tool is devised.
borate) and 1.0 g. of sodium hydroxide in 20 mL of warm water. It may