Introduction:
The purpose of this experiment is to analyze the efficacy and accuracy in determining mass composition of copper in a penny using two methods: atomic absorption spectroscopy and ultraviolet-visible spectroscopy.
The “Copper” Penny
The penny is a common form of currency used in the United States, holding the monetary value of one cent. From 1793 to 1837 the penny was composed of pure copper. As the years passed, the percent composition of copper in the penny decreased. From 1837 to 1857, the penny was bronze; containing 95% copper and 5% zinc and tin. In 1857, it was 88% copper and 12% nickel for a brief period of time then went back to bronze until 1962, with the exception in 1943 when it was zinc-coated steel due to the demand of copper for the war effort. In 1962, the tin was removed making the penny 95% copper and 5% zinc until 1982 when the composition was drastically changed to 97.5% zinc and only 2.5% copper, commonly known as copper-plated zinc. In this experiment we will analyze the use of atomic absorption and ultraviolet-visible spectroscopy to determine the mass composition of copper in pennies before and after the drastic change in 1982.
Atomic Absorption Spectroscopy
Atomic absorption spectroscopy is a technique used to identify the presence and concentration of substances by analyzing the spectrum produced when the substance is vaporized and absorbs certain frequencies of light. In atomic absorption spectroscopy, the sample is decomposed into atoms by a source of heat, such as a flame. The flame not only atomizes the sample, but also gets rid of the solvent used to dissolve the compound so we can analyze only the desired atoms. The concentration of atoms in the vapor is measured by the absorption o...
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... Mint 1997-2014, n.d. Web. 26 Jan. 2014. .
Harris, Daniel C. Quantitative Chemical Analysis. 8th ed. New York: W.H. Freeman, 1999. Print.
"How the AAS Works." YouTube. Vic Space Sci Education Centre, 01 May 2011. Web. 26 Jan. 2014. .
"Atomic Absorption Spectroscopy (AAS) -." EasyChem. N.p., n.d. Web. 26 Jan. 2014.
"Ultraviolet/Visible Spectroscopy (UV-Vis)." YouTube. Royal Society of Chemistry, 28 Sept. 2008. Web. 26 Jan. 2014. .
Gallik, Stephen. "Spectrophotometry: Transmittance and Absorbance." Cell Biology OLM. N.p., n.d. Web. 26 Jan. 2014. .
Absorbance was defined as: log I_o/I where I_o is incident light and I is the transmitted light. Fluorescence emission spectrum is different from fluorescence excitation spectrum because it records different wavelengths of chemical s...
Between 2001 and 2006, there has been an increase of.6 cents for the reproduction of the penny. This increase displays economic problems that may lead to fatal ones. The penny is composed of 2% copper and 98% zinc. These elements are exponentially in demand, causing the price of these materials to skyrocket. Many Americans think the penny is putting our country in jeopardy with financial losses.
The color that was chose to be shined through the sample was purple. The spectrophotometer was set at a wavelength of 400nm to represent the purple color. It was zeroed using the blank meaning the spectrophotometer read zero as absorbance amount. The blank consisted of 5mL of water and 2.5 mL AVM and it was placed in cuvette. A solution with a known concentration of 2.0x10-4 M was used in the spectrometer. For this solution, 5 mL of the solution with 2.5 mL of AMV was placed in the cuvette. The cuvette was placed inside of spectrophotometer and the amount of absorbance was recorded. This procedure that involves a solution with a known concentration was repeated for the concentrations:1.0x10-4 M,5.0x10-5 M,2.0x10-5M, and1.0x10-5M.A unknown solution absorbance was measured by putting 5 mL of unknown solution with 2.5 mL AMV in a cuvette. The cuvette was placed in the spectrophotometer and the amount of absorbance was recorded. The procedure that deals with the unknown solution was repeated 2 more times with the same solution and the same amount of solution and AMV. The average of the three unknown solution was calculated and the concentration of the unknown solution was
The story of the penny starts on 1792 it came with several different coins including the dime, nickel, quarter, and half penny. The pennies were first made out of 100% copper but the price of the copper went up, because of inflation the power of the penny went down. The cause of the mint to reduce the amount of copper in pennies first from 100% to 95% but then to 5% copper and 95% zinc. Despite the debate in 2006 the value of metal on older pennies rose over one. They became more dead than alive so people began to melt and sell.
Jim Kolbe, an Arizona Republican, has tried multiple times to propose, and pass legislation that would not ban, but “discourage” the use of pennies by rounding price’s up or down to help dull down our need of pennies. When we dig deeper into the facts, we find Kolbe might just be trying to get his state more money, as the penny is 97.5% zinc, and
Nickel is one of the most important elements on the periodic table. It has plenty of history, as well as a huge importance to society. Its has unique chemical, physical, and geological properties. Nickel is used commercially in abundance, as it is used anywhere from simple art products such as ceramics to complex structures such as tubing for desalination plants. It is even used in the American five-cent coin, the "nickel".Nickel was discovered by Axel Fredrik Cronstedt, in Sweden, during the year 1751.
The penny is widely loved in the community, the penny is useful in some situations, but can be a pain in others. The penny is worth 1¢, the penny is made up of Zinc, it costs exactly 1.66¢ to manufacture 1 penny. This is already reason enough to stop the penny from being produced, except for the fact
of Copper Sulphate. To do this I plan to work out the amount of water
The data from the chromatography portion of the experiment showed that the least polar of the pigments would travel the most and the most polar would travel the least; chlorophyll b was the most polar and carotene was the least polar. The spectrophotometric portion of our experiment support this as well by showing us what wavelengths the pigments reflected and absorbed. With any experiment, however, are there sources of error. One source of error with this experiment would include not cleaning the cuvettes before placing them in the spectrophotometer. The smallest fingerprints or particles can lead to an inaccurate transmittance reading. Also, not using the reference cuvette when changing wavelengths is a source of error because it will lead to an inaccurate reading. Sources of error when using the chromatography paper include, too much or too little time for the solvent to ascend up the paper and the possibility that the solvent level may be too high. When studying photosynthetic wavelengths and pigments, it is known that, depending on the plant, some pigments are absorbed during photosynthesis while others are not. Pigments absorb only the light energy that is necessary in carrying out photosynthesis. This knowledge can assist in determining what areas
The Electrolysis of Copper Sulphate Aim Analyse and evaluate the quantity of Copper (Cu) metal deposited during the electrolysis of Copper Sulphate solution (CuSo4) using Copper electrodes, when certain variables were changed. Results Voltage across Concentration of solution electrode 0.5M 1.0M 2.0M 2 5.0 10.6 19.5 4 10.5 19.8 40.3 6 14.3 26.0 60.2 8 15.2 40.4 80.3 10 15.0 40.2 99.6 12 15.1 40.0 117.0 Analysing/Conclusion The input variables in this experiment are; concentration of the solution and the voltage across the electrodes. The outcome is the amount of copper gained (measured in grams) at the electrodes. By analyzing the graph, we can see the rapid increase of weight gained for the 2.0 molar concentration as the gradient is steeper.
The nickel, originally issued in 1866, and the penny, originally issued in 1793, both were made with the intent to be used regularly as a significant value of currency. However with inflation, their utility in the economy is decreasing, and now is no longer practical to use as a denomination of currency. Both the nickel and the penny share much of the same issues. The 2015 cost of minting a penny is approximately 1.7 cents, while the cost of minting a nickel is approximately 9 cents, so the government effectively loses money each time these coins are manufactured. These costs are due to the cost of the raw metals used as well as overhead costs and manufacturing costs.
Spectroscopy Spectroscopy is the study of energy levels in atoms or molecules, using absorbed or emitted electromagnetic radiation. There are many categories of spectroscopy eg. Atomic and infrared spectroscopy, which have numerous uses and are essential in the world of science. When investigating spectroscopy four parameters have to be considered; spectral range, spectral bandwidth, spectral sampling and signal-to-noise ratio, as they describe the capability of a spectrometer. In the world of spectroscopy there are many employment and educational opportunities as the interest in spectroscopy and related products is increasing.
Raman spectroscopy is, besides IR spectroscopy, one of the two spectroscopic methods used for vibrational analysis. Both techniques are used to provide a fingerprint of molecules by generating spectra. The main difference is that IR spectroscopy is based on absorption of photons with a frequency equal to the vibrational frequency of functional groups, whereas Raman spectroscopy is based on inelastic scattering of monochromatic light. (14) Also different selection rules apply on these techniques, meaning the techniques are
.... I. et al., 2009. In Use Stock of Copper Analysis Using Satellite Nighttime Light observation Data. Materials Transactions , 50(7), pp. 1871-1874.
In order to analyze a sample for its atomic constituents, it has to be atomized. The sample should than be illuminated by light. The light transmitted is finally measured by a detector. In order to reduce the effect of emission from the atomizer (e.g., the black body radiations) or the environment, spectrometer is normally used between the atomizer and the detector.