Copper In Brass

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Spectrophotometric Determination of Copper in Brass Chemistry 1290-022 July 12, 2015 Amal Alsadah TA: Purpose: The primary purpose of this experiment was to determine the mass percentage of copper in a commercial brass alloy spectrometrically. Another purpose of this experiment was to use the concentration of the copper to determine the percent copper in an unknown brass sample. Learning about this type of analysis was important in an everyday context because this application can be useful to a forensics investigator. As mentioned in reference number 1, the crime scene investigator (CSI) could determine the mass percent of copper in a brass shell casing and match the composition to a specific manufacturer (1). Safety Information:…show more content…
Then, it is cleaned with steel wool. The copper wire wrapped around a pencil. • About 100 ml of cold faucet water is placed into a 250 ml flask. • 50 ml of concentrated nitric acid is measured with graduated cylinder and then 20 ml of it is transferred into an 80 ml test tube. • The test tube is then placed carefully in the 250 ml flask. It was made sure that the cold water in the flask covers about 2 cm of the bottom of the test tube. • The coiled copper wire is then placed carefully in the test tube. This reaction must be performed in fume hood and students must not inhale the toxic brown gas that is produced. The remaining nitric acid is then added slowly to the test tube that is placed in the flask to dissolve the copper wire completely. • Approximately 75 ml of deionized water is poured into a 250 ml beaker. The nitric acid solution in the test tube is then transferred to this beaker. A pale blue color will be observed. • Then, the 250 ml beaker content is transferred to a 250 ml volumetric flask. Next, the deionized water is added to until the volume reaches 250 ml. • The mixture in the volumetric flask is homogenized by stoppering and inverting volumetric flask few…show more content…
Brass is an alloy that is made of copper another metals. The nitric acid was used to dissolve brass sample. As a result of dissolving brass in the acid a blue color is made. The produced blue color is a key to the copper component in brass since all other metals do not produce any colored solutions. A brown gas (NO2) is released during the reaction. The absorbance of the standard and the diluted solutions was measured and tableted. The measured absorbances and concentrations were then used to draw a calibration curve. The calibration curve is constructed by plotting absorbance versus concentration. The graph has been utilized to find the concentration of copper in a sample of brass by tracing the absorbance to the concentration axis. Finally, the mass of copper was calculated and then used to calculate the percentage mass of copper in

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