Analysis Of Brass

Brass is a generic term for alloys that contain copper and zinc (Lab Packet). An alloy is a metal that consists of a mixture of metals. They can have varying amounts of zinc and other elements composed within the alloy such as iron, lead, aluminum, and tin (Lab Packet). These variations in the components of brass produce a wide range of brass properties but all brass is corrosion resistant. This ideal alloy has many purposes ranging from musical instruments to architectural purposes such as pipes (Terence). Using visible spectroscopy provides a method for finding the percent copper in brass. Spectroscopy involves the interaction between light and matter. The absorbance has a linear relationship between the concentration of a substance. By using

No modification were made to this procedure as outlined in lab packets pages 17-18. The purpose of this advanced inquiry was to analyze the amount of copper in a brass sample using visible spectra. The percent copper in brass calculated was 84.2%. Finding the percent of copper was found by creating a calibration curve of various copper (II) nitrate solutions. This was used to create a possible range of copper ions when dissolving copper with nitric acid extending from 0.05 M to 0.4 M (Lab Packet). 10 mL samples of 0.05M, 0.1M, 0.2M, and 0.4M were created for the calibration curve. The ratio between Copper(II)Nitrate and H2O were found by using the following formula: M1V1=M2V2. This equation is utilized for dilutions and was used to find the volume of water and Copper(II)Nitrate. These solutions were then placed into the spectrometer to measure their absorbance of orange light (610nm). The 0.05 M solution had an absorbance of 0.063. The 0.1 M solution had an absorbance of 0.144 and the 0.2 M had an absorbance of 0.302. The last solution with a 0.4 M had a 0.598 absorbance. These data points created a line of best fit that showed the linear relationship between absorbance and concentration. The equation yielded was

Applying Beer’s Law the concentration of this solution was derived using the absorbance (y) to solve for the concentration (x). This was done by using the line of best derived from the Copper(II) Nitrate solutions. The concentration of the copper dissolved in nitric acid was .125M. The number of copper ions were calculated in grams by using the molarity and the balanced equation . Dividing the number of grams of copper to the total mass of the copper pellets yielded a 84.2% copper in brass. No major sources of errors occurred during the lab. The r2value was equal to 1 that suggest a very strong correlation with the variables. Further this value depicts the line of best fit worked well with the given data points and was extremely accurate. Overall, spectrophotometry is the study of light and matter (Kevin Vo). A spectrometer can find the concentration of a substance if the absorbance is known. In this lab, these concepts were applied to find the percent mass of copper in a brass