How Much Copper Is in the Coin?
We calibrated three different molarities of copper (II) nitrate. We tested for the %Transmittance of 1M, 0. 1M, and 0. 01M and plotted the data collected on a calibration curve based on concentration and absorbance. We used nitric acid to dissolve a penny to produce another copper (II) nitrate to test its %Transmittance and plot that on the graph to discover the concentration of that substance which came out to be about . 21M. We attempted to develop a method for determining the concentration of three different diluted copper (II) ion solutions.
We also tried to determine the concentration of copper within a penny by dissolving it in nitric acid. We used a spectrometer to measure the %Transmittance of each and were able to convert it to it absorbance in order to plot it on our calibration curve. We used test tubes to contain the solution and set the spectrometers to 20, which were preset by the TA. Prepare three different beakers with one containing 0. 01M, 0. 1M, and 1M of copper (II) nitrate ( Cu(NO3)2).
Fill three different test tubes full, each having different amounts of concentrations of the copper (II) nitrate. By using the spectrometer measure the %Transmittance (%T) for each. Convert each %T into its absorbance by the equation: A(absorbance)=log(100/%T) and plot on a graph. The y-axis should be labeled A and the –axis should be labeled Concn for the concentration of molarity. Draw the best fit line through the graph. Place a penny in a beaker and carefully add HNO3 and occasionally swirl so that the penny can completely dissolve.
Once the penny is fully dissolved, fill another test tube with the newly created copper (II) nitrate and again, test for the %Titration and convert it to the A. Plot it on the graph on the best fit line and find the amount of concentration that was found within the new solution. When dissolving the penny with nitric acid make certain to perform it within the hood seeing as the gas that is created is toxic. Also be very cautious when working with nitric acid due to the fact that is s corrosive to the skin.
