The United States nickel contains about 25% nickel metal and 75% copper metal. Could you use...
The United States nickel contains about 25% nickel metal and 75% copper metal. Could you use the same experimental procedure to determine the percentage of copper metal in a nickel coin that you used for a penny? Why or why not? Describe any modifications to the procedure that would be required. Hint: think about the reactions involved and the complex ions that would be formed.
Here's kind of a summary of the procedure if it helps in
answering this question:
The goal of this lab was to determine the amount of copper in a
penny using visible spectroscopy. In order to do this, there were
two things we had to do. The first was dissolving a penny in nitric
acid determine the amount of copper in it. The second part was
preparing standards solutions of Cu2+ and determine the
wavelength of maximum absorbance. In order to prepare the
standards, we obtained 0.8910 grams of Cu2+ and then
used deionized water to dilute the solution to 100mL. Then we used
stock solution to create standards of 2.00mL, 4.00mL, 6.00mL, and
8.00mL Cu2+. 2.00mL of NH3 was added to each
of the standards to make the copper turn blue and then the
wavelength and absorbance were measured based on the maximum
wavelength of standard 2, 4.00mL.10mL of the penny solution was
placed in three 25mL volumetric flasks, 2.00mL was added and then
they were diluted to 25mL. Using the maximum wavelength, we
measured the absorbance for each of the three samples and
calculated the concentration of copper in each of them. The
concentration was then used to calculate the amount, in grams, of
copper.
Homework Answers
The same method cant be used to calculate the percentage of Copper in Nickel. Because when you dissolve the metal in concentrated nitric acid, both the metals will dissolve and form colored complexes.
When you use the UV- Visible spectrometer to measure the absorbances, the absorbance will be due to both Cu and Ni complexes present. hence the same method can not be used to calculate the % of Copper only.
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The United States nickel contains about 25% nickel metal and 75%
copper metal. Could you use...
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Here's what I think I have to do:
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b is 1.66 cm. I think c is .400 M NiSO4, but I'm not sure. I
also think Abs is 0.758 given the graph. (If wavelength is 380 nm,
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To determine the solubility product of copper(II) carbonate,
CuCO3 , a concentration cell as described on pages 71-72
of the lab handout is constructed. The temperature of the Galvanic
cell is measured to be 22.5°C, and the cell potential 282 mV (0.282
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