Determine percent Nickel in Coin?
I've been trying for hours to figure out this problem and am unable to do so.
First, I graphed the concentration v. absorbance and found a best fit trend line. Then I can plug in the absorbance to find concentration.
What I DON'T know how to do is find the concentration of coin. I know I need it to find percent of Nickel. If you could please help me out with this, that would be greatly appreciated!
The coin has a mass of 3.2844 g. It is dissolved in 42 mL nitric acid then placed in a 500 mL volumetric flask and water added to the line. The resulting solution is greenish-blue. They then pipet 1.0 mL of the coin solution into a 100 mL volumetric flask (filling to volume) and then measure an absorbance value of 0.066 in a UV-Vis spectrometer at the appropriate wavelength.
The calibration data for the spectrometer are shown below:
Solution 1 (125 ppm Ni). Absorbance = 0.200
Solution 2 (60 ppm Ni). Absorbance = 0.094
Solution 3 (32 ppm Ni). Absorbance = 0.047
Solution 4 (15 ppm N)i. Absorbance = 0.024
Solution 5 (12 ppm Ni). Absorbance = 0.020
Solution 6 (4 ppm Ni). Absorbance = 0.006
What was the concentration of Ni in the coin (expressed as a % of the total mass)?