Determining the Amount of Copper in a Penny Solution

How can we determine the amount of copper in the penny solution?

If the measured absorbance for the penny solution is 0.449, how many grams of copper were in the penny?

Answer:

To determine the amount of copper in the penny solution based on the measured absorbance of 0.449, we need to follow a series of steps using a calibration curve and known concentration values of copper ions.

In order to calculate the amount of copper in the penny solution, we first need to establish the relationship between absorbance and concentration by creating a calibration curve. This curve will help us determine the concentration of copper ions based on the absorbance value.

1. Prepare a series of standard solutions with known concentrations of copper ions and measure their absorbance values.

2. Plot the absorbance values on the y-axis and the corresponding concentrations on the x-axis to create the calibration curve.

Once we have the calibration curve, we can proceed with determining the concentration of copper ions in the penny solution using the measured absorbance value.

3. Locate the absorbance value of 0.449 on the y-axis of the calibration curve and draw a horizontal line to intersect the curve. The intersection point represents the concentration of copper ions in the penny solution.

4. Now, assuming we used 100 mL of the penny solution, we can calculate the number of moles of copper ions present in the solution using the formula: moles = concentration * volume.

5. Next, we convert the moles of copper ions to grams using the molar mass of copper, which is 63.55 g/mol. The formula for this conversion is grams = moles * molar mass.

By following these steps, we can accurately determine the amount of copper present in the penny solution based on the measured absorbance value.