Three unknown solutions were prepared by pipetting 15.00 mL of an unknown nickel solution into a 200.00 mL volumetric flask and diluting to the mark. Then three samples were prepared from this dilute unknown solution by pipetting 5.00 mL of the dilute solution into a 25.00 mL flask, to which the reagents were added then it was diluted to the mark. UV Spectroscopy analyzed the resulting solutions and the unknown absorbance value were converted to concentration by means of a calibration curve, Table 4-1. Fill in the diagram with appropriate volumes. Determine the concentration of the original nickel solution, in ppm Ni, from each of the three unknown solutions and an average. Included appropriate error calculations. Show complete calculations using Trial 1 data. Present results for all trials and the average with uncertainties.

Question

Three unknown solutions were prepared by pipetting 15.00 mL of an unknown nickel solution into a 200.00 mL volumetric flask and diluting to the mark. Then three samples were prepared from this dilute unknown solution by pipetting 5.00 mL of the dilute solution into a 25.00 mL flask, to which the reagents were added then it was diluted to the mark. UV Spectroscopy analyzed the resulting solutions and the unknown absorbance value were converted to concentration by means of a calibration curve, Table 4-1. Fill in the diagram with appropriate volumes. Determine the concentration of the original nickel solution, in ppm Ni, from each of the three unknown solutions and an average. Included appropriate error calculations. Show complete calculations using Trial 1 data. Present results for all trials and the average with uncertainties.

Answer 1

something is missing here. Data?

Answer 2

To determine the concentration of the original nickel solution in ppm Ni, we need to follow these steps:

1. Calculate the concentration of nickel in the diluted unknown solution (Volumetric flask):
- Volume of the unknown nickel solution pipetted into the volumetric flask = 15.00 mL
- Volume of the volumetric flask = 200.00 mL
- Concentration of nickel in the diluted unknown solution = (concentration of nickel in the original solution) x (volume of original solution)/(volume of diluted unknown solution)

2. Calculate the concentration of nickel in the reagent flask using the given calibration curve (Table 4-1):
- Measure the absorbance of the reagent flask using UV Spectroscopy.
- Convert the absorbance value to concentration using the calibration curve.

3. Calculate the concentration of nickel in the final sample solution (25.00 mL flask):
- Volume of the diluted unknown solution pipetted into the final sample flask = 5.00 mL
- Volume of the final sample flask = 25.00 mL
- Concentration of nickel in the final sample solution = (concentration of nickel in the diluted unknown solution) x (volume of diluted unknown solution)/(volume of final sample solution)

4. Repeat steps 2 and 3 for each of the three trials.

5. Calculate the average concentration of nickel for all three trials:
- (Concentration of nickel in trial 1 + Concentration of nickel in trial 2 + Concentration of nickel in trial 3)/3

Now, let's do the calculations using Trial 1 data as an example:
- Volume of the unknown nickel solution pipetted into the volumetric flask = 15.00 mL
- Volume of the volumetric flask = 200.00 mL

Using the given calibration curve (Table 4-1), the concentration of nickel in the diluted unknown solution is determined as follows:

- Measure the absorbance of the reagent flask using UV Spectroscopy: let's assume the absorbance value is A1.
- Convert the absorbance value to concentration using the calibration curve: refer to Table 4-1, find the corresponding concentration value for absorbance A1, let's call it C1.

Then, calculating the concentration of nickel in the final sample solution (25.00 mL flask):

- Volume of the diluted unknown solution pipetted into the final sample flask = 5.00 mL
- Volume of the final sample flask = 25.00 mL

The concentration of nickel in the final sample solution is given by:

Concentration of nickel in the final sample solution = (C1 x 15.00 mL) / (5.00 mL)

To account for uncertainties and errors, you need to use the proper formulas and apply error propagation techniques. Error calculations involve considering the uncertainties in measurements, calibration curve, and dilutions.

Repeat these calculations for Trials 2 and 3, and then calculate the average concentration of nickel using the formula provided in step 5. Remember to perform error calculations for the average concentration as well.

Please note that without access to the calibration curve (Table 4-1), I cannot provide the specific values for concentrations, uncertainties, and errors in this example. You will need to refer to the calibration curve and fill in the appropriate values in the calculations.