German_phosphate&phytoplankton

Solutions that contain the FeSCN2+ ion are blood red (you will see this at the end of the second quarter of lab). Consider the regions of the visible spectrum in which the compound should absorb light and prepare a rough sketch of absorbance vs. wavelength for each solution. Label λ max on the graph. (Is this question asking for the graph of my data at the end)

prelab 2) please see attached

The max of aspirin (molar mass 180g/mol) in neutral solution is 225 nm and & is 650 mol-¹Lcm ¹. An absorbance of 1.80 was measured for a solution of aspirin, with a 1 cm path length. Calculate the concentration of the aspirin solution.

You measure a sample in your spectrophotometer that has an absorbance of 1.00. What is the concentration of your sample in M.

1. A solution that absorbs radiation with a λmax at 475nm is placed within a UV visible spectrophotometer. An absorbance of 0.82 is recorded. Calculate the percentage of the incident light that is being absorbed.

2. You add 10.00 ml of a 0.630 M methyl red solution to a 100.00 ml volumetric flask. You then add small volumes of sodium acetate and acetic acid solutions to adjust the pH, and then fill the 100 mL volumetric flask to the mark with deionized water. You then make a spectroscopic measurement and obtain absorbance values of 0.253 at 520 nm and 0.079 at 420 nm. What is the concentration of [HIn] in the solution. Remember to use M;V1 = M2V2 as the first step in the calculation process. Hint: see eq. 6 in the lab manual A$20, = 0.367 A520, = 0.010 A420, - 0.012 A420, = 0.275 O 4.30 x 102 O 0.430 O 4.18 x 102 O 0.418

3. Fill in the following for the correspondence between % transmittance and absorbance: 100.0 % T = 0.0 absorbance 1.00 absorbance = (0.0 % T 25.0 % T = absorbance 0.25 absorbance = % T