Question

Why did you blank with the 0.0020 M Fe(NO3)3 solution as opposed to just DI water? What does it do to your spectrum? What chemicals create the absorbance of the standard solution in Test Tube #4)? How can you find the absorption of only the FeNCS2+ in the standard solution?

Answer 1

Answer:

The cuvette was blank with the solution so that the spectrometer will only read the solute absorbance. This also ensures that the spectrometer will ignore other absorbance fluctuations that normally occur due to the chemical make-up of water. The spectrometer only considered the absorbance of $FeNCS^{2+}$ as indicated on the spectrum. The reaction between the $Fe^{3+}$ and the $SCN^{-}$ are both clear liquids that form the orange liquid product  $FeNCS^{2+}$ which creates the absorbance spectrum. Because the color of the solution is orange, it reflects this and similar colors while absorbing blueish hues. We can find the absorption of only the $FeNCS^{2+}$ by pre-rinsing the cuvette with each solution we intend to measure before placing it in the spectrometer. Also, wipe each cuvette with a kimwipe to remove all fingerprints that could effect the data collection.

Explanation:

The cuvette was blank with the solution so that the spectrometer will only read the solute absorbance. This also ensures that the spectrometer will ignore other absorbance fluctuations that normally occur due to the chemical make-up of water. The spectrometer only considered the absorbance of $FeNCS^{2+}$ as indicated on the spectrum.