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 chemic

Question

2 months ago

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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 chemic

als 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?

Chemistry

1 answer:

KiRa [2.9K] · Answer 1 · 2026-04-11T09:05:07+03:00

Response:

The cuvette was prepared with the solution so that the spectrometer measures solely the absorbance from the solute. This also means the spectrometer disregards other fluctuations in absorbance that typically arise from the composition of water. The spectrometer focused only on the absorbance of $FeNCS^{2+}$ as reflected in the spectrum. The reaction between the $Fe^{3+}$ and the $SCN^{-}$ produces two clear liquids that generate the orange product $FeNCS^{2+}$ which leads to the absorbance spectrum. Due to the orange color of the solution, it reflects this hue and others like it, while absorbing blue tones. To isolate the absorption of just the $FeNCS^{2+}$ , pre-rinsing the cuvette with the solutions intended for measurement is advisable, along with using a kimwipe to clean any fingerprints that might impact data collection.

Clarification:

The cuvette was prepared with the solution so that the spectrometer measures solely the absorbance from the solute. This also means the spectrometer disregards other fluctuations in absorbance that typically arise from the composition of water. The spectrometer focused only on the absorbance of $FeNCS^{2+}$ as reflected in the spectrum.