Chapter 52, Problem 4Q

When making the stocks and standards for the spectroscopy analysis, a student forgets to add ethanol to the salicylic acid. How will this technique error likely affect his results? Explain your answer.

Q1. Why is it important to acquire a reference spectrum and subtract it from the sample’s spectrum?  Q2. Why are quartz cuvettes better for UV-visible absorption spectroscopy than polystyrene cuvettes, especially at lower wavelengths (UV)?  Q3. What would happen if you put too much of a compound in the cuvette during the spectral measurement? Q4. Why is it important to avoid any scratch on the cuvette?  Q5. Could you use a compact fluorescent light (CFL) bulb to perform UV-visible absorption spectroscopy? Why/why not?  Q6. Predict the maximum absorption wavelength for 2,4-heptadien-6-one using Woodward-Fieser rules.  Q7. Why are n-π* transitions generally of low intensities/low absorptions?  Q8. What photon energy and wavelength would you need to send on a compound having an energy gap (Eg) of 2.7 eV? Detail your answer with appropriate information.  Q9. Using molecular orbital theory/concept (draw the important molecular orbitals), explain the difference in absorption for the…

Analyze the IR spectrum attached and state all takeaways from the data

The absorbance of sample A is higher than the absorbance of sample B.    Therefore, sample A has (circle the correct one)   more   /   less      dissolved solute than sample B. The absorbance is (circle the correct one)   directly    /    inversely      related to the transmittance of a sample.

Why KBr used in IR spectroscopic sample preparation?  Please shortly answer at your own words. Answer should be to the point (Specific 2-3 lines).

NAME PRELAB QUESTIONS These questions should be answered before coming to lab, and included when you turn in your lab outline and data sheets. 1. The dissolved compound in a sample has an absorbance value of 0.250. How would you expect the absorbance to change if: a. The concentration of the dissolved compound is tripled? b. The concentration of the dissolved compound is halved? 2. If you have a solution of unknown concentration, describe how you could determine the approximate concentration. 0.S a.r 0.1 6.0 0.0

Why are solid forms of the sample are not suitable for Uv-visible spectroscopy and Fluorescence spectroscopy? Please shortly answer at your own words. Answer should be specific (3-4 lines).

What are advantages to using a furnace instead of a flame in atomic absorption? O higher sensitivity because the atomized sample is in the optical path longer memory effects from the previous run are not present in even the most basic version O the sample is atomized in only one heating step a smaller sample amount is required less operator skill is required to determine the proper experimental conditions

A size standard: Group of answer choices A.  Is run along with every sample on a run. B.  Is used to determine the size of unknown fragments in a sample. C.  Has an expected peak pattern that is recognized by the analysis software. D.  All of the above