Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
THEORETICAL AND EXPERIMENTAL TREATMENT OF DYE MOLECULES Introduction Chem Connections When polychromatic light shines on atoms and molecules only certain frequencies of light are absorbed. When an atom or molecule absorbs light, the electrons are excited to a higher energy state. Given that only certain frequencies (or wavelengths) are absorbed, we can conclude that the electrons bound to atoms are quantized. This means that only a few energy transitions for the electron exist rather than an infinite number. A good overview of greater details of the theory related to this experiment is given in the previous experiment, Exp. 8 Molecules and Light and the introduction to the experiment should be reviewed. In this experiment you will explore the light absorbing properties of molecules using several different methods. Initially you will predict the wavelengths of light absorbed just by visual inspection of the samples. Next you will calculate the expected wavelengths absorbed based on a quantum mechanical model of electrons. Finally, you will measure the actual absorbance spectra of the molecules to see how well your predictions match experimental observations. Experiment 9
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Investigation I. Predicting the wavelengths absorbed The structures of the 6 dyes used in this lab are given below: Table 1: Structures of Dyes 1,4-diphenyl-1,3- butadiene 1,6-diphenyl-1,3,5- hexatriene 1,8-diphenyl-1,3,5,7- octatetraene 1,1’-diethyl-2,2’-cyanine iodide 1,1’-diethyl-2,2’- carbocyanine iodide 1,1’-diethyl-2,2’-dicarbocyanine iodide 1) Consider the 6 solutions of dyes in lab. Predict the color of light absorbed for each based on visual inspection. Table 2: Predicted Absorption Maximum Set Dye Molecule Predicted Color Absorbed 1,4-diphenyl-1,3-butadiene 1,6-diphenyl-1,3,5-hexatriene 1 1,8-diphenyl-1,3,5,7-octatetraene 1,1’-diethyl-2,2’-cyanine iodide 1,1’-diethyl-2,2’-carbocyanine iodide 2 1,1’-diethyl-2,2’-dicarbocyanine iodide I- I- Violet Indigo Blue Green Yellow Orange Red
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

Page1 / 6


This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online