Line Spectra Lab

Objective

The objective of this lab is broken into two parts. The first is to recognize the principles of flame ionization and atomic spectra. The second is to observe and thus further understand the line spectra for multiple elements or molecules as well as determine the correlation between emission spectra and atomic structure.

Experimental Procedure

Procedure 1: Observation of Line Spectra by Discharge Tubes Six discharge lamps were selected – argon, carbon dioxide, helium, hydrogen, iodine, mercury, and xenon. Using the spectroscopes, the wavelengths, or the average of them, were recorded. It was important to turn on the discharge tubes for only 10 seconds or less at a time with the spectroscope only approximately one inch from the
Thus the order of color from least energetic to most energetics is purple, blue, green, yellow, orange and red. It seems that all atoms and ions emit a line spectra if there is a separation in energy levels. This speaks to the reason that different atoms have different line spectra, as the separation in energy levels from Na to Mg or Ba to Li is different due to their atomic structures.

In the second part of the lab, it was possible to identify unknown A and unknown B by comparing color of the flame, observed wavelength and thus the energy. Unknown A appears to be NaCl due to the fact that it emitted an orange color at 590nm with the same energy. They shared the same line spectra and qualities, leading to the conclusion that Unknown A was certainly NaCl. Unknown B was also determined through these three qualities, leading to the understanding that Unknown B was CaCl2 as they also shared the same line spectra and very similar flame color. Regardless of the excitation source (flame or electricity), the line spectrum would be the same, resulting in these same answers, as it is still the emittance of visible