6/20/2013

Experiment 8 The Emission Spectra of Atoms and Ions

Goal: To use a spectroscope to study emission spectra.

Procedure:

Part 1

Familiarize yourself with spectroscope.

Record the color for the Hg discharge lamp you observe. Do not look at it for more time than it takes to look for it.

Point the spectroscope at the mercury lamp and look through the eye piece. Record the positions of all line sat the end of the report to the nearest 5nm.

Part 2

Point the spectroscope at the Hydrogen discharge lamp and record the spectrum on the data sheet. Record the color of the lamp, and as many lines as you can see.

Part 3

Light the Bunsen burner to a bright blue triangle inside the larger, more diffuse flame.

Take the spectrum of a wooden splint being heated in the flame. Do this carefully. Observe the emission and record your observations on the data sheet. Record the color of the heated splint to the unaided eye.

Repeat the procedure with all of the known solutions.

Obtain your unknown solution and record it.

Take the spectrum and record it. Compare your spectrum to the known salts and identify it. Record the identity of the unknown solution.

Principle of Experiment: The Rydberg constant and spectrum emission.

Relevance of Experiment: To calibrate the instrument using a mercury lamp, record and identify the Rydberg series of the hydrogen atom, and determine the identity of an unknown ion by its emission spectrum.