Atomic Spectra Write-up
Informal Write-up
1.
Title Page with
name, experiment title, grading rubric and date.
2.
Objective –
State the purpose of the experiment.
3.
Procedure -
reference the procedure you used. (Remember to do this both in the lab book and
the write-up.) Include note on
special safety precautions (remember the special safety glasses! Were you careful not to remove bulbs
while the power was turned on??)
4.
Introduction
– Include the basis for the experiment, any equations you will use and
their meaning, etc.
5.
Results, Calculations,
and Graphs – Your original data showing wavelengths observed should be
in the lab book only. You do
not need to recopy all of this data for the formal portion of the report. You should however make a table of the
data you used to determine the Rydberg constant (use
UV and visible literature values and experimental visible values)
Graphs needed
- 1/l vs 1/ni2 for the UV lines of
Hydrogen (121.6 nm, 102.6 nm,
97.3 nm, 95.0 nm, 93.8 nm)
- 1/l vs 1/ni2 for the visible lines
of Hydrogen you saw in lab
- 1/l vs 1/ni2 for the visible lines
of Hydrogen from literature (656.3nm, 486.1nm, 434.1nm, 410.2nm)
Use
Vernier graph to create these graphs. Vernier can
be found by clicking on the chemistry folder on the desktop of the
computers. Then click on 141 and
you will see an icon for vernier graph. Copies of the program may also be
purchased from the chemistry department for $2.00.
á
Be sure that you
have labeled all axes on the graphs (include proper units where
appropriate). Also be sure to have
a title describing the data plotted.
(Should be in the form of y vs x)
Calculated results needed
á
Calculations for determining
Rydberg constant and nf derived from the literature values of
the UV and visible spectra of hydrogen as well as your experimental data.
6.
Discussion - Discuss
any factors which may have led to poor data. Compare your value of the Rydberg
constant to the accepted value. Calculate
% difference. . Tell what electronic transitions were
responsible for each of the spectral lines in both the ultra-violet and visible
spectra.
7.
Conclusion
– Evaluate your objective and state the major data of the experiment.
8.
Questions -
Complete the questions at the back of the lab from the bookstore. Do them on the lab sheet and append
that sheet to the back of you lab report.
Remember to append the
original data from your lab book.
As always, include safety precautions and a procedural reference to the
original experiment.
Check out the following web
sites
http://jersey.uoregon.edu/vlab/elements/Elements.html
is a site with great data on the emission spectra of the
elements. (If you click on the
experiment title it will take you there.)
Click on the element to get the spectra and click on the line to get the
wavelength.
Note that the chart allows
you to observe both emission and absorption spectra. You probably want to look at the emission spectra.
For a good explanation of the
difference between emission and absorption spectra go to http://zebu.uoregon.edu/~js/glossary/spectra.html
There is also a fun
simulation at http://phys.educ.ksu.edu/vqm/html/emission.html