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Darrian Bell
September 7, 2011
Flame Tests
Introduction/Purpose:
In this experiment, I performed a flame test on seven different metallic ions using
a lab burner. Also, I performed a flame test on two unknown substances. The theory of
the experiment is that the color of an ion represents the energy level of the ion. Each
ion has a different color, although some may be similar to the same color or a different
shade of the same color. The color depends on the energy change that takes place.
Problem: What colors are characteristic of particular metallic ions in a flame test?
Hypothesis: The ions will be the simple colors of the rainbow, or somewhat similar.
(Different shades.) The colors at the top of the rainbow will be the ions with least energy
and the ones at the bottom will be the ions with the highest energy.
Experiment:
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Independent Variable: metallic ions
Dependent Variable: color
Constant Variable: same flame
Control Group: no solution on the loop
Experimental Group: unknown groups
Procedures:
1. Gather materials and read the lab information.
2. Light the burner and adjust the flame to low.
3. Before each test, clean the wire. Then, dip the loop into a container and hold the
loop on the flame until a color appears. (May have to repeat if color doesn’t
appear in a few seconds.)
4. Record your results.
5. Repeat experiment on the unknown solutions.
6. Turn off the burner and clean up your area.
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Data:
Salt Solution
Ba(NO3)2
Cu(NO3)2
LiNO3
KNO3
NaCl
Ca(NO3)2
Sr(NO3)2
Color
Yellow
green
Rose red- orange
Pink- purple
Bright orange
Red orange
Hot pink
Unknown
D1
D2
Color
Pink- purple
Bright orange
Analysis:
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What metallic ions are present in the unknown solutions?
K & Na
Summarize the process that produces the colors seen in the flame tests.
Electrons are absorbing energy from the flame, and then it releases that energy
and the color or the flame charge.
What is the relationship of the colors you saw and the lines of the
electromagnetic spectrum produced by the metals?
More energy- blues and purples. Less energy- red and orange. Middle energyyellow and green
Which element gave the most easily identified color?
Cu(NO3)2
Which element was hardest to identify?
LiNO3
Do you think that flame tests are valuable for detecting metal ions present in
amixture of metal ions? Explain.
Yes, they are similar to fingerprints because no one is the same.
What are paper logs that are burned in fireplaces soaked in solutions of metal
salts? Which metals (colors) would be most desirable?
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 To see pretty colors; rose-red and orange.
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List the metal ions from least to highest energy.
LiNO3
Ca(NO3)2
NaCl
Ba(NO3)2
Cu(NO3)2
Sr(NO3)2
KNO3
Conclusion:
By concluding the experiment, the metallic ions tested in the flame test were
rated in the energy levels by the color of the flame. The results proved my hypothesis by
the data in the graphs and analysis questions recorded during and after the experiment.
The colors at the top of the rainbow were the lowest energy ions and the colors at the
bottom were the highest energy ions.