Prelab:
1.Using the element emission spectra below, which element is found in the mixture, based upon
the spectra of the mixture?
540 580 630 720 650 740 550 690
Hydrogen Potassium Sodium
Unknown Mixture
540 550 580 630 690 720
2. What is happening in an atom to produce the lines of the above spectra?
3. Helium was first discovered in the sun without ever going there by looking at sun’s emission
spectrum. What allowed scientist to know that this was a previously unknown element?
4. Which color of the visible light portion of the emission spectrum has the most energy?
Experiment Follow up:
1. What are the two unknown ions?
2. The electrons in what chemical produced the greatest energy change.
Explain how you can tell.
3. What causes, in reference to the electrons, the different colors for the differentchemicals?
4. For your two unknown substances, write the electron configuration (both shorthand and
longhand) for the neutral atoms. How many valenceelectrons do they have?
Use the table below to answer questions 5 – 11.
Red / Orange / Yellow-orange / Green / Blue-green / Pink-lilaclithium nitrate
LiNO3 / calcium nitrate
Ca(NO3)2 / sodium nitrate
NaNO3 / barium nitrate
Ba(NO3)2 / copper nitrate
Cu(NO3)2 / potassium nitrate
KNO3
lithium chloride
LiCl / calcium chloride
CaCl2 / sodium chloride
NaCl / barium chloride
BaCl2 / copper chloride
CuCl2 / potassium chloride
KCl
lithium sulfate
LiSO4 / calcium sulfate
CaSO4 / sodium sulfate
Na2SO4 / barium sulfate
BaSO4 / copper sulfate
CuSO4 / potassium sulfate
K2SO4
lithium
Li / calcium
Ca / sodium
Na / barium
Ba / copper wire
Cu / potassium
K
5. Predict the color of the flame for the compound sodium hydroxide, NaOH. Explain your
reasoning.
6. Imagine you were in charge of creating a red and purple fireworks display. Name two
combinations of compounds you could use.
7. Does nitrate produce a colored flame? Explain your thinking.
8. Would it matter whether you did a flame test with sodium chloride, NaCl, in solid form or
sodium chloride as an aqueous solution? Explain.
9. What flame colors would be produced by these compounds? Explain yourchoices.
a. Na2CO3 b. Ba(OH)2 c. KOHd. K2CO3e. BaO
10. If two chemical samples both produce an orange flame upon testing, it isevidence that:
A. The two samples contain identical compounds.
B. The samples both contain chloride atoms.
C. The samples both contain calcium atoms.
D. The samples both contain potassium atoms.
E. The samples contain different compounds.
11. What evidence supports the claim that chloride, Cl-, does not cause theflame to have a color?
A. Lithium chloride, LiCl, and sodium chloride, NaCl, have different colors.
B. Ammonium chloride, NH4Cl, does not cause the flame to have a color.
C. Sodium chloride, NaCl, and sodium nitrate, NaNO3, both produce flames with a
yellow-orange color.
D. All of the above.
Further Investigations:
Description of what other question(s) were raised during the experiment that could be investigated with new experiments. Also a list of possible sources of error and how the current experiment could be modified to eliminate or minimize the sources of error that occurred during the experiment. Be specific.