Purpose: Observe the colors that are being produced by certain metallic ions when vaporized in a flame.
Procedure: Collect needed supplies from Ms. Lyman such as googles, lab coats, metallic ions, methanol, matches, and glass watch. Add 3 drops of methanol to metallic ions. Then use a lit match and add to methanol. Watch as the flame moves and possibly, changes colors. As the flame burns out, record your data. continue on to the next metallic ion as the first one cools down. Once finished with the same procedure on the next metallic ion, wash previous one with water and dish soap. Continue to repeat process until all metallic ions are experimented with.
Pre-Lab Questions:
Q: What is making the color in a flame test? A: Metal Ions and the amount of energy being released.
Q: What color of light is the lowest in energy? A: Red
Q: What color of light is the highest in energy? A: Violet
Q: What color of light is the lowest in frequency? A: Red
Q: What color of light is the highest in frequency? A: Violet
Q: In chemistry, what is salt? A: Crystal
Q: How are electrons "excited"? A: They gain energy from heat/ light, putting them in an excited state.
Q: What is a ground state? A: Low energy level in electrons.
Q: How can an electron absorb energy and re-emit it as light? Why do different elements have different spectra? A: Electrons absorb photons and gain energy.
Observations and Data
Lithium Chloride LiCl
Before fire: Lumpy, white sand. During fire: Bubbled. Flame was blue, then blue and red, then red. After fire: Swirl of bubbly, white foam/liquid.
Calcium Chloride CaCl2
Before fire: Clumpy, powdered sugar. During fire: Bubbled. Flame was blue and yellow. After fire: Cloudy, calcium chloride stayed in the same place.
Calcium Carbonate CaCO3
Before fire: Clumpy, powdered sugar. During fire: Didn't bubble. Fire was blue with hints of yellow. After fire: Cloudy, saturn-like, sorta pasty looking.
Potassium Chloride KCl
Before fire: Salt. During fire: Didn't bubble. Fire was blue with hints of yellow. After fire: Crystallized veins and spread out.
Borax Na2B4O7 ⋅ 10H2O
Before fire: Powdery salt. During fire: Made tiny mounds and crackling sound. Fire was green with hints of orange. After fire: Melted plastic. Borax looked crystallized.
Copper (II) Sulfate CuSO4
Before fire: Blue fun-dip. Fine powder. During fire: Fire was blue with hints of green. After fire: A layer of white on top. Crystallized.
Unknown (Similar to potassium)
Before fire: Salt that sticks to glass, almost like static. During fire: Fire was blue, orange, yellow, and green. After fire: Crystallized and spread out.
Conclusion: I believe that Arianna and I succeeded as partners and in working through the experiment, sharing some of the roles. We were also able to make an educated guess at what the Unknown metallic ion was.
Error Analysis: I don't believe there was anything we did wrong. We got some pretty awesome results from the different metallic ions.
Post-Lab Questions:
Why is it important to test the flame color of the methanol without any compounds dissolved in it? To ensure the flame color doesn’t affect the compounds’ colors.
List the colors observed in this lab from highest energy to lowest energy. Lavender, green, orange, magenta, or magenta, lavender, green, orange.
List the colors observed in this lab from highest frequency to lowest frequency. Lavender, green, orange, magenta, or magenta, lavender, green, orange.
List the colors observed in this lab from shortest wavelength to longest wavelength. Lavender, green, orange, magenta, or magenta, lavender, green, orange.
What is the relationship between energy, frequency, and wavelength? Energy is proportional to frequency, which is inversely proportional to wavelength.
Based on the results of your experiments, what metal was found in your unknowns? Explain. The mystery metallic ion was Potassium since it seemed the most similar.
Do you think we can use the flame test to determine the identity of unknowns in a mixture? Why or why not? Based on thetest, I think the flame test is a useful. I think the flames had calcium or chlorine in them, but I'm not sure which caused the color. I'm not sure if there is any specific way for us to know what the unknown metallic ion could be, unless we asked Ms. Lyman herself. I asked some of my peers and some of them though the unknown metallic ion from our test was Borax. So there could be a couple or a few possibilities.
Why do different chemicals emit different colors of light? It depends on the amount and arrangement of electrons in their orbitals.
Why do you think the chemicals have to be heated in the flame first before the colored light is emitted? Because the electrons need to be excited, there needs to be energy put in for there to be energy coming out. Energy is needed in order for the electrons to be excited.
Most salts contain a metal and a non-metal. Look at the compounds we tested and explain how we can be sure that it is the metal atoms that are responsible for the colors that you see. Based on the data from the test, I cannot conclude that the metals caused the change in color. Since they seemed to be an exception it could be some other chemical or variable that could change the results of our test.
Colorful light emissions are applicable to everyday life. Where else have you observed colorful light emissions? Are these light emission applications related? Explain. Neon lights use different combinations of gases, which produce different colors when a current is applied. They are related because light is produced from excited electrons.
Can you think of a way in which to use the flame test? Please describe below. Maybe if you wanted to experiment with flames, metallic ions, and methanol the flame test would seem like the most obvious way. I cannot think of another way in which to use the flame test.