Flame Tests Lab Quiz
In your own words, write a short explanation on how an electron absorbs energy and re-emits it as light and why different elements have different spectra.
The electron absorbs the energy in this case it would be the heat and it re-emits by shooting a photon out to lose their energy when the element is dying.
how many metallic ions & nitrates will you be observing?
2 unknowns & 10 ionic compounds
Under what circumstances do atoms give off light? Why do atoms of different elements give off different colors of light?
Atoms emit light when they get excited, then turn to a ground state and emit certain photons. The color of light emitted depends on the energy emitted by each electron returning to the original state.
Why do different chemicals emit different colors of light?
Because all the chemicals have different amounts of energy, frequency, wavelength
What effect do chloride compounds have on the colors observed in flame test?
Chloride compounds produce no color, so the true colors of the metals being tested can easily be seen.
If you test 2 solutions and find that they both produce a red flame, how can you determine for sure whether they contain the same metal?
Different elements have different spacing between their ground state and higher energy state. This gives a way to identify elements by their spectrum.
What is a flame test? What does it show? How is it done?
Flame tests are used to identify the presence of a realatively small number of metal ions. You dip a metal wire into a solution and put it over the hottest part of the flame. This will give off a color showing what elements are present in the compound.
Based on the results of your experiments, what metal was found in your unknowns? Explain.
I think Copper and Lithium was in the unknown. I think this because I saw that the flame was green, yellow, red , and blue. Yellow and blue could account for the color of the flame. If we eliminate those colors, we have green and red. The green could be accounted for by the chemical Copper Nitrate (Cu(NO3)2 and the red can be accounted for by the Lithium Chloride (LiCl).
Why do you think the chemicals have to be heated in the flame first before the colored light is emitted?
I think the chemicals have to be heated in the flame first because the chemicals need to have a reaction to have a colored light.
List the colors observed in this lab from highest energy to lowest energy, highest frequency to lowest frequency, shortest wavelength to longest wavelength
Violet, Indigo, Blue, Green, Yellow, Orange, Red.
what ion determines the color of the flame
cation -compounds with matching cations produce the same color flame, anions don't -wavelength of emitted photon are in visible spectrum which are cation (alkali metals, some transition metals)
What color are potassium ions in a flame?
violet
What color are sodium ions in a flame?
yellow
