Flame Test Lab Write-Up

Sydney Schell October 18th, 2012 Identifying Metallic Components Introduction: Spectroscopy is the study of the electromagnetic radiation emitted or absorbed by the atoms and molecules. A photon in short is light. Atoms produce light by putting energy in, the electron then becomes excited and goes up an energy level, the electron then falls back down to its ground state, and out comes a photon (light). The electromagnetic spectrum contains color that we can and cannot see.
The color blue has the highest energy with shorter wavelengths and a higher frequency while the color red has the lowest amount of energy with long wavelengths and a shorter frequency. Hypothesis: If you observe the characteristic emission spectra of several gases and metallic ions then you can identify the metallic component(s) of an unknown substance based on flame color. Materials: * Samples of the following metallic salts * Calcium chloride * Copper chloride * Iron chloride * Lithium chloride * Potassium chloride * Sodium chloride * Strontium chloride * Unknown 1 * Unknown 2 Bunsen burner and accessories * Safety goggles * Lab apron * Splints soaked overnight in distilled water * 250 mL beaker half full of distilled water Procedures: 1. Place the end of one of the popsicle sticks soaked in a solution into the flame. Note color(s) of the flame and the duration of each color. Immerse the wooden splint in the distilled water to fully extinguish it, and then discard it in the trash. Record your results. 2. Repeat step 4 for each of the remaining salts. 3. Repeat step 4 for each of the unknown metals and predict the identity of the unknown metals.
Repeat any of the known metals to help with this prediction. **Wash hands thoroughly before leaving the lab. ** Some of the salts used are poisonous or irritating to the skin. Keep your hands away from your mouth until after you have washed them and have let the laboratory. Results/Data Collection/Analysis: The calcium chloride had a pretty average wavelength and turned the fire green. For some reason CuCl and NaCl both burned orange, coming in with the second lowest energy. Iron chloride had a “sparky” appearance that lasted for approximately six seconds and it was concluded that it had a high energy.

Lithium chloride burned a pinkish color. Potassium chloride had a high energy and produced a purple flame. Strontium chloride had the lowest energy which was determined by red color of its flame. Unknown 1 was strontium chloride and unknown 2 was calcium chloride. The unknowns were found by comparing their flame colors to the known substances. Formula| Metal| Color Observed| Duration(sec)| CaCl2 | Calcium Chloride| Green| N/A| CuCl| Copper Chloride| Orange| N/A| FeCl3| Iron Chloride| Sparkle| 6 sec| LiCl| Lithium Chloride| Pink| N/A| KCl| Potassium Chloride| Purple| N/A| NaCl| Sodium Chloride| Orange| 30 sec|
SrCl2| Strontium Chloride| Red| N/A| Unknown 1| Strontium Chloride| Red| 8 sec| Unknown 2| Calcium Chloride| Green| N/A| Questions: 1. What was (were) the identity of the metal ion(s) in the unknown solutions? Give evidence. -Unknown 1 proved to be strontium chloride because they shared the same flame color. Unknown 2 turned out to have a green flame which matched it up with calcium chloride. 2. Predict the flame color if metallic ions of copper and strontium were mixed. -Strontium and copper together should make a red orange or orange red depending on what the dominate color is. 3.
Based on the flame colors in the experiment, which single element would most likely be used to produce yellow fireworks? Why? -Iron would most likely be used to make yellow fireworks based on the sparks it has originally have a tannish/yellow color to them. 4. Why do the metals give off light? -When the metals are rammed into heat they react and produce light. 5. Which of the flames that you observed gave off the most energy? -Potassium chloride gave off the most energy and one could tell based on its purple flame. 6. Why do some of the samples give off more than one color flame? When an electron goes through its excited sate it changes color but when it falls back down to its ground state then it goes back to its original color. Conclusion/Discussion: The hypothesis was supported because once I found out the color flame produced by all the solutions; I could match the unknowns with the known substances. We worked to slowly when we did the lab so we had to use second hand data. Also, lighting the Bunsen burner on fire was not the best idea. Why are the flames of no two gases exactly the same color? -Different gasses have a different amount of electrons on different energy levels.