Observation of Different Photons When Elements Are Heated (Chem Lab)

Introduction

The bright line spectrum is the range of colorful lights that are emitted from an atom in its excited state. A “normal” atom, or an atom in its ground state, is when all of the atom’s electrons are in their proper energy level. When an atom is in its excited state, electrons jump to different energy levels making them unstable. As the electron tries to get back to its respective energy level, energy is emitted in the form of light (photons).

Every element emits a different color that can be categorized into the bright line spectrum. Different elements give off different colors when heated because they all have different chemical properties, therefore, they will react differently under high temperatures. For example, [1] strontium, lithium carbonate, and strontium carbonate are often used in fireworks to create a red color. Calcium may be used to create orange, sodium for yellow, aluminum for white, barium chloride for green, copper for blue, strontium and copper for purple, and titanium for silver.

Even though all elements give off unique colors when heated, it is impossible to identify all elements with the naked eye by doing this test because you have to know what color the element burns and sometimes the elements emit very similar colors. In this experiment, five known elements will be put under extreme heat to observe the color of the light emitted. Then, three unknown elements will be determined based upon the results of the known elements.

Materials

1. Bunsen burner
2. Matches
3. Forceps
4. Wooden toothpick
5. Sample of liquid calcium

6. Sample of liquid barium

7. Sample of liquid lithium

8. Sample of liquid sodium

9. Sample of liquid strontium 

10. Three unknown liquid samples

Procedure

1. Turn on the gas for the Bunsen burner and light it with a match.
2. Using the forceps, take a toothpick and dip it into the calcium sample. Hold it in the sample for a few seconds to make sure that the sample has soaked in.
3. Stick the toothpick into the flame from the side, still using the forceps.
4. Record the color seen
5. Repeat steps 2-4 for the rest of the samples.
6. Turn the gas off.

7. When finished, compare the results of the known elements to the unknown elements to determine what they are; they will have the same color.

Conclusion

In conclusion, the unknown elements were able to be determined because their emitted color matched those of calcium, barium, and lithium.

This method for determining different elements in a controlled experiment, however, I don’t think this method would be effective for determining any unknown element. There are many elements and they may burn unique colors but often times, they are similar. For example, while performing this experiment, it was difficult to determine if unknown element1 was calcium or sodium because they both burned an orangey type color. It is possible that the toothpicks used in this lab got contaminated because someone may have touched them with their hands.

If this is the case, then the elements may have burned a different color than they were supposed to. When performing this experiment, it was observed that the colors of the flames of each sample were different. This is because each element has a different chemical property. For the element that burned a similar color, this may be because they have similar, but different, chemical properties. This method of identifying elements in real life may be used when looking at fireworks. Fireworks are different elements set on fire; the different colors that are seen are the different elements returning to their ground state.