Chemistry Lab: Flame Test to Determine Unknown Substances
Lab: Flame Test
Purpose: to determine the ID of 2 unknown substances
Background Information:
Every atom consists of a nucleus with tiny electrons whizzing around it. The further away from the nucleus they are, the more energy the electrons have. If a metal atom is heated, the electrons get enough energy to jump higher away from the nucleus, they become “excited”. When they fall back closer to the nucleus (back to their ground state), they give off this extra energy as light.
Why is the flame test handy? It’s handy because we can use the colors emitted by atoms to tell different elements apart. Can we tell every element apart from this test? Not with our flame test, but the idea of spectroscopy allows us to do so with a good detector and knowledge of spectral lines. Each metal will have it’s own unique spectral lines that correspond to the distances between electron orbits.
Water samples are tested for heavy metals and other contaminants using spectroscopy. Elemental compositions of stars and planetary atmospheres can be determined by the emission lines given off. Hair, blood, and urine samples can be tested to see if you’re being poisoned by “heavy metals”. The list of things that spectroscopy is used for is huge.
Different metals (atoms) produce different colored light. If we look at the color of the light made when a metal compound is heated in a flame, we can tell which metal is in the compound.
Hypothesis: If metal compounds are heated & the colors are recorded, then the data can be used to determine the identity of an unknown metal.
Materials: forceps/tweasers goggles & apron
Bunsen burner electric match spectroscope wooden splints
Procedure:
1. Adjust Bunsen burner flame so it is completely blue & about 3 inches high.
2. Take 1 splint from the container& get a few grains of the compound in the vial on it. Make sure you note which substance you get on the splint. (Label a paper towel with the name of the chemical &
Purpose: to determine the ID of 2 unknown substances
Background Information:
Every atom consists of a nucleus with tiny electrons whizzing around it. The further away from the nucleus they are, the more energy the electrons have. If a metal atom is heated, the electrons get enough energy to jump higher away from the nucleus, they become “excited”. When they fall back closer to the nucleus (back to their ground state), they give off this extra energy as light.
Why is the flame test handy? It’s handy because we can use the colors emitted by atoms to tell different elements apart. Can we tell every element apart from this test? Not with our flame test, but the idea of spectroscopy allows us to do so with a good detector and knowledge of spectral lines. Each metal will have it’s own unique spectral lines that correspond to the distances between electron orbits.
Water samples are tested for heavy metals and other contaminants using spectroscopy. Elemental compositions of stars and planetary atmospheres can be determined by the emission lines given off. Hair, blood, and urine samples can be tested to see if you’re being poisoned by “heavy metals”. The list of things that spectroscopy is used for is huge.
Different metals (atoms) produce different colored light. If we look at the color of the light made when a metal compound is heated in a flame, we can tell which metal is in the compound.
Hypothesis: If metal compounds are heated & the colors are recorded, then the data can be used to determine the identity of an unknown metal.
Materials: forceps/tweasers goggles & apron
Bunsen burner electric match spectroscope wooden splints
Procedure:
1. Adjust Bunsen burner flame so it is completely blue & about 3 inches high.
2. Take 1 splint from the container& get a few grains of the compound in the vial on it. Make sure you note which substance you get on the splint. (Label a paper towel with the name of the chemical &