Flame Tests, Atomic Spectra and Applications Activity
(See teacher background information in Flame Tests, Atomic Spectra and Applications Activity)
Introduction:
Have you ever seen a fireworks display? Where do all of the colors come from?
Below are some links to the chemistry of fireworks:
http://chemistry.about.com/od/fireworkspyrotechnics/Fireworks_Pyrotechnics.htm
http://alchemy.chem.uwm.edu/amalgamator/NCW/ncw2001/fireworks.html
In this activity, you will investigate the colors of flame produced by solutions of metal salts.
A flame test is a procedure used to test qualitatively for the presence of certain metals in chemical compounds. When the compound to be studied is excited by heating it in a flame, the metal ions will begin to emit light. Based on the emission spectrum of the element, the compound will turn the flame a characteristic color. This technique of using certain chemical compounds to color flames is widely used in pyrotechnics to produce the range of colors seen in a firework display.
Certain metal ions will turn the flame very distinctive colors; these colors in turn can help identify the presence of a particular metal in a compound. However, some colors are produced by several different metals, making it hard to determine the exact ion or concentration of the ion in the compound. Some colors are very weak and are easily overpowered by stronger colors. For instance, the presence of a potassium ion in a compound will color a flame violet. But on the other hand, even trace amounts of sodium ions in a compound produce a very strong yellow flame, often times making the potassium ion very difficult to detect. To counteract the effects of any sodium impurities, one can view the flame through a piece of cobalt blue glass. The cobalt glass absorbs the yellow light given off by sodium while letting most other wavelengths of light pass through.
In this activity, wooden splints dipped in solutions of metal salts are heated using a Bunsen burner,
Introduction:
Have you ever seen a fireworks display? Where do all of the colors come from?
Below are some links to the chemistry of fireworks:
http://chemistry.about.com/od/fireworkspyrotechnics/Fireworks_Pyrotechnics.htm
http://alchemy.chem.uwm.edu/amalgamator/NCW/ncw2001/fireworks.html
In this activity, you will investigate the colors of flame produced by solutions of metal salts.
A flame test is a procedure used to test qualitatively for the presence of certain metals in chemical compounds. When the compound to be studied is excited by heating it in a flame, the metal ions will begin to emit light. Based on the emission spectrum of the element, the compound will turn the flame a characteristic color. This technique of using certain chemical compounds to color flames is widely used in pyrotechnics to produce the range of colors seen in a firework display.
Certain metal ions will turn the flame very distinctive colors; these colors in turn can help identify the presence of a particular metal in a compound. However, some colors are produced by several different metals, making it hard to determine the exact ion or concentration of the ion in the compound. Some colors are very weak and are easily overpowered by stronger colors. For instance, the presence of a potassium ion in a compound will color a flame violet. But on the other hand, even trace amounts of sodium ions in a compound produce a very strong yellow flame, often times making the potassium ion very difficult to detect. To counteract the effects of any sodium impurities, one can view the flame through a piece of cobalt blue glass. The cobalt glass absorbs the yellow light given off by sodium while letting most other wavelengths of light pass through.
In this activity, wooden splints dipped in solutions of metal salts are heated using a Bunsen burner,