[Edit this paragraph] definition of the color reaction of flame
Flame color reaction of some metals or their compounds in the volatile colorless flame burning when the flame so that the color characteristics of a response.
[Edit this paragraph] the reasons for the color reaction of flame
When the alkali metal and its salts in the ignition flame, the atoms absorb the energy of the electron from the orbit of low-energy transition to a higher energy orbit, but at a higher energy orbit is unstable electronic, it is fast transition back to a lower energy orbit, then the energy will be redundant form to emit light. And emit light in the wavelength range of visible light (wavelength of 400nm ~ 760nm), and thus can show the color of flame. However, due to the structure of alkali metal atoms in different electronic transition energy when the change is not the same as on the different wavelengths of light, the color reaction from the flame in the experiment see the special flame color, the color spectrum is the spectrum. Each elements have some characteristics of the spectral lines, the issue of the characteristics of the color of flame coloring, according to some kind of flame can determine the existence of elements. If the flame color Magenta contain strontium isotopes, jade green flame containing copper, flame containing sodium, such as yellow.
[Edit this paragraph] of the experimental flame reaction
(1) experiment supplies: platinum wire (or wire), alcohol lamp (or gas), concentrated hydrochloric acid, cobalt blue glass (when tested with potassium).
(3) process: ① the platinum wire dipped in concentrated hydrochloric acid to colorless colorless flame on the ignition; ②sample (solid directly) in the colorless flame ignition, to observe the flame color (if test potassium cobalt glass through observation, because in most cases need to be used when the system of potassium sodium, potassium solution, therefore often contain sodium, and sodium yellow flame color reaction, a small amount of yellow and purple, respectively, can not come out). ③ the platinum wire and then dipped to the Colorless concentrated hydrochloric acid burn, you can continue to do a new experiment.
[Edit this paragraph] response to the application of flame
Flame test color reaction for certain trace metals or their compounds, can also be used for fireworks festival.
[Edit this paragraph] common reaction flame
Huang Na Na
Li-Li purple
K + K
Rubidium Rb Purple
Cesium Cs purple
Calcium Ca brick red
Strontium Sr magenta
Green Copper Cu
Ba Ba aureoviride
Rare gas discharge color
He pink
Ne red
Ar Purple
Xe Blue
[Edit this paragraph] flame test ion reaction
1. Sodium ions:
Sodium flame color reaction should not be difficult to do this, but the most troublesome to do. Because the sodium yellow flame color, and light the flame of alcohol lamp wicks due to unclean, impure alcohol most of the flame yellow. Even the near-colorless (On blue) flames, a new wire (or nickel wire, platinum wire) on the ignition, the beginning of the flame is yellow, it is difficult to explain is the flame of sodium ions alcohol lamp, or the original color of the flame. To clearly see the yellow sodium flame, the following methods can be used.
⑴ method a (tweezers - Cotton - Alcohol Law): take a small collegecotton (cotton wool, the same below) smoke a little alcohol (95% ethanol, the same below), the alcoholcotton with some of the James Cotton sodium chloride or anhydrous sodium carbonate powder (small study), lit.
⑵ method II (Wire Act): ① take a thin wire, one end with sand paper wipe, and then lightson alcohol to non-yellow flame ignition, ② wire with the end of the water dip, and then dip a number of sodium chloride or anhydrous sodium carbonate powder, ③ ignited a new spirit lamp (lamp wick is clean, pure ethanol), ④ the stained sodium salt powder on the wire on the ignitiontip, when there is a sharpsmall yellow flame, which is sodium flame. Experimental demonstration of the practice of teachers more than make it easier to do, but because the majority of students in the experiment do not clean the alcohol lamp flame tip and it is difficult to see, can be changed to the following: stained sodiumon the wire in any one of a blue flame parts of the ignition, yellow flame blue flame coverage, you can believe that the flame is yellow sodium flame.
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