2007-03-09 04:57:17 · 9 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
In the lab, the best way to prove that a chemical reaction has occured is with chromatography. Thin Layer Chromatography (TLC) is the most convenient and it takes only a few minutes. In fact, one can easily follow the course of a reaction with TLC: spots will disappear on one place on the plate, and reappear elsewhere. This proves chemical transformations. Other wet chemical or spectroscopic techniques can prove it, as well, as previously noted.
Color change does not prove chemical reaction. Anyone who mixes paint knows this.
Temperature change does not prove chemical reaction. Some solutes give off heat when dissolved and others get cold (examples: NaOH or urea in water)
Evolution of gas does not prove reaction. Gases may already be dissolved or trapped physically.
Precipitation from solution does not prove reaction; the common ion effect or relief of supersaturation may be taking place.
2007-03-09 07:09:38 · answer #1 · answered by Glenguin 7 · 0⤊ 0⤋
Color changes, gas production, change of state (ie liquid to solid) all indicate a chemical reaction has occured.
If you want proof beyond a reasonable doubt, run the propoes reaction, and then test the final product using a combination of mass spectrometry and NMR. If the final product has a different molecular structure than the reactants put into the pot, you have definite proof that a reaction has occured.
In most cases, the things I listed are sufficient to say that a chemical reaction has occured.
2007-03-09 06:31:15 · answer #2 · answered by Marc G 4 · 0⤊ 0⤋
In a chemical reaction, atoms rearrange to form new substances. A chemical analysis is the only way to prove that a reaction has occurred.
2007-03-09 05:06:47 · answer #3 · answered by VirtualElvis 4 · 2⤊ 0⤋
the only to know for sure that a chemical reaction has taken place is if you started with 2 or more reactants and when they were exposed to each other they produced/yielded a new product.
for example take water
H + H + O yeilds water (H20)
2007-03-09 07:32:19 · answer #4 · answered by autumnleaves1990 2 · 0⤊ 0⤋
Test it..depending on the reactants used..USe other reagents to test for presence of elements...Notice any small change..Take the temperature...Only way??huh..tough..
try to compare melting and boiling point
2007-03-09 05:05:36 · answer #5 · answered by lUnJ@ 3 · 0⤊ 0⤋
Theoritical assumptions can never be trusted. The best way is to perform it in the lab.
2007-03-09 05:06:09 · answer #6 · answered by Anonymous · 0⤊ 2⤋
a new substance would be created
2007-03-09 05:03:48 · answer #7 · answered by wanna_be_md 3 · 1⤊ 0⤋
Look for scars... and pain.
2007-03-09 05:30:52 · answer #8 · answered by TreePerson 1 · 0⤊ 1⤋
Drink it down.
2007-03-09 04:59:59 · answer #9 · answered by Anonymous · 0⤊ 3⤋