Thx for helping juz now... erm... sorry for the next question... Cuz i m not gd in science... but math... i m good at it... thx for helping again.. :)
2007-07-28 22:48:26 · 4 answers · asked by Anonymous in Science & Mathematics ➔ Chemistry
Rust is the oxide that is formed by open-air oxidation of iron. The chemical composition of rust is mainly hydrated iron(III) oxide (Fe2O3.nH2O), and under wet conditions may include iron(III) oxide-hydroxide (FeO(OH)). Rusting is the common term for corrosion of iron and its alloys, such as steel. Although oxidation of other metals is equivalent, these oxides are not commonly called rust.
As rust has higher volume than the originating mass of iron, its buildup may force apart adjacent parts - a phenomenon known as rust smacking.
The rusting of iron is one of the more widely used examples of corrosion. This electrochemical process requires the presence of water, oxygen and an electrolyte and leads to the formation of hydrated iron oxides.
Pure, solid iron oxidizes in water:
Fe(s) -> Fe2+(aq) + 2e-
These electrons will quickly react with the disassociated hydrogen ions (in H3O+(aq) form) and the dissolved oxygen in the water (O2(aq)):
4e-(aq) + 4H3O+(aq) + O2(aq) -> 6H2O(l)
Therefore, as seen from the above equation, the more acidic the water, the greater will be the rate of corrosion (since the concentration of H3O+(aq) will be greater.) At extremely low pH’s, the hydrogen ions will react with the electrons producing hydrogen gas instead:
2H+(aq) + 2e-(aq) -> H2(g)...
2007-07-28 22:58:23 · answer #1 · answered by Anonymous · 1⤊ 0⤋
This id the same answer I gave to the question of why oxygen rusts metal:
Oxygen alone does not rust metal. The oxygen in dry air will react and form a thin film of oxide on the surface of the metal, which actually protects it from further corrosion. But when oxygen is combined with water (water or water vapour in the atmosphere) it forms iron hydroxide, which is rust, and which will continue to form and corrode the metal, as long as both oxygen and water are available.
Doctor's answer is much more detailed.
2007-07-28 23:05:08 · answer #2 · answered by AndrewG 7 · 0⤊ 0⤋
Um well I'm not sure EXACTLY how it works but i know that it's the oxygen in the water (H2O) that oxydises iron and that makes rust... Hope that answers your question ^^...
2007-07-28 23:16:37 · answer #3 · answered by Tarí 1 · 0⤊ 0⤋
water doesnt oxidize iron. but can be a source of corrosion promoting it.
2007-07-28 22:53:34 · answer #4 · answered by Alex 6 · 0⤊ 0⤋