How Does Rust Occur?

Video Transcript

"Hi. I'm Brian with ericksontutoring.blogspot.com. Today we're going to discuss how rust occurs. So rust is a common term for when iron is oxidized. So you take iron 2 which is a stable form of iron and you remove some electrons, combine it with oxygen and you get rust which is the stuff that we all know forms. It's kind of flaky. It starts to peel off. So iron, there's two irons and three oxygens for every rust particle. They're called iron (III) oxides. That's simply because iron can have two different forms depending on the number of electrons it holds. So you have rust is iron 2 O 3. Now the way that rust actually occurs is you have, you need a couple different elements. You need to have oxygen and you need to have water. So you start out with your regular iron 2. So whatever iron structure or iron alloy you have, and then the iron in the presence of water and carbon dioxide, which is in the air, starts to form some sort of acidity form. Carbonic acid or other things. The electrons get stripped away from iron 2 and they get passed down to oxygen. So we need the oxygen because it accepts the electrons. Now that the iron has been changed to iron 3, it goes through another series of chemical reactions and eventually joins up with the broken apart water molecules and you form iron oxides or rust. Once your rust forms, it doesn't really hold together like the other iron does. It starts to flake off which exposes new sites for the rust to occur and the process sort of continues on from there. You, when rusting is occurring in the presence of additional water or salts, this accelerates the rate of rust. So that's why an ocean environment things tend to rust a lot faster. So this has been a brief discussion of how rust occurs."