desperate assistance!!! (1 Viewer)

[wrxsti]

ive got 2 questions:

1. how do you calculate the oxidation state? (if you can, give examples)

2. for people doing option-shipwrecks...man whats the offical rust equation...there is soo many of them and very source has a different equation, if they just simply asked whats the equation for rust(overall or whatever), what would u put...

also if they asked provide the step by step process of rust(corrosion), including equations?....

much help will be apperciated
thanks in advanced

 

[Naylyn]

When you say calculate the oxidation state what exactly do you mean?

Loss of an electron increaces the oxidation state gain of an electron reduces the oxidation state.

For the rust equation I will be using the overall equation:
4Fe(OH)2 + O2 ---> 2(Fe2O3.H2O) +2H2O or
4Fe(OH)2 + O2 ---> 2(Fe2O3.xH2O) +(4 - 2x)H2O
since they are the same except the top one is simplified, these equations came from conquering chemistry 3rd edition.

At some spots on the iron surface known as anodic site iron is oxidised:
Fe ---> Fe^(2+) + e^(-1)

The electrons released then flow to other site on the surface known as cathodic sites, cathodic sites are usually those that contain some sort of impurity such as carbon, at these site the electrons oxygen dissolved in the thin film of moisture on the irons surface or in the water touching the irons surface if the object is completely submerged;

O2 + 2H2O + 4e^(-1) --> 4OH^(-1)

The iron and hydroxide ions then react to from iron hydroxide
Fe^(+2) + 2OH^(-1) --> Fe(OH)2(s)

The Iron hydroxide then reacts to form rust according to the above equation.