Chemistry

Chemical reactions and general description that represent this processes:

A) Iron Oxidation

Iron metal reacts in moist air by oxidation to give a hydrated iron oxide. This does not protect theiron surface to further reaction since it flakes off, exposing more iron metal to oxidation.

On heating with oxygen, O2, the result is the formation of iron oxides Fe2O3 and Fe3O4.

4Fe (s) + 3O2(g) → 2Fe2O3 (s)
3Fe (s) + 2O2 (g) → Fe3O4 (s)
Reaction of iron with water

Air-free water has little effect upon iron metal. However, iron metal reacts in moist air by oxidation to give ahydrated iron oxide.

Reaction of iron with the Halogens

Iron reacts with excess of the Halogens F2, Cl2, and Br2, to form ferric, That is, Fe (III) halides.

2Fe (s) + 3F2 (g) → 2FeF3 (s) (white)2Fe (s) + 3Cl2 (g) → 2FeCl3 (s) (dark brown)
2Fe (s) + 3Br2 (l) → 2FeBr3 (s) (reddish brown)

This reaction is not very successful for iodine because of thermodynamic problems. The iron (III) is toooxidizing and the iodide is too Reducing. Between The direct reaction iron metal and iodine can be used to prepared iron (II) iodide, FeI2.

Fe (s) + I2 (s) → FeI2 (s) (gray)
Reaction of iron withacids

Iron metal dissolves in dilute sulfuric acid in the absence of oxygen to form solutions containing the aquated Fe (II) ion together with hydrogen gas, H2. In practice, the Fe (II) is presentas the complex ion [Fe (OH2) 6] 2 +.

Fe (s) + H2SO4 (aq) → Fe2 + (aq) + SO42-(aq) + H2 (g)
If oxygen is present, some of the Fe (II) oxidizes to Fe (III).

The Strongly oxidizing concentratednitric acid, HNO3, reacts on the surface of
the surface and iron.






B) Making Concrete

Concrete is one of the most common materials used in construction today and has been used inconstruction since the days of the Roman Empire. Buildings, foundations, bridges, roads, sidewalks, dams and works of art are made from concrete. Concrete is a composite material made from cement,...