CAUSE AND EFFECT
Corrosion is the
destruction or degradation of metals due to a redox reaction between a metal
and various substances in the environment that produce undesirable compounds.
In ordinary language, corrosion is called kararatan. The most common example of
corrosion is iron fi gure. In corrosion events, the metal undergoes oxidation,
while oxygen (air) is reduced. The metal rust is generally an oxide or
carbonate. The chemical rust formula is Fe2O3.nH2O, a solid brown-red
substance. The iron ions (II) formed at the anode subsequently oxidized to form
iron (III) ions which then form the hydrated oxide compound, which is iron
rust. As to which part of the iron acts as anode and which part acts as a
cathode, it depends on various factors, such as impurities, or the density of
the metal.
Corrosion can also be interpreted as an attack that damages the metal because the metal reacts chemically or electrochemically with the environment. There is another definition which says that corrosion is the opposite of a metal extraction process from its mineral ore. For example, iron ore minerals in the wild are present in the form of iron oxide or iron sulphide compounds, after extracting and treating, an iron will be produced for the manufacture of steel or alloy steel. During use, the steel will react with the environment causing corrosion (back to the iron oxide compound).
Zelvy : Hi dara! I left an iron metal in my yard over a month
Dara : Really?
Zelvy : Yeah, So what will happen after those week pass?
Dara : I think the color of the iron metal will changes become red
Zelvy : Why?
Dara : It's call corrosion, corrosion occurs through a redox reaction, in which the metal undergoes oxidation, while the oxygen is reduced.
Zelvy : How did you know that?
Dara : Just reading my chemistry book
Cause : Iron metal is left open in the yard for a month
Effect : The color of iron metal changes become red
Hai , dara . why the metals changes become red ? Please explanation with chemistry reactions . thanks
BalasHapushello ayu. Because he experienced corrosion or corrosion events caused by reacting with air and water. So the color turns red. And most of the color of the cultivation is red. Anode: Fe(s) → Fe2+(aq) + 2e-
HapusKatode: O2(g) + 4H+(aq) + 4e- → 2H2O(l)
What compound make the color of metal become red in corrosion phenomenon?
BalasHapusIs a mixture of air with water reacting with the iron in a relatively long period of time.
HapusAnode: Fe(s) → Fe2+(aq) + 2e-
Katode: O2(g) + 4H+(aq) + 4e- → 2H2O(l)
What can we do to prevent corrosion?
BalasHapus1. Painting: Bridges, fences, and railings are usually painted. Paint avoids the contact of iron with air and water.
Hapus2. Oil or Grease: This method is applied to various tools and machines. Oil and grease prevents iron contact with water.
3. Wrapped With Plastic: a variety of items, such as dish rack and basket basket wrapped with plastic. Plastic can prevent the contact of iron with air and water.
4. Tin Plating (tin plating): cans - packaging cans made of iron in lined with tin. Coating is done by electrolysis, called electroplating. Tin is a rust-resistant metal. Tin-coated iron is not corrosive because there is no contact with oxygen (air) and water. However, the tin layer only protects the iron as long as it is intact (without defects). If a layer of tin coating is damaged, such as scratches, the tin actually encourages or accelerates iron corrosion. It happens because iron reduction potential is more negative than lead. Therefore, iron coated with tin will form an electrochemical cell with iron as anode. Thus, lead promotes iron corrosion. But that is what is expected so that the old tin cans are quickly destroyed.
5. Galvanization (zinc plating): Iron pipe, telephone pole, body obil, and various other items lined with zinc. Unlike tin, zinc can protect iron from corrosion even if the lining is not intact. It happens because of a mechanism called cathode protection. Because the iron reduction potential is more positive than zinc, the iron in contact with zinc will form an electrochemical cell with iron as a cathode. Thus, the iron is protected from and oxidized zinc.
6. Cromium plating: iron or steel can also be coated with chromium to provide a shiny protective coating, for example for car bumpers. Cromium plating is also done by electrolysis. Same as zink. Chromium can provide protection even if there is a defective or damaged chromium layer.
7. Sacrifical Protection: magnesium is a much more active metal (meaning more rusty) than iron, then the magnesium will rust but no iron. This method is used to protect steel pipes grown in soil or ships. Periodically, the magnesium bar must be replaced.