Chemisty

Oxidation in metals

Team: Oscar, Antonio, Juan, Ale, Zarek

What is Oxidation?

The oxidation of metals is a chemical reaction that results in a metallic oxide, which is referred to as corrosion, as it causes a change in the chemical composition of the metal.

Corrosion

Corrosion and oxidation are chemical processes that involve the interaction of a material, usually a metal, with its environment, resulting in deterioration or degradation of the material.

Oxidation: It is a chemical reaction in which an atom or molecule loses electrons. In the case of metals, oxidation occurs when the metal reacts with oxygen in the air or water, forming an oxide. A common example is when iron oxidizes upon contact with oxygen and forms iron oxide (Fe₂O₃), commonly known as "rust."

Corrosion: It is a broader process that includes oxidation, but can also involve other mechanisms of material deterioration. Corrosion is the progressive wear of metals due to chemical reactions with their environment. In addition to oxidation, corrosion can include reactions with other elements such as chlorine or sulfur. For example, iron can corrode when in contact with salt water, which accelerates the formation of rust and other corrosive substances.

In short, oxidation is a type of chemical reaction that can cause corrosion, but corrosion includes a variety of processes that can damage a material over time.

What is "rust"

Types of Oxidation Oxidation, a chemical process involving the loss of electrons or an increase in oxidation state, can occur in various ways. Here are some of the common types: 1. Direct Combination with Oxygen Example: Rusting of iron Reaction: 4Fe + 3O₂ → 2Fe₂O₃ 2. Reactions with Oxidizing Agents Example: Reaction of copper (Cu) with nitric acid (HNO₃) to form copper nitrate (Cu(NO₃)₂) and nitrogen dioxide (NO₂). Reaction: Cu + 4HNO₃ → Cu(NO₃)₂ + 2NO₂ + 2H₂O 3. Loss of Hydrogen Example: Dehydrogenation of ethanol (C₂H₅OH) to form ethanal (CH₃CHO). Reaction: C₂H₅OH → CH₃CHO + H₂ 4. Increase in Oxidation State Example: Oxidation of sulfur (S) to sulfur dioxide (SO₂). Reaction: S + O₂ → SO₂ 5. Electrochemical Oxidation Example: Oxidation of zinc (Zn) at the anode of a galvanic cell. Reaction: Zn → Zn²⁺ + 2e⁻ 6. Biological Oxidation Example: Respiration in living organisms, where glucose (C₆H₁₂O₆) is oxidized to carbon dioxide (CO₂) and water (H₂O). Reaction: C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O

What are all metals that oxidize on contact with oxygen?

1. Oxidation of Base Metals: Most metals oxidize when they are in contact with oxygen. This process involves a chemical reaction where the metal loses electrons and oxygen gains them, forming metal oxides. For example: • Iron (Fe): Oxidizes to form iron oxide (Fe₂O₃), commonly known as rust or rust. • Copper (Cu): Oxidizes to form a green patina of copper oxide (Cu₂O).