CHEM 6.10 Corrosion

Question 1

What is corrosion ?

Answer 1

Corrosion is the breakdown of a metal as a result of chemical reactions with its environment.

Question 2

How does silver corrode ?

Answer 2

Silver, for example, tarnishes when
it comes in contact with sulfur compounds in air.

Question 3

What is beneficial corrosion ? List an example.

Answer 3

Beneficial corrosion is corrosion that benefits us; for art, stop further corrosion, etc.

-When aluminum is exposed to air, it quickly corrodes to form aluminum oxide - tightly coats the underlying aluminum metal, preventing any further corrosion from occurring.

-Copper develops
an attractive greenish patina after being exposed to the atmosphere -so corrosion resistant that a copper roof remains weatherproof
for up to 75 years

Question 4

Following beneficial corrosion, how can we prevent corrosion ?

Answer 4

PROTECTIVE COATING
Cover the metal with a rust-inhibiting paint, chrome, or plastic coating.

CORROSION-RESISTANT MATERIALS
Use materials that do not rust: plastic. Incorporating corrosive-resistant materials to increase resistance: chromium.

GALVANIZING
Steel coated with a thin layer of zinc. As zinc corrodes, it forms a protective oxide layer that sticks to both the zinc layer and any steel that may be exposed. Preventing the steel from corroding.

Question 5

What is Rust ?

Answer 5

A reddish-brown flaky material that forms when metals containing iron corrode. It does stick well to underlying metal and therefore flakes away, exposing materials to further corrosion.

Question 6

What causes Rust ?

Answer 6

The corrosion of iron is impacted by many things: the presence of air, water, and electrolytes, acidity, and mechanical stress.