How the coating of steel wool affects its rusting rate

[jisell9036]

I'm doing a science experiment on how the coating of steel wool affects its rusting rate. I'm doing the background information right now. What I need help with is how to make sense of the chemical reaction of rust. Can someone give me examples of these things so it makes sense??

Corrosion is an electrochemical process that involves an anode, an electrolyte and a cathode. An anode is a piece of metal that readily gives up electrons. An electrolyte is a liquid that helps electrons move, and a cathode is a piece of metal that readily accepts electrons. When a piece of metal corrodes, the electrolyte helps provide oxygen to the anode. As oxygen combines with the metal, electrons are set free. When they flow through the electrolyte to the cathode, the anode metal disappears, being converted into rust.

 

[ek]

I'm a little rusty on my high school chemistry, but I think the zinc(or magnesium?) acts as a sacrificial anode and cathodically protects the iron.

So instead of the oxidation reaction being

Fe -> Fe3+ + 3e-

it is

Zn -> Zn2+ + 2e-

because Zinc is a stronger reducing agent.

I probably have some of that information backwards, but that's the idea at least. What grade science or chem is this project for? Have you taken electrochemistry or any oxidation/reduction before?

 

[Learning Curve]

ek:
are you talking about when you say a stronger reducing agent, that Zinc is higher on the activity list than Fe? So it will take the place of the iron. And could you explain how the electrolytes work in this equation?

 

[ek]

ek:
are you talking about when you say a stronger reducing agent, that Zinc is higher on the activity list than Fe? So it will take the place of the iron. And could you explain how the electrolytes work in this equation?

Zinc is lower on the list of Standard Reduction Potentials of Half-Cells. This means it is a stronger reducing agent, weaker oxidizing agent and will be more readily oxidized than iron, thus making it a sacrificial anode.

If you have Acrobat Reader, you can get the full table on the LAST page of this document:


http://www.bced.gov.bc.ca/exams/pdfs/0406ch_P.pdf

Electrolyte: Conducting liquid in an electrochemical or electrolytic cell.

I don't think electrolytes have any bearing on galvanized steel wool.