1. Oxidation of Iron - An example of a Combination Reaction
Vanderbilt Student Volunteers for Science
Training Presentation
Spring 2012

2. Introduction
Oxidation: Oxidation usually occurs when an element or compound combines with oxygen.
Apples turn brown after they have been cut and left exposed to the air.
Iron is oxidizing when it rusts and turns a reddish color
This example of rusting is called a combination reaction
Rust = iron oxide

3. Part 1: Rusting of Iron Filings
Put cotton ball into a 1oz cup and sprinkle with iron filings.
Sprinkle a small scoop of salt
Add a squirt of Hydrogen Peroxide
Set aside and observe after starting part 2.
*the obvious orange color forms within 2 minutes

4. Part 2: Steel Wool Put steel wool into plastic bag
Put plastic bag into cup (line it like a garbage can)
Add a spoonful of salt and the rest of the peroxide.
Feel the bag and note the temperature (Should be at room temperature)
Measure the temperature again in 1 minute
Steel wool piece
Line like a garbage can

5. Looking back at Part 1 Look back at the iron filings.
Equation: 4Fe + 3O2  2Fe2O3
Before: no rust
After: orange color

6. Return to Part 2.
Measure the temperature of the steel wool in the plastic bag now.
NOTE: Now at 90 degrees.

7. Conclusion The reaction in this experiment was a COMBINATION REACTION
The temperature of the iron filings plus peroxide plus salt mixture increases, so the reaction is EXOTHERMIC.

8. Clean Up Wipe thermometers and bring them back.
Seal plastic bags and throw away in trash can.
If the school does not want you to put it in their trash, put all the bags in a larger bag and bring back to the VSVS lab.