Oxidation of Iron An example of a Combination

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

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

Part 1: Rusting of Iron Filings 1. 2. 3. 4. Put cotton ball into a 1 oz 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

Part 2: Steel Wool 1. 2. 3. 4. 5. 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

Looking back at Part 1 • Look back at the iron filings. • Equation: 4 Fe + 3 O 2 2 Fe 2 O 3 Before: no rust After: orange color

Return to Part 2. 1. Measure the temperature of the steel wool in the plastic bag now. NOTE: Now at 90 degrees.

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.

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.