Rapid Oxidation Of Steel Wool Lab Report

Rapid Oxidation of Steel Wool

Arby D. Dickert

Western Governors University

Rapid Oxidation of Steel Wool

Abstract

The rapid oxidation of steel wool involves an exothermic reaction of iron with oxygen. Due to the decrease in volume of the combustion products compared to the original sample, many students would expect the products would weigh less than the original sample. This investigation determines that the product weighs more than the sample and why this occurs. In addition, properties such as color and magnetism provide additional identification. Keywords: combustion, steel wool, iron, magnetite, ferric oxide When a candle burns, the wax disappears. When wood burns, the wood is reduced to ash to about ten percent of its

In addition, we can predict the percentage increase and use this information to help define the combustion product. Furthermore, we can use the color as well as magnetic properties of the combustion product as additional evidence. In the Astro-Venture course, NASA developed an excellent presentation and experiments for oxidation and combustion. In the course, NASA (2014 p. 119) explains what happens when iron rusts in the presence of water: 4Fe + 3O2 form 2Fe2O3. Four atoms of iron combine with 3 atoms of oxygen to yield two atoms of ferric (iron) oxide. Ferric oxide is formed when iron is oxidized at low temperatures. The ferric oxide is distinguished by its red color. Combined with other substances it is used as a color in paint. Note that the oxygen has now combined with the iron. This implies that the combustion product contains more elements and should have more mass than the original. Ferric oxide is not attracted to a magnet and is not attracted to

The aluminum foil and the steel wool were taken outside onto a concrete driveway and ignited using a match. As the steel burned, I blew on the steel wool to make sure all the steel wool was consumed. I made sure that I did not blow too hard and scatter the combustion products. After making sure that the fire was out and all the fuel was consumed, I brought the aluminum pan now containing the combustion product inside and allowed it to cool to room temperature. Once the aluminum pan and combustion material reached room temperature, I weighed the pan. The results are show in Table 2. We can predict the results we should see using the following equation for the oxidation of iron into magnetite: 3Fe (s) + 2O2 (g) → Fe3O4 (s) Three units of iron with a mass of 56 plus four units of O with a mass of 16. This yields a magnetite combustion product of (3 x 56) + (4 x 16). In other words, 168 units of iron combine with 64 units of oxygen yielding 232 units of magnetite. The oxygen added accounts for a 38% increase in the mass. Instead of the mass of the being reduced, the chemical formula predicts an increase. Similar calculation performed for ferric oxide show a 43% increase in mass. See Table 1 for the predicted percent increase. Thus the percent change in mass may be an indicator of the combustion