Keep Iron from Rusting
What You Need to Know
A chemical reaction is the change in the arrangement of particles in one or more substances called reactants, resulting in the formation of one or more new substances called products. Corrosion is the slow eating away of a metal due to a chemical reaction. Rusting is a common name for the corrosion of iron in the presence of water and oxygen. Rust is the reddish iron oxide formed by the rusting process.
How Does a Chemical Reaction Work?
In a chemical reaction, the particles making up the reactants break apart and rearrange themselves in a different way. Take a look at the gumdrop-shaped models of chemicals shown in the diagram below. Notice that the same number of each kind of gumdrop in the reactants make up the products. They've just become linked together in a different way.
What Does This Have to Do with Rusting Iron?
Rusting is a chemical reaction. The reactants are iron and oxygen and the product is iron oxide (rust). For rusting to occur, the iron atoms must lose some of their electrons (negative particles that travel around the nucleus of an atom), and the oxygen must gain them. Water is needed for rusting to occur because the electrons that the iron loses travel through the water. The chemical reaction expressed in words for the rusting of iron is:
iron + oxygen yields iron oxide
Real-Life Science Challenge
Steel is a mixture of iron and carbon. One way that scientists have discovered to keep iron in steel from rusting is to galvanize it, which means to coat it with zinc. Zinc is rust-resistant.
Now, start experimenting with iron. How can you prevent it from rusting?
- Use small iron pieces of equal size, such as ungalvanized steel nails.
- Experiment with different ways of coating the iron pieces, such as with oil, paint, or nail polish.
The Titanic is sitting on the ocean bottom at a depth where there is little to no oxygen. Yet iron in the ship is corroding. One evidence of this corrosion are structures, called rusticles, that are huge, rust-colored, iciclelike masses of rust. Instead of oxygen in the water causing this rust, it is created by iron-eating bacteria that have been feasting on the Titanic's iron. The chemical reactions during the bacteria's digestive processes produce the waste that forms the rusticles. Despite their size, the rusticle structures are very fragile and burst into clouds of red dust if they are even lightly touched. Little by little the Titanic is being eaten away. Eventually, it will be a pile of red rust. Some say this may happen in less than 100 years. In the meantime, scientists are working to determine how the bacteria are making this chemical change.
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