Metals Brass Lead Iron Aluminum One Metal example essay topic

Corrosion and rubbing alcohol vs. corrosion and hydrogen peroxide " Are brass, lead, iron, and aluminum more likely to corrode in solutions of rubbing alcohol or hydrogen peroxide?" a. Definition-corrosion, rust, oxidation Corrosion is the atmospheric oxidation of metals. Rusting is essentially a process of oxidation in which iron combines with water and oxygen to form rust. Rust is the reddish-brown crust that forms on the surface of iron.

Rust, a chemical compound, is a hydrated ferric oxide Fe 2 O 3. nH 2 O, where n is usually 11/2. The chemical mechanism of rusting is not fully known, but is thought to involve oxidation of metallic iron to ferrous ion, (Fe++) and reaction of the ferrous ion with oxygen and water to form rust. This reaction is catalyzed by water, acids, and metals (e. g., copper and tin) below iron in the electromotive series. Because iron is so widely used, e. g., in building construction and in tools, its protection against rusting is important. Although metals (e. g., aluminum, chromium, and zinc) above iron in the electromotive series corrode more readily than iron, their oxides form a tenuous coating that protects the metal from further attack. Rust is brittle and flakes off the surface of the iron, continually exposing a fresh surface.

Rusting can be prevented by excluding air and water from the iron surface, e. g., by painting, oiling, or greasing, or by plating the iron with a protective coating of another metal. Metals used for plating include chromium, nickel, tin, and zinc. Zinc plating is called galvanizing. (web). Many alloys of iron are resistant to corrosion.

Stainless steels are alloys of iron with such metals as chromium and nickel; they do not corrode because the added metals help form a hard, adherent oxide coating that resists further attack. The iron hulls of ships can be protected against rusting by attaching magnesium strips to the underside of the vessel. An electric current is generated, with the magnesium and iron acting as electrodes and seawater acting as the electrolyte. Because magnesium is above iron in the electromotive series, it serves as a 'sacrificial anode and is oxidized in preference to the iron. This is called cathodic protection, since the iron serves as the cathode and thus escapes oxidation.

This method is also used to protect the pipes of electric generating plants where saltwater is used as a coolant.) (web). The involvement of water accounts for the fact that rusting occurs much more rapidly in moist conditions as compared to a dry environment such as a desert. Many other factors affect the rate of corrosion. For example the presence of salt greatly enhances the rusting of metals. This is due to the fact that the dissolved salt increases the conductivity of the aqueous solution formed at the surface of the metal and enhances the rate of electrochemical corrosion.

This is one reason why iron or steel tend to corrode much more quickly when exposed to salt (such as that used to melt snow or ice on roads) or moist salty air near the ocean.) (web). b. The Metals Brass Lead Iron Aluminum One metal that will be used over the course of the experiment is iron. The combination of oxygen and water causes the product of iron's corrosion to be a differing type of the metal, which is hydrated iron oxide. This new form of the iron appears to be heavier and bulkier, but small porous holes have actually formed, causing the new solution to be very brittle and thin. The equation that applies to the corrosion of iron is: The formation of rust can occur at some distance away from the actual pores in the piece of iron as you can see in the diagram of the process that is shown above. (This corrosion / rusting of iron that is shown above along with the included equations was taken from web) Another metal that will be used is aluminum.

Aluminum does not corrode under normal atmospheric conditions. During the first stage of oxidation, the aluminum metal rapidly begins to corrode. As it does so, a thin layer of oxide that has been produced because of the process lays over the metals's surface. This acts as a protective "skin" to the piece of metal so that it may no longer be corroded at such a rapid pace. Lead is a heavy metal and is a basic chemical element.

Lead can be combined with many other substances to form numerous compounds. It is similar to aluminum during the process of oxidation. Although less active than aluminum, they are both protected by similar oxide films. Pieces of Lead frequently corrode. Corrosion may be so severe as to completely consume the piece, leaving behind a white or gray residue, which is aptly referred to as 'lead disease,' 'lead rot,' 'lead cancer,' or 'lead bloom. ' c. Chemical Properties Chemically, the metals differ from the nonmetals in that they form positive ions and basic oxides and hydroxides.

Upon exposure to moist air, a great many undergo corrosion, i. e., enter into a chemical reaction; e. g., iron rusts when exposed to moist air, the oxygen of the atmosphere uniting with the metal to form the oxide of the metal. Aluminum and zinc do not appear to be affected, but in fact a thin coating of the oxide is formed almost at once, stopping further action and appearing unnoticeable because of its close resemblance to the metal. Tin, lead, and copper react slowly under ordinary conditions. Silver is affected by compounds such as sulfur dioxide and becomes tarnished when exposed to air containing them.

The metals are combined with nonmetals in their salts, as in carbides, carbonates, chlorides, nitrates, phosphates, silicates, sulfides, and sulfates. (encyclopedia. com / articles : 2000) d. The Electromotive Series On the basis of their ability to be oxidized, i. e., lose electrons, metals can be arranged in a list called the electromotive series, or replacement series. Metals toward the beginning of the series, like cesium and lithium, are more readily oxidized than those toward the end, like silver and gold. In general, a metal will replace any other metal, or hydrogen, in a compound that it precedes in the series, and under ordinary circumstances it will be replaced by any metal, or hydrogen, that it follows. (ask. com / corrosion ) e. Rubbing Alcohol Components Isopropyl alcohol is a clear, colorless liquid with a somewhat bitter taste and a smell of acetone. Rubbing alcohol contains: vs. 70% Isopropyl Alcohol Small increments of water Methanol, vs. Ethanol, vs. And / or ethylene glycol. f.

Corrosion and Rubbing Alcohol Because the rubbing alcohol has some amounts of water in it, as well as a "stripping" component, (used for eliminating germs), I believe that testing the different metals in solutions of alcohol instead of just plain water could actually increase corrosion. There are also hydrocarbons in the mixture of rubbing alcohol. Hydrocarbons are basically bonds of hydrogen and carbon. Hydrocarbons can also assist in the progression as well. Just as salt water helps speed the process, a product that has added strength such as the Isopropyl alcohol should aid with the corrosion's speed in the different types of metals. 2 H 2 O 2 2 H 2 O + O 2 (hydrogen peroxide water + oxygen) g.

Components of Hydrogen Peroxide.