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Emergency responders spend considerable amounts of time preparing for fires, medical incidents, police calls and industrial accidents. They take courses in rescue, firefighting, medical treatment and law enforcement. A large number of emergency responses involve hazardous materials but many responders shy away from "hazmat," and "freak out" at any mention of the word chemistry! The reality, though, is this — you need a basic understanding of the physical and chemical characteristics of hazardous materials to deal with them effectively.
This is the first of a series of columns that will provide emergency response personnel with a view of chemistry as it applies to the hazardous materials encountered in daily responses. Some of the concepts presented here may bend the rules of chemistry a bit. However, the purpose of this approach is not to educate chemists but to teach response personnel about basic chemistry.
This study of chemistry for the purpose of hazmat response may be considered "street chemistry." The concepts presented work in the street application of chemistry when dealing with hazardous materials. This series gives fire, police, EMS and other emergency personnel some basic tools to better understand hazardous chemicals. The information may help keep you from being injured or killed at the scene of a hazmat incident.
Inorganic Vs. Organic
Chemistry is the study of matter. Most chemicals can be divided into two families: inorganic and organic. Acids, bases, salts and certain elements are some materials studied with inorganic chemistry. Organic chemistry is the study of compounds that all contain carbon and a few other elements such as oxygen, nitrogen, fluorine, chlorine and bromine.
Matter is defined as "anything that occupies space and has mass." Matter exists in three basic forms: solids, liquids and gases. Examples of hazardous materials in liquid form would be gasoline, alcohol and benzene. Among the gases are ammonia, propane and chlorine. Solids include phosphorus, ammonium nitrate and sodium peroxide.
Temperature and pressure have a bearing on the physical state of a chemical but do not change the chemical properties. Oxygen is a gas under normal temperatures and pressures. When oxygen is pressurized to a certain point and cooled by the ultimate release of pressure, it becomes a cryogenic liquid but maintains all of its chemical properties. Water is a liquid at normal temperatures and pressures but if exposed to temperatures below 32 degrees Fahrenheit it becomes a solid. The solid form of water maintains all of the chemical properties of liquid water. If water is heated above 212 degrees F, it becomes a gas but maintains all of the chemical properties of liquid water.
The hazard presented by a chemical may be affected by the physical state of the material when it is encountered. For example, only gases burn. Solids and liquids do not burn, even though they may be listed as flammable. A solid or liquid must be heated until it produces enough vapor to burn. Water has a cooling effect on the skin as a liquid but when it is turned into a gas, water causes burns to the skin.
There are some intermediate steps in the process of classifying solids, liquids and gases. Some solids may have varying particle sizes from large blocks to filings, chips and dusts. Particle sizes of vapors may vary from invisible vapors that are very small to mists and droplets that are readily visible.
The smallest part that an element can be divided into, by normal means, is an atom. Atoms of elements are chemically combined with atoms of other elements to form compounds. Dividing a compound into its smallest part would create a molecule. Molecules of compounds contain different types of atoms bonded together in fixed proportions.