Definitions Flashcards
Air reactivity (pyrophoricity)
A substance that ignite spontaneously in air at or below 54.5°C (130.19°F ) most pyrophoric should be extinguished with a class D extinguisher for burning metals
Aromatic hydrocarbon
A hydrocarbon containing the benzene “ring”, which is formed by six carbon atoms and contains resonant bonds. Examples include benzene (C6H6) and toluene( C7H8)
Biological agents and toxins
Biological threat agents consist of pathogens and toxins. Pathogens are disease producing organisms and include bacteria
(e.g. Anthrax, cholera, plague, e coli) and virus (e.g. small pox, viral hemorrhagic fever). Toxins are produced by a
biological source and include ricin, botulinum and mycotoxins.
Blood agents
Chemical agents consist of a cyanide compound, such as hydrogen cyanide (hydrocyanic acid) and cyanogens chloride. These agents are identical to the civilian counterparts used in industry.
Catalyst
Used to control the rate of chemical reaction by either speeding up or slowing it down. If used improperly catalyst, can speed up a reaction and cause container failure due to pressure or heat build up.
Caustic (Base, Alkaline)
Compound that forms hydroxides ion in water. These compounds have a pH of > 7, and caustic solutions will turn litmus
paper blue. Materials with a pH > 12 are considered a strong base. Also known as alkali, alkaline or base.
Chemical change
Chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. These processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. Some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions.
Chemical interaction
Reaction caused by mixing up two or more chemicals together. Chemical interaction of materials within a container may result in a buildup of heat and pressure, leading to a container failure. And other situation, the combine materials may be more corrosive than the container was originally designed to withstand and cause container to breach.
Compound, mixture
Chemical combination of two or more elements in the same element or different ones, that is electrically neutral. Compounds have a tendency to break down their component parts, sometimes explosively
Concentration
The percentage of an acid or base dissolved in water concentration is not the same as strength
Corrosive, corrosivity
The material that causes visible destruction or irreversible alteration to living tissues by chemical action at the point of contact
Cryogenic or liquid heat transfer process
There are three different ways that heat can transfer: conduction (through direct contact)
, convection (through fluid movement) or radiation (through electromagnetic waves). Heat transfer occurs when temperature of objects are not equal to each other and refers to how these differences change to an equilibrium state .
Dose
(1) concentration or amount of material to watch the body is exposed over a specific specific time. The amount of substance ingested, absorbed, and or inhale during exposure. (2) a quantity of radiation or energy, absorbed by the body, usually measured in millirems (mrem)
Dose response (relationship )
Basic principle of toxicology. The intensity of a response elicited by chemical within biologic mechanism is a function of the administered dose.
Endothermic
Characterized by or formed with absorption of heat
Evaporation rate
The speed at which a material changes from a liquid to vapor. As more heat is applied to liquid the evaporation rate increases.
Exothermic
Characterized by or formed with the evolution of heat
Expansion ratio
The amount of gas produced by the evaporation of one volume of liquid at a given temperature. Significant property when evaluating liquid and vapor release of liquefied gas is in cryogenic materials. The greater the expansion ratio, the more gas is produced and the larger the hazard area.
Firepoint
The minimum temperature at which a liquid goes off sufficient vapors that would ignite and sustain combustion. It is typically several degrees higher than the flashpoint. And assessing the risk close by flammable liquid release, greater emphasis placed on the flashpoint, since it is a lower temperature and to stay in combustion is not necessary for significant injuries or damage to occur
Flammable (explosive ) range (LEL & UEL)
The range of gas or vapor(percentage by volume) that will burn or explode if ignition source is present. Lemon in concentrations are commonly called the” lower flammable(explosive) limit” and the” upper flammable(explosive) limit. Below the lower flammable limit, the mixture is Tulane to burn above the upper flammable limit the mixtures too rich to burn. If the gas or vapor is released into oxygen, enriched atmosphere, the final range will expand. Likewise, if the vapors release into an oxygen deficient atmosphere, the flammable range will contract
Flashpoint
Minimum temperature at which a liquid gives off enough vapors that will ignite and flash over but will not burn without the addition of more heat. Significant in determining the temperature at which vapors from flammable liquid are readily available and may ignite.
Half Life
The time it takes for the activity of a radioactive material to decrease to 1/2 of its initial value through radioactive decay. The half life of knownmaterials can range from a fraction of a second to millions of years
Halogenated hydrocarbon
A hydrocarbon with halogen atom for example (chlorine fluorine bromine etc., ) substituted for a hydrogen atom. They are often more toxic than naturally occurring organic chemicals, and they decompose into a smaller, more harmful elements when exposed to high temperatures for a sustained period of time
Ignition (autoignition) temperature
Minimum temperature required to night gas or vapor without a spark or flame being present period significant in evaluating the ease at which a flammable material may ignite