CHEMISTRY OFHAZARDOUS MATERIALS

A contractor was hired to do some maintenance work inside a grain silo. Assuming the facility is at sea level, what is the minimum level of oxygen necessary for the contractor to carry out his or her task without using a supplied air respirator?

		16.0%
		19.5%
		20.9%
		23.5%

A soil vapor extraction system equipped with carbon canisters is used to remediate gasoline contamination at a gas station. Which of the following statement is TRUE?

		Activated carbon in the canisters filters the gasoline vapors by the process of absorption.
		Activated carbon is charcoal heated in the absence of air at low temperatures.
		Activated carbon is an effective filter medium for gasoline vapors because of its small surface area.
		Activated carbon in the canisters filters gasoline vapors by the process of adsorption.

During the chlorination of drinking water and wastewater, what is it that makes chlorine an effective microbiocide?

		The formation of hypochlorous acid
		The formation of trihalomethanes
		The formation of hydrogen chloride
		The formation of metallic chloride

Diamond and graphite are the two primary allotropes of carbon. Neither is generally considered hazardous, but they have their own specific uses. Choose which of the following statements is TRUE regarding these allotropes.

		Diamond and graphite undergo phase changes from solid to liquid at moderately high temperature.
		Diamond and graphite do not burn.
		Diamond and graphite have different chemical structures.
		Diamond and graphite are poor conductors of heat.

An employee at a municipal water treatment plant was experiencing chest pain, nausea, and burning of the eyes and throat. The industrial hygienist has determined that it may be due to chlorine exposure at which levels?

		1-hr exposure at 0.5 - 2 ppm
		1-hr exposure at 2 - 20 ppm
		1-hr exposure at > 20 ppm
		8-hr exposure at 1 ppm

Although coal is no longer the favored energy source, U.S. coal mines still produced close to a billion short tons of coal. Match the description of the following chemical products obtained from or related to coal.

	Coke
	Carbon black
	Coal gas
	Coal tar pitch
	Coal tar
	Creosote oil
	Coal tar distillate
	Anthracite
	Lignite
	Charcoal

A.	Any fraction obtained by distilling coal tar
B.	Product obtained from the distillation of coal tar
C.	Residue left after coal is heated to 350 deg C in the absence of air
D.	A finely divided form of carbon that is produced when coal tar burns in a furnace with limited air
E.	Mixture consisting of ammonia, carbon monoxide, hydrogen cyanide, methane, and hydrogen sulfide produced when coal is heated in the absence of air
F.	Coal that has a specific gravity of 1.29
G.	Solid residue that is left when coal and coal tar pitch are heated in the absence of air
H.	Liquid produced from the heating of coal that can be used for waterproofing when sealing roofs
I.	Residue remaining after wood, nut shells or peach pits are heated in the absence of air
J.	Coal that has 0.4 to 1.9% sulfur content

DISCUSSION QUESTIONS

Coal gasification electric power plants are now operating commercially in the United States and in other nations. This technology produces clean-burning hydrogen that can be transferred to customer facilities by pipeline. Hydrogen can also be transported in bulk by highway or rail.

1. If there is a spill of liquid hydrogen, why will it likely burst into flame spontaneously?
2. Why do experts recommend the use of a thermal-imaging camera for detecting a hydrogen leak from a pipe fitting connected to a steel cylinder of hydrogen?

Your total response must be at least 200 words in length.

Liquid oxygen (LOX) is used in the aerospace industry, steel industry, electric power plants, and hospitals.
1. A hospital is installing their own bulk oxygen system due to their large volume of consumption. OSHA regulation 29 CFR 1910.104(b)(2)(iii) requires owners of bulk oxygen systems to provide noncombustible surfacing in areas where liquid oxygen might leak during operation of the system or during the filling of a storage container. If the hospital provides an asphalt surface in areas where oxygen could potentially leak, will they be in compliance? Explain your answer.
2. In a another scenario, what actions should an emergency-response crew take to protect lives, property, and the environment at a collision scene involving separate spills of liquid oxygen and automobile fuel?

Your total response must be at least 200 words in length.