CES Explosive Materials & Chemical Composition 2 — Questions and Answers
Question 1: Which chemical compound is the primary active ingredient in ANFO blasting agents?
- Ammonium nitrate (Correct answer)
- TNT
- PETN
- RDX
Correct answer: Ammonium nitrate
ANFO (Ammonium Nitrate/Fuel Oil) derives its explosive energy primarily from ammonium nitrate (94%) mixed with fuel oil (6%).
Question 2: What is the oxygen balance of a high explosive, and why is it important?
- A measure of excess or deficiency of oxygen relative to complete oxidation of carbon and hydrogen (Correct answer)
- The ratio of detonation pressure to atmospheric pressure
- The percentage of oxygen by weight in the explosive formula
- The amount of oxygen consumed per gram during detonation
Correct answer: A measure of excess or deficiency of oxygen relative to complete oxidation of carbon and hydrogen
Oxygen balance expresses the degree to which an explosive can oxidize its own carbon and hydrogen, affecting the toxicity of fumes and explosive efficiency.
Question 3: TNT (trinitrotoluene) has a negative oxygen balance of approximately -74%. What does this indicate?
- TNT produces significant carbon monoxide and soot because it lacks sufficient oxygen (Correct answer)
- TNT releases excess oxygen that can ignite surrounding materials
- TNT is too stable to detonate without a booster
- TNT has a higher brisance than PETN
Correct answer: TNT produces significant carbon monoxide and soot because it lacks sufficient oxygen
A negative oxygen balance means TNT has insufficient oxygen to fully oxidize its carbon to CO₂, resulting in black smoke and CO in post-blast gases.
Question 4: Which of the following is classified as a primary explosive due to its extreme sensitivity to initiation stimuli?
- Lead azide (Correct answer)
- ANFO
- Emulsion explosive
- PETN
Correct answer: Lead azide
Lead azide is a primary explosive that is highly sensitive to heat, friction, and impact, making it suitable for use in detonators.
Question 5: What distinguishes a 'deflagration' from a 'detonation' at the chemical level?
- Deflagration is subsonic combustion; detonation involves a supersonic shock wave driving the chemical reaction (Correct answer)
- Deflagration produces more energy per gram than detonation
- Detonation requires more confinement than deflagration
- Deflagration only occurs in primary explosives
Correct answer: Deflagration is subsonic combustion; detonation involves a supersonic shock wave driving the chemical reaction
In detonation, a supersonic shock wave propagates through the explosive and initiates the chemical reaction, while deflagration propagates by heat transfer at subsonic speeds.
Question 6: RDX (cyclonite) is widely used in military explosives and detonating cord. What is its chemical name?
- Research Department Explosive / cyclotrimethylenetrinitramine (Correct answer)
- Reactive Decomposition Explosive / dinitrotoluene
- Rapid Detonating eXplosive / nitroglycerin
- Regulated Demolition eXplosive / ammonium perchlorate
Correct answer: Research Department Explosive / cyclotrimethylenetrinitramine
RDX stands for Research Department Explosive and is chemically known as cyclotrimethylenetrinitramine (C₃H₆N₆O₆), a nitroamine high explosive.
Question 7: What role does the sensitizer play in an emulsion explosive formulation?
- It lowers the activation energy required for detonation, increasing sensitivity to a booster (Correct answer)
- It acts as the oxidizer that reacts with the fuel droplets
- It prevents crystallization of ammonium nitrate at low temperatures
- It increases the water resistance of the emulsion
Correct answer: It lowers the activation energy required for detonation, increasing sensitivity to a booster
Sensitizers such as glass microballoons or hollow microspheres create hot spots that lower the energy threshold required to initiate detonation in emulsion explosives.
CES Explosive Materials & Chemical Composition 2
Which chemical compound is the primary active ingredient in ANFO blasting agents?