Chemistry- Explosives (Extra) Flashcards
(15 cards)
1
Q
explosives should have
A
- negative H: exothermic, release heat and energy
- positive S: increase entropy, create lots of gases
- negative G: spontaneous
2
Q
main characteristics of an explosive
A
- extremely fast reaction
- release lots of heat and gases
3
Q
low explosives
A
- release large quantities of energy slowly
- useful as a propellant
- undergoes deflagration (subsonic combustion, slower than the speed of sound)
4
Q
gun powder
A
- ex. of low explosive
- components:
- flammable component (C)
- oxidizing substance (KNO3)
- catalyst (S)
5
Q
nitrocellulose/ gun cotton
A
- ex. of low explosive
- components:
- flammable component (C)
- oxygen source directly incorporated to the structure (NO2 nitro group)
6
Q
high explosives
A
- release large quantities of energy rapidly
- detonates: produces a shock wave that travels through the material (faster than the speed of sound)
- doesn’t need oxygen
7
Q
nitroglycerin
A
- ex. of high explosive
- discovered in the 1840s
- heavy, yellow oil
- highly sensitive to impact
8
Q
trinitrotoluene/ TNT
A
- ex. of high explosive
- discovered in the 1860s
- yellow solid
- insensitive to friction and impact
9
Q
RDX
A
- ex. of high explosive
- discovered in thr 1920s
- white, crystalline solid
- insensitive to impact and friction
10
Q
Common characteristics of explosives
A
- contain carbon fuel source
- contain NO2 groups, very unstable
- combust rapidly to form gases
11
Q
sensitivity
A
refers to the ease that a material may be ignited or detonated (activation energy)
12
Q
impact
A
how hard can it be hit before exploding?
13
Q
friction
A
can it be scratched without exploding
14
Q
heat
A
what temperature can the material withstand before exploding
15
Q
brisance
A
- shattering potential of the explosion or the speed of the reaction
- affected by the nature of material and degree of confinement
