Chemistry 1010

Explosives

Black Powder

Early explosives were made from mixing pure elements and salts into a combustible powder.

15 % wood charcoal

10 % sulfur75 % salt peter (KNO3 – From Bird Droppings)

Black Powder

Chemical Reaction

10 KNO3 + 11 C + 4 S 5 CO + 5 CO2 + 5 N2 + K2CO3 + 3 K2SO4 + K2S gases

From yahoo images

smoke

Why Do Things Explode

• Demo – Vinegar and Baking Soda

From yahoo images

Firecracker

Why does it make the noise?

From yahoo images

So How Does A Bullet Work?

From yahoo images

High Explosives

• The discovery of Gun Cotton

From yahoo images

High ExplosivesDiscovery of nitroglycerine• 1867 Alfred Nobel patented

nitroglycerine• too unstable for real use in blasting

and warfare• When mixed with charcoal or silicon it

is stable• This is called dynamite• These discoveries brought Nobel a lot

of money• In his will, he left money to start the

Nobel Prize• This is still awarded annually to great

scientists

What Makes an Explosive

• Molecule with highly strained bonds

• A molecule with weakly bonded atoms

• Bonds should give off lots of energy when broken

• A molecule that when reacted produces products with very strong bonds

Energy released is the difference in energy given off when a bond breaks and the energy

absorbed when a bond forms

Weak Bond

High Explosives

• Trinitrophenols – explosive due to the easily broken N-O bond

picric acid

Picric acid was a very unstable explosive which would explode unexpectedly

Trinitrotoluene (TNT)

TNT is more stable and need detonation to explode – better bombs

C4 Explosive

See How stuff works dot com– http://science.howstuffworks.com/c-41.htm

See youtube

http://www.youtube.com/watch?v=sdBQtfRS6mI