History Week Project

 

The Chemistry of Black Powder

 
A representative chemical equation for the combustion of black powder:
10KNO3 (s) + 3S (s) + 8C (s) → 2KCO3 (s) + 3K2SO4 (s) + 6CO2 (g) + 5N2 (g)
Because of the different "recipes" for black powder, its combustion cannot be represented by a single equation.
One experimental study showed the following products (in order of descending quantities):
  • 55.91% solid products:
    • potassium carbonate
    • potassium sulfate
    • potassium sulfide
    • sulfur
    • potassium nitrate
    • potassium thiocyanate
    • carbon
    • ammonium carbonate
     
  • 42.98% gaseous products:
    • carbon dioxide
    • nitrogen
    • carbon monoxide
    • hydrogen sulfide
    • hydrogen
    • methane
     
  • 1.11% water
Black powder is a "low power" explosive, producing much less energy than modern smokeless "gunpowder". Combustion converts less than half the mass of black powder to gas. The rest ends up as a thick layer of soot inside the barrel. In addition to being a nuisance, the residue from burnt black powder is an anhydrous caustic substance. When moisture is absorbed, the potassium oxide turns into potassium hydroxide, which will corrode metal gun barrels. Black powder arms must be well cleaned both inside and out to remove the residue.

 
Day 1 Assignment:

  1. What is the purpose of the KNO3 in the equation at the top of the page?
  2. Write the chemical formula for each of the black powder combustion products listed by the experimental study cited above. Use this Tiger Chemistry page for information about chemical formulas.

Day 2 Assignment: Use this Wikipedia page for today's assignment.
  1. Black powder is composed of three substances. What are these substances, and the percentage of each, in black powder?
  2. Black powder combustion produces a LOT of smoke. Which reaction products are responsible for most of that smoke?
  3. What does the fact that less than 50% of the products from black powder combustion are gaseous tell you about the velocity of projectiles fired by black powder weapons?
  4. What substances, by percentage, are used in today's "smokeless gunpowder"?
  5. Why is the combustion of smokeless powder more efficient than the combustion of black powder?
  6. List at least four advantages that today's "smokeless gunpowders" have over black powder.
  7. If "smokeless gunpowder" at been available at the time, it could not have been used. Why?

Day 3 Assignment:
  1. Read the following materials in the order presented.

Day 4 Assignment: Use what you learned from yesterday's readings to answer the following:
  1. Why was the commercial manufacture of black powder during the time of the mid-1800's so dangerous?
  2. What steps in the manufacturing process made the job less dangerous?
  3. What special equipment was used in the manufacturing process to make the job less dangerous?
  4. What special clothing was worn by those making black powder?
  5. At the "mill-cake" state, black powder is at its greatest strength. What is the purpose of the remaining manufacturing process?
  6. Before "polishing", black powder is a dull grayish-brown color. After polishing, black powder is bluish-black. What does polishing do that changes the color of black powder?

Lab Assignment

 
Extension:

Harry Turtledove is one of my favorite authors. He is widely known for the alternative history, Guns of the South, a story about time travelers delivering 100,000 AK-47 rifles, with an unlimited amount of ammunition, to the Southern army in 1864.

Google Books has an online preview of Guns of the South.

In the story, General Lee's army first used the AK-47s in the Battle of the Wilderness.

Question:

    How would the introduction of automatic weapons using high-velocity smokeless gunpowder have changed this battle?
 

Advanced Research: