Smoke
Background
Smoke is caused by any particularised solid suspended in
the atmosphere. This is caused by incomplete combustion
of a substance and or reaction products which are solid,
hence, a smokeless campfire is very hot and is comprised
largely of medium sized pieces of wood which do not burn
too quickly or not smoulder becasue they are too big.
There are many ways of producing smoke, many of which use
an organic fuel. The one described here uses an organic
fuel and is fairly non-toxic. Other smoke producing compositions
use such things as rubber, plastics, phosphorous, etc.
Composition
| Ingredient
|
Formula
|
Quantity
|
| sucrose/sugar |
C12H22O11
|
1-3 parts |
| potassium nitrate |
KNO3 |
1-4 parts |
|
Different proportions give different effects, for instance,
less potassium nitrate causes there to be a lot of carbon
left over which has not been burned. It is also possible
to add sulfur, which will cause there to be a larger, hotter
flame.
Some icing sugars (known as icing mixture) contain starch,
which will still work but will probably cause the mixture
to burn more slowly. It may be a good idea to buy sucrose
from a chemical supplier.
Equations
This is what would happen in an ideal world:
5C12H22O11(s) + 48KNO3(s) => 24K2CO3(s) + 36CO2(g) +
55H2O(g) + 24N2(g)
Unfortunately we don't live in an ideal world and so you
could very easily get any of the following as a result of
incomplete combustion, thermal decomposition, etc:
KNO2 (KNO3 that hasn't been fully reduced and is left as
the nitrite)
NO2 (from thermal decomposition of the KNO3)
C + H2O (from thermal decomposition of the sugar)
CO (from incomplete combustion of the sugar)
