Gunpowder combustion products

However, in practice, the energy of the hot combustion products of the gunpowder is never fully utilised in providing forward motion to the shell. Losses occur unavoidably in several ways - as radiation as residual energy of motion of the partially expanded gases as leakage of gas around the shell and as wave motion (noise) in the surrounding atmosphere. 

In present times, the most important use of sulfur is in making sulfuric acid, and although H2S04 is now the most important chemical containing sulfur, this has not always been so. In fact, it is believed that H2S04 was discovered only in about the tenth century. To the ancients, sulfur and its combustion product, S02, were more important Elemental sulfur is one of the components of black gunpowder, so its importance in this area was enormous until the late 1800s when smokeless powder (nitrocellulose) was developed. 

Bursts or puffs of smoke are produced by explosively-dispersing very fine particles (aerosols), either in the form of combustion products or as inert, solid ingredients. These effects are seen in daylight pyrotechnics displays or when firing blanks from artillery pieces. In the latter instance, a brass case loaded with grain gunpowder is fired from the breech to give white smoke, which is in fact an aerosol of mainly potassium carbonate particles. Alternatively, if a bag of fine powder such as charcoal dust is... 

At room temperature, entropy effects are so small that they have little effect on the direction of a chemical reaction unless the difference in AG or 2s.H between reactants and products is correspondingly small. But at the high temperature encountered in pyrotechnic reactions such as the combustion of gunpowder, the relative importance of the change in entropy increases until it becomes a dominant factor. Hence, the importance of the temperature term in the free energy equation. 

The exothermic reaction of discharged oxygen with combustible substances has been utilized for pyrotechnic products, including gunpowders, explosives and fireworks. 

---