Question #15286

Feb 15, 2016

Explanation:

Fireworks produce three kinds energy.
1. Produce loud bang or noise.
2. Produce lot of heat.
3. Produce bright light of various colors.

Gunpowder is main ingredient of all kinds of fire works. This is black mixture of three compounds. It consists of Potassium Nitrate ${\text{KNO}}_{3} ,$ 75%, Charcoal $\text{C}$, 15%, and Sulfur $\text{S}$, 10%; all three mixed by weight.

The sulfur and charcoal burn as fuels, and the Potassium Nitrate (saltpeter) is an oxidizer.

Resulting reaction produces energy in the form of heat, light and sound. Burning of charcoal, is simply slow combustion of carbon in air (ambient oxygen being the “oxidizer”) making ${\text{CO}}_{2}$, and giving off heat and light.

${\text{4KNO"_3->2"K"_2"O"+2"N"_2+5"O}}_{2}$

${\text{O"_2(g)+"S"(s)->"SO}}_{2} \left(g\right)$

${\text{O"_2(g)+"C"(s)->"CO}}_{2} \left(g\right)$

In newer fireworks chemical oxidizer, such as Potassium Perchlorate ${\text{KClO}}_{4}$, is used which gives off its oxygen much more rapidly.

${\text{KClO"_4->"KCl"+2"O}}_{2}$

The color of the fireworks is due to light emitted by certain salts. The atoms of element contained in the salt are excited to higher energy levels due to immense heat produced in the firework. Thereafter, the excited atoms return to the ground state emitting electromagnetic radiation of characteristic frequency. This radiation is seen by the viewer as emitted color.

Sodium $\text{Na}$ produces yellow color, Barium $\text{Ba}$ emits green and Copper $\text{Cu}$ gives blue.

To produce red color fireworks strontium salts, and lithium salts are used.
Lithium carbonate, ${\text{Li"_2"CO}}_{3}$ emits red
Strontium carbonate, ${\text{SrCO}}_{3}$ emits bright red