Chemistry of Fire

The chemical chain reaction which takes place with the evolution of heat and light is simply known as fire. Fire is an exothermic, self-sustaining chemical reaction that involves a solid, liquid, or gas-phase fuel and is typically associated with the oxidation of this fuel by atmospheric oxygen, which results in the emission of energy in the form of heat and light. In other words, a fuel and oxygen undergo a chemical reaction known as combustion that produces carbon dioxide and water. It is an exothermic reaction, which means that it generates heat. This is because the oxygen molecule's chemical connections are relatively weak, and the new bonds created are more stable, leading to a net production of energy.

Many of us had the basic combustion equation for fire drilled into us in school: fuel + oxygen = carbon dioxide + water. However, carbon dioxide is not produced in a direct chain during combustion events. As an alternative, numerous intermediary molecules are used throughout the way. These intermediate molecules can occasionally be created in extremely high amounts as a result of incomplete combustion. For instance, a flame that receives insufficient oxygen may create carbon monoxide rather than carbon dioxide.

When two gases react, creating both heat and light, a flame is created. Some flames burn hotter than others because different gases react in different ways and produce different quantities of energy. For example, a domestic candle's flame can burn at temperatures between 800 and 1000 degrees Celsius. By altering the reaction, for as by substituting pure oxygen for air, a flame can be made to burn at a greater temperature. Oxy-acetylene, which is created by burning a mixture of oxygen and acetylene, produces a flame that burns at over 3000°C and can be used to cut, melt, and weld metals.

Each stage of the process and all of the intermediate molecules involved, which naturally vary depending on the fuel, are still not entirely understood. This is one reason why we started studying fire in space; without the interference of gravity, it is simpler to investigate the more intricate aspects of combustion.

Conditions for a fire:

Oxygen in air As stated in the definition of fire, air oxygen is typically the oxidizing agent. The fact that oxygen makes up about 20% of the atmosphere, as will be detailed later, typically makes it simple to understand why it is actually present. The availability of oxygen, however, plays a crucial role in the intensity and spread of a fire.

Other oxidizing agents, such as potassium chlorate (KClO3) and sodium nitrate (NaNO3), which have oxygen in their chemical makeup, can provide oxygen to a fire under the right circumstances. Additionally, in extremely unusual circumstances, combustion can take place in an environment of carbon dioxide or another gas without oxygen.

Fuel Practically, any substance that exists in a chemical state where it may be oxidized by oxygen in the presence of a suitable ignition source can be regarded as the fuel mentioned in the definition.

In fire investigations, organic substances with considerable concentrations of carbon (often 50% and more) and hydrogen are the most frequent fuels that need to be taken into account. Natural substances like wood, cotton, and so on are among them, as are synthetic substances like plastics, paints, rubbers, and so forth, as well as refined fuels and solvents like gasoline, lighting kerosene, and methylated spirits.

Heat Energy is required to excite both the fuel and oxygen molecules to the active state essential for chemical reaction. The ignition temperature of the fuel is the lowest temperature required to start the "self-sustaining chemical reaction" mentioned in the definition of fire. Fire investigators are primarily interested in the source of ignition because this can be used to determine the cause of the fire.

Chemistry Behind Colors

 When you think about it, color is kind of strange. Think about the different colors that you see around you every day. Each one of them has its own distinct properties, and yet they all seem to share some basic similarities. There are lots of different types of colors, but they are all variations of three primary colors: red, yellow, and blue. Red, yellow, and blue are also known as the primary colors because these three types of light can combine to create any other color on the spectrum.

 The result is a series of blue-green color combinations, the most common being red, yellow and green. All together these are usually referred to as 'red' or 'violet'.

It's not just about making it easier for people who want to buy organic cosmetics but more importantly because they could also benefit from this process – allowing them greater control over when their own skin gets affected by environmental pollution (including pesticides). "Most beauty products carry chemicals which make that happen," explains Professor Simon Morris, director general at British Cosmetics Association. Some have active ingredients such an insect repellent spray; others contain tiny amounts in soaps.

 These three (Red, yellow, and blue) hues are also the simplest to identify in a visual test because almost everyone can identify them as being one of those three hues. So what makes these specific colors so special? Let’s find out!

1. Blue

Blue color comes from the chemical structure of indigo. Indigo is a blue-colored dye extracted from plants of the genus Indigofera. It is produced by the oxidation of indole (a derivative of tryptamine) to indoxyl sulfate.

2. Green

 Green color comes from the chemical structures of chlorophyll and carotene. Chlorophyll is a green pigment present in all plants. Carotene is a yellowish orange pigment found in carrots and some fruits and vegetables.

3. Red

 Red color comes from the chemical compounds of anthocyanin. Anthocyanins are red pigments found in many flowers, berries, and roots.

4. Yellow

 Yellow color comes from the chemical compound of flavonoids. Flavonoids are yellow pigments found in many foods including apples, citrus fruits, onions, and chrysanthemums.

5. Orange

 Orange color comes from the chemical composition of lycopene. Lycopene is a reddish orange pigment found in tomatoes, watermelons, and guavas.

6. Purple

 Purple color comes from the chemical components of betalains. Betalains are purple pigments found in beetroot, amaranth, and pansies.

7. Brown

 Brown color comes from the chemical compositions of tannins. Tannins are brown colored pigments found in tea, wine, and oak trees.