Alkanes Combustion

Complete combustion of alkanes occurs when an alkane is heated in the presence of sufficient air or oxygen, resulting in the formation of carbon dioxide and water, as well as the release of vast amounts of heat energy.

Alkanes can also be utilised as a fuel because they generate a significant quantity of heat.

When there is not enough oxygen available for the fuel to react entirely, incomplete combustion of alkanes happens, and it is called incomplete combustion of alkanes. 

Carbon dioxide and carbon monoxide are produced as a result of this process. Carbon monoxide, which is generated as a by-product, is a colourless deadly gas that can be inhaled

The carbon black formed during the incomplete combustion of alkane is utilised in the production of inks and other pigments for printing.

If a hydrocarbon is completely ignited, it will emit a blue flame as a result of the combustion. 

As the molecular mass of the hydrocarbon grows, it begins to burn, producing a yellow-colored flame that indicates incomplete combustion. 

The combustion of hydrocarbons becomes more difficult as the molecular weight of the molecule increases.

Nature of Alkanes 

In organic chemistry, an alkane, commonly known as paraffin (a historical euphemism that has several meanings), is an acyclic saturated hydrocarbon with a ring structure.

A simple definition is that an alkane is made up of hydrogen and carbon atoms that are arranged in a tree structure, with all of the carbon–carbon bonds being single.

Alkanes contain the typical chemical formula CnH2n+2, which stands for carbon, hydrogen, and oxygen. 

They range in complexity from the simplest case of methane (CH4), where n = 1 (which is sometimes referred to as the parent molecule), to arbitrarily large and complex molecules, such as pentacontane (C50H102) or 6-ethyl-2-methyl-5-(1-methylethyl)octane, which is an isomer of tetradecan, which is the most complex (C14H30).

Acyclic branched or unbranched hydrocarbons with the general formula CnH2n+2 and comprised solely of hydrogen atoms and saturated carbon atoms, according to the International Union of Pure and Applied Chemistry (IUPAC), are what alkanes are. 

In some sources, the phrase saturated hydrocarbon is used to refer to any saturated hydrocarbon, including those that are either monocyclic (such as the cycloalkanes) or polycyclic, despite the fact that they all have a separate general formula (i.e. cycloalkanes are CnH2n).

Alkanes are composed of one carbon atom that is sp3-hybridized with four sigma bonds (either C–C or C–H), and one hydrogen atom that is connected to one of the carbon atoms (in a C–H bond). 

The carbon skeleton or carbon backbone of a molecule is the longest continuous series of linked carbon atoms found in that molecule. 

According to certain definitions, the number of carbon atoms in an alkane is the size of the alkane.

Effect of Temperature and pressure

Standard temperature and pressure (STP) are standard sets of circumstances for experimental measurements to be produced in order to allow comparisons to be made between different sets of data. 

Standard temperature and pressure (STP) are also known as standard temperature and pressure (STP). 

The International Union of Pure and Applied Chemistry (IUPAC) and the National Institute of Standards and Technology (NIST) are the two organisations that produce the most widely used standards, albeit these are not universally recognised as authoritative. 

Other organisations have produced a range of alternate definitions for their standard reference conditions, which can be found on their websites.

In chemistry, the International Union of Pure and Applied Chemistry (IUPAC) revised its definition of standard temperature and pressure in 1982:

From 1962 until 1982, a standard temperature of 273.15 K (32 °C) and an absolute pressure of exactly one atmosphere (atm) were used to define STP (101.325 kPa).

It has been described as having a temperature of 273.15 K (0 degrees Celsius, 32 degrees Fahrenheit) and an absolute pressure of exactly 105 Pa since 1982. (100 kPa, 1 bar).

STP should not be confused with the standard state, which is widely employed in thermodynamic evaluations of the Gibbs energy of a reaction to determine the Gibbs energy of the reaction.

Gay-pressure Lussac’s temperature law describes the relationship between the pressure and temperature of a gas in a closed system.

This law states that the pressure (P) of a fixed quantity of gas held at a constant volume is directionally proportional to the temperature (T) of the gas at that volume (T).

Because of this, as the pressure of a particular system increases, so does the temperature of that system, and the reverse is true as well. 

Gas laws describe the behaviour of gases in relation to their pressure, volume, temperature, and amount of a given gas. In the condition of matter known as gaseous state, gases are either compressed very tightly or expanded to fill a wide space.

Effect of catalyst

When a catalyst is used, it lowers the activation energy of the reaction, allowing it to proceed more quickly. 

In addition, the catalyst is recycled during the process.

It is only when the presence of a catalyst is present that certain reactions that would be thermodynamically beneficial in the absence of a catalyst occur at an acceptable rate.

Another reaction that falls into this category is catalytic hydrogenation, which is the process by which hydrogen is introduced across an alkene C=C bond to yield the saturated alkane result.

Catalysts are chemicals that improve the rate at which a reaction occurs by lowering the amount of activation energy required for the reaction to take place. 

In contrast to a catalyst, which is destroyed or modified during a reaction, a catalyst can be reused. 

For example, under normal circumstances, H2 and O2 do not combine.

Conclusion

All alkanes have a core carbon atom that is connected to four additional atoms, resulting in a saturated hydrocarbon (or groups). 

As a result of this saturation, the reactivity of alkanes is relatively low. 

Historically, saturated hydrocarbons were referred to as paraffins, which literally translated means little affinity. 

These alkanes, on the other hand, burn quite quickly. 

Combustion is defined as the reaction of alkanes with oxygen-producing heat to produce heat. 

Combustion is described as a chemical reaction with oxygen in which alkane is transformed into carbon dioxide and water with the emission of heat energy, according to the American Chemical Society.

It is possible to show the combustion of alkanes by using this equation for the combustion of methane.