Fuel: the Need of an Hour

Fuel is any material that stores energy that can later be extracted to perform mechanical work in a controlled manner. Most fuels used by humans undergo combustion, a redox reaction in which a combustible substance releases energy after it ignites and reacts with the oxygen in the air. Other processes used to convert fuel into energy include various other exothermic chemical reactionsand nuclear reactions, such as nuclear fission or nuclear fusion. Fuels are also used in the cells of organisms in a process known as cellular respiration, where organic molecules are oxidized to release usable energy. Hydrocarbons are by far the most common source of fuel used by humans, but many other substances, such as radioactive metals, are currently used as well .

Fuels are chemical substances which may be burned in oxygen to generate heat. They mainly consist of carbon and hydrogen and sometimes a small amount of sulfur or minerals. There are solid, liquid and gaseous fuels. Coal and Coke are examples of solid fuels. Petroleum oils are usually a mixture of several liquid fuels. Gaseous fuels may be a mixture of gases such as methane (CH4), ethane (C2H6) and so on. The components before the combustion process are called reactants. The combustion processproduces new components which are called products. E.g. combustion of 1 kmol of carbon with 1 kmol of pure oxygen will produce 1 kmol carbon dioxide:

What is Fuel? 

Fuel is any material that is burned or altered in order to obtain energy. Fuel releases its energy either through a chemical reaction means, such as combustion, or nuclear means, such as nuclear fissionor nuclear fusion. An important property of a useful fuel is that its energy can be stored to be released only when needed, and that the release is controlled in such a way that the energy can be harnesseud to produce work. 

All carbon-based life forms - from microorganisms to animals and humans - depend on and use fuelsas their source of energy. Their cells...