GASOLINE-PETROL

WHAT IS PETROL AND HOW IT WORKS
Gasoline or petrol is a petroleum-derived liquid mixture consisting mostly of aliphatic hydrocarbons and enhanced with aromatic hydrocarbons toluene, benzene or iso-octane to increase octane ratings, primarily used as fuel in internal combustion engines. Most Commonwealth countries or former Commonwealth countries, with the exception of Canada, use the term "petrol" (abbreviated from petroleum spirit). The term "gasoline" is commonly used in North America where it is often shortened in colloquial usage to "gas". This should be distinguished in usage from genuinely gaseous fuels used in internal combustion engines such as liquified petroleum gas (which is stored pressurised as a liquid but is allowed to return naturally to a gaseous state before combustion). The term mogas, short for motor gasoline, distinguishes automobile fuel from aviation gasoline, or avgas. The word "gasoline" can also be used in British English to refer to a different petroleum derivative historically used in lamps; however, this use is now uncommon.

What is gasoline?

Gasoline is known as an aliphatic hydrocarbon. In other words, gasoline is made up of molecules composed of nothing but hydrogen and carbon arranged in chains. Gasoline molecules have from seven to 11 carbons in each chain. Here are some common configurations:

     H H H H H H H
       
 H-C-C-C-C-C-C-C-H         Heptane
       
   H H H H H H H


   H H H H H H H H
        
 H-C-C-C-C-C-C-C-C-H       Octane
        
   H H H H H H H H


   H H H H H H H H H
         
 H-C-C-C-C-C-C-C-C-C-H     Nonane
         
   H H H H H H H H H


   H H H H H H H H H H
          
 H-C-C-C-C-C-C-C-C-C-C-H   Decane
          
   H H H H H H H H H H

Typical molecules found in gasoline

When you burn gasoline under ideal conditions, with plenty of oxygen, you get carbon dioxide (from the carbon atoms in gasoline), water (from the hydrogen atoms) and lots of heat. A gallon of gasoline contains about 132x10⁶ joules of energy, which is equivalent to 125,000 BTU or 36,650 watt-hours:

• If you took a 1,500-watt space heater and left it on full blast for a full 24-hour day, that's about how much heat is in a gallon of gas.

• If it were possible for human beings to digest gasoline, a gallon would contain about 31,000 food calories -- the energy in a gallon of gasoline is equivalent to the energy in about 110 McDonalds hamburgers!

EXAMPLE

CAR OF THE YEAR2007