Combined science

• The four fundamental forces of nature are gravity, electromagnetism, the strong nuclear force, and the weak nuclear force.
• Crude oil fractions from fractional distillation can be split into smaller molecules.this is called cracking.
• cracking is a thermal decomposition reaction. This means the molecules are broken down by heating them- this can be done by catalytic cracking or by stem cracking.
• Complete combustion occurs when there is plenty of oxygen available so that all the carbon in the fuel reacts with oxygen to form carbon dioxide (CO2)
• Incomplete combustion occurs when there isn't enough oxygen to burn all the fuel completely
• Cracking produces alkenes which have double bonds between carbon atoms
• Alkanes are saturated hydrocarbons with single covalent bonds between carbon atoms
• A hydrocarbon is any compound made up only of hydrogen and carbon atoms. They are found in crude oils and natural gas.
• Sulphur dioxide (SO2) is formed if sulfur is present in the fuel. It is released into the atmosphere where it forms acid rain
• Nitrogen oxides (NOx) are also produced during combustion. They contribute to air pollution and smog
• The general formula for an alkene is CnH2n
• Aldehydes contain a carbonyl group (-CHO) at the end of their chain
• Crude oil is formed from the remains of dead plants and animals over millions of years under high pressure and temperature deep underground. It contains many different types of hydrocarbons, including paraffin waxes, alkanes and cycloalkanes.
• Crude oil is a mixture of lots of different hydrocarbons, most of which are alkanes. the different compounds include oil are separated by fractional distillation.
• Crude oil is a fossil fuel found in rocks.
• Hydrocarbons-

  •methane CH4

  •Ethane C2Hs

  •propane C3H8

  •Butane C4H10

  
• complete combustion occurs when there is plenty of oxygen