C9- crude oil and hydrocarbons ⛽️

• crude oil is a molecule of hydrocarbons, that was formed over millions of years, from the remains of ancient dead marine organisms.

• found in rocks, crude oil is a finite resource [meaning crude oil is used up at a faster rate, than it can be replaced]

• crude oil is formed over millions of years, from the remains of tiny sea creatures called plankton- which were buried in mud

• hydrocarbons, are molecules made up of hydrogen and carbon atoms only

• an alkane, is a saturated hydrocarbon with the general formula CnH2n+2

• CnH2n+2 • [you have to multiply the number of carbon atoms by two, and then add two]

• if the number of carbon atoms (n) is known, the number of hydrogen atoms can be calculated • this is done, by multiplying the number of carbon atoms by 2 and then adding 2

• CH4 [methane has one carbon atom and four atoms of hydrogen]

• C2 H6 [ethane has two carbon atoms, and six hydrogen atoms]

• C3 H8 [propane has three carbon atoms, and eight hydrogen atoms]

• C4 H10 [butane has four carbon atoms, and ten hydrogen atoms]

• alkanes are saturated molecules because in alkanes, the carbon atoms are fully bonded to the hydrogen atoms

• an example where hydrocarbons, are used as fuels are: • ships, planes and cars

• hydrocarbon fuels, release energy when combusted [burned].

• during combustion, the carbon and hydrogen atoms in the fuel will react with oxygen as become oxidised [the loss of electrons; the gain of oxygen]

• if the oxygen that the carbon and hydrogen atoms react with are unlimited, this reaction produces carbon dioxide and water. • this is because, the hydrocarbons completely combust

• viscosity- meaning the thickness of a fluid • flammability- meaning, how easily a hydrocarbon combusts [burns] • and, boiling points- the temperature at which a liquid turns to a gas

• viscosity, is the thickness of a fluid. [the resistance of a fluid to flow] • fluids with a high viscosity will flow slowly • ; as the size of the hydrocarbon molecules increase, the molecules get more viscous.

• because hydrocarbon molecules get more viscous, if the size of hydrocarbon molecules increase, long chain hydrocarbons such as butane are extremely viscous.

• short-chain hydrocarbons such as methane are extremely flammable • this is because, as the size of the hydrocarbon molecules increases, the molecules get less flammable • ; long chain hydrocarbons such as butane, are very difficult to burn.

• as the size of the hydrocarbon molecules increases, the boiling point also increases • this means, very long chain hydrocarbons such as butane, have very high boiling points

• because, the intermolecular forces bewteen alkanes become more significant, as the number of atoms and electrons in a molecule increase