organic chem (crude oil/hydrocarbons)

• crude oil and hydrocarbons
• crude oil is found in rocks it is a finite resource (if we carry on using it it will run out one day)
• crude oil is formed over millions of years ago by tiny sea creatures called plankton which are buried in mud
• crude oil is a mixture of molecules called hydrocarbons
• eg methane has one carbon atom covalently bonded to 4 hydrogen atoms
• hydrogen and carbon atoms are made up of hydrocarbons
• e.g. ethane is a hydrocarbon found in crude oil
• general formula for alkane is CnH2n+2
• to find out number of carbon atoms we times 2 then add 2
• ethane has 2 carbon atom covalently bonded to 6 hydrogen atoms
• methane has 1 carbon atoms and 4 hydrgogen atoms
• propane has 3 carbon atoms and 8 hydrogen atoms
• butane has 4 carbon atoms and 10 hydrgogen atoms
• methane ethane propane and butane are all alkanes
• saturated hydrocarbon means it has no double bonds
• there are 3 key properties we need to know in hydrocarbons
• 1. viscosity- tells us the thickness of a fluid fluids with a high viscosity flow slowly . As the size of hydrocarbon molecule increases the molecule gets more viscious. very short chain hydrocarbons flow very slow indeed
• 2. boiling point- a temp which a liquid turns into a gas. very short chin hydrocarbons have a very low boiling point . All the hydrocarbons here are gases at room temp. They our at lower room temp bcz they have low boiling points
• 3. flammability how easily a hydrocarbon combusts (burns)in air. short chain hydrocarbons are extremely inflammable. As the size of the hydrocarbon molecule increases the molecule becomes less inflammable in other words difficult to burn
• methane has a boilling point of -161
• ethane has boilling point of -89
• propane has a boiling point of -42
• butane has a boilling point of -1