C1

How fractional distilation works

Fractionating column has a temp gradient which is colder at top and hotter at bottom

Low boiling point leaves at top and vice versa

Cracking

Hydrocarbons are alkanes/alkenese, Large alkanes can be broken into alkenes and alkanes - needs catalst high temp and high pressure. Also alkane molecules can be used to make polymers. Cracking can change crude oil into petrol.

Forces between molecules

Hydrocarbon - stron covalent bond between atoms in the molecule and weak intermolecular forces (forces of attraction between molecules). When a liquid hydrocarbon is boiled, molecules move fast until intermolecular forces are broke --> gas. Small molecules of weak forces of attraction.It's difference in boiling point that allows seperation of hydrocarbons

Complete combustion of a hydrocarbon

CH₄ + O₂    →    CO₂ + H₂O

Incomplete comustion

2CH4 + 3O2 -> 2CO + 4H20 If little oxeygen is present replace 2CO with C (soot)

Limewater turns milky of CO2 is present

Atmosphere today
78% N 
21% O
Changing levels of gases - theory
1) Hot volcanic earth released gas from earth to atmosphere - Ammonia CO2 water vapour
2)Earth cooled surface below 100 water vapour into water oceans released CO2 by dissolving gas
3)Levels of nitrogen in atmos increased - nitrifying bacteria
4)Level of oxeygen increased with development of plants that could photosynthesise
Air Pollution
Sulfure dioxide - pollution - acid rain - kills plants errodes stuff 
Reducing pollution
Carbon monoxide can be converted to CO2 by a catalytic converter:
carbon monoxide + nitrogen oxide → nitrogen + carbon dioxide
2CO + 2NO → N₂ + 2CO₂

Hydrocarbons
Carbon atoms make 4 each hydrogen make one each when a hydrocarbon is made, carbon atoms share  a pair of electrons to make a covalent bond.
Alkanes
Hydrocarbon with one covalent bond is an alkanes, call carbon atoms make 4 single covalent bonds, main chain will have one C-C bond.Alkanes that have 1 covalent bond are saturated
Alkenes
Hydrocarbon with one or more double C-C bond - alkene. Double bonds have two shared pairs of electrons. Alkenes have at least 1 double covalent bond so the c atom isn't bonded to max h atoms - unsaturated
Test for alkenes
Alkenes decolourise bromine water and alkanes have no effect - test for unsaturation.
Polymerisation
Alkenes made in cracking are small molecules that can be used as monomers. Double bonds in alkenes easily broken so monomers can join to make poymers. Molecules in plastic = polymers. When alkenes join together to make a polymer - polemerisation needing high pressure and catalyst. Polymerisation involves the reaction of many unsaturated monomer molecules to form a saturated polymer

Different polymers have different structure and properties.
Polyethene - light,flexible,easily moulded,can be printed on,uses-plastic bags, moulded containers
Polystyrene - light, poor conductor of heat - Uses - Insulation (poor conductor of heat)
Polyester - light, waterproof, tough, can be coloured, uses - clothing + bottles
Structure of plastics
Polymers like PVC are tangled long chain molecules held together by strong covalent bonds
Plastics that have weak intermolecular forces have low melting points and can be stretched and vice versa.
Nylon
Light, tough, waterproof, blocks UV good for outdoor clothing
Gore-tex
breathable material made from nylong has good things from nylon but treated to allow sweat to escape and not rain. Nylon fibers coated with membrane of polyurethene makes holes in fabric smaller.
Disposing of polymers
3 choices - landfill(Non biodegradabled), burning (bad cause pollution), recycling (expensive)

Cooking food
Protein denatures (Irreversible) and changes shape when heated which causes changes (obvious)
Potatoes cooked soften (obvious)
Potatoes and other vegetables have rigid cell wall which during cooking is softened and starch grains swell up and release - consumed by body. 
Baking poweder
Baking powder as sodium h carbonate when it's heated it decomposes to give sodium carbonate, h20 + c02 in equation:2NaHCO₃ → Na₂CO₃ + CO₂ + H₂O
Limewater can be used to test for CO2, if CO2 is present limewater goes from colourless to milky.
Additives
Antioxidants (stops food reacting with oxeygen + shelf life) Food colours (duh)
Flavour enhancers (doesn't add it's own taste) Emulsifiers (help oil and water mix)
Emulsifiers
Molecules have hydrophilic and hydrophobic end and both droplets are mixed together, hydrophilic attracts water and hydrophobic attracts oil, attraction holds oil and water together.

Perfumes
Esters often used as perfumes, made by reacting alcohol with organic acid to make ester + H20
Properties of perfum
Evaporate easily, not toxicm not irritate, not dissolve in water, not react with water
Obvious advantages - reach nose + not come off on skin
Testing perfumes
Animal testing - mostly bad - obvious
Solvents
Nail varnish won't dissolve in water because:
Attraction in water molecules stronger than attraction between water molecules and nail varnish molecules combined
Vice Versa.

Paint is a colloid (made of small particles that mix well - disperse but not disolve with liquid)
Paint is a mixture of pigment (colour) binding medium (oil sticks to pigment + surface) and solvent (thins thick binding medium - easier to coat surface)
Solvent in emulsion paint is water. In oil based paints, pigment is dispersed into oil often solvent present that dissolves the oil.
The particles size of soilds in colloid must be small - spread across mixture - if they are too big they gather at the bottom of it.
Oil based paint dries in 2 ways - solvent evaporates or oil binding medium reacts with O2 and dries to form hard layer.
Special pigments
Thermochronic pigments change colour when heated. Used for trivial things.
Phospherescent pigments glow in dark.