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Crude oil (petroleum) - made from plankton that changed gradually over millions of years. Supplies of crude oil are finite

- less accessible - trickier to extract

- resources become rarer

Uses - hydrocarbons - consist of H and C atoms only - different chain lengths

LPG, petrol, napthel, kerosene, diesel, fuel oil, bitumen (gases - liquid - bitumen)

Weak intermolecular forces are easily overcome by higher temperat

ures as there is enough energy for them to overcome the forces between molecules.

Larger chains have stronger intermolecular forces so higher temperatures are needed due to the increased amount of energy needed as they have a higher boiling point.

If crude oil comes in contact with birds feathers - it will get ingested and when trying to preen, it can cause death.

Oil slicks can ***** natural oil from the feathers - lose the ability to be waterpoof and warm.

Cracking always produces a shorter chain alkane and alkene

- converts large alkane molecules into smaller alkane and alkene molecules

- makes useful alkane molecules becase they can be used to produce polymers

- helps an oil refinary to match its supply of useful products such as petrol.

Methane - alkane - single covalent bond - single bond shared pair of electron                                 saturated - single C - C bond

Displayed formula   Molecular formula                        

     H

H - C - H                        CH4

     H

Ethene - alkene - double covalent bond - double bond shared pair of electron                      unsaturated - C = C bond

Fuel - reacts with oxygen to release fuel energy

These are the factors needed to bear in mind when choosing the best fuel to use

Toxicity

Energy value

Availability

Cost

Useability

Pollution

Storage

The method to remember these is by this acronym - TEACUPS

Calculate energy supplied by 100g of water by heating it by 300 degrees celcius.

E = m.shc.change in temperature

This formula is used to calculate the amount of energy released in a reaction

Energy released per gram = energy released / mass of fuel burned

- anhydrous copper sulfate - white to blue proving that water is present

- limewater - colourless to cloudy proving that carbon dioxide is present

The products of complete combustion is CO2 and water

methane + oxygen --> carbon dioxide + water             CH4 + 202 --> CO2 + 2H20

The advantage of complete combustion - less soot made - more heat energy - no poisonous gases

Incomplete combustion

Propane + oxygen --> carbon monoxide + water         C3H8 + 3.5O2 --> 3CO + 4H20

                                         Yellow                       Blue

Air hole                             Closed                       Open

Effect on pot                       Soot                          No soot

Heat energy released          Less                          More

Products                         CO2, CO, C                 CO2 only

Combustion                     Incomplete                  Complete

Rise in CO2 - deforestation

- less trees to use up CO2 by photosynthesis

- burning off stumps and debris adds to CO2 in the atmosphere

- increased population

- degassing of early volanoes produced an atmosphere rich in water vapour and CO2

- % of water vapour was reduced due to it being condensed to form oceans

- % of CO2 reduced due to it being dissolved in the ocean waters

- % of N2 increased as it is a stable unreactive gas

- % of oxygen increased due to photosynthesis

CO (carbon monoxide) - a product of incomplete combustion of petrol or diesel

NO (nitrogen oxides) - formed in in the engine, incomplete combustion

SO2 (sulfur dioxide) - sulfur impurities in fossil fuels burn to produce sulfur dioxide

N2 from the air combines with the O2 from the air at high temperatures fond in the car engines

N2 + O2 --> 2NO

Catalytic Converter - a device incorporated in the exhaust system of a motor vehicle, containing a catalyst for converting pollutant gases into less harmful ones.

2CO + 2NO --> 2CO2 + N2

Alkenes discolourise bromine water. Bromine water goes from orange to colourless

Conditions needed for polymerisation - high pressure and a catalyst

Item                                     Polymer                                      Properties

Cup                             Expanded polystyrene                 Low density, heat insulator

Climbing rope                          Nylon                                Strong in tension, flexible

Bed linen                            Polyester               Stretched to make – tiny fibres , can be dyed

Guttering                                PVC                          Moulded into shape + waterproof

Bullet proof vest                     Kevlar                                        Strong, tough

Plastics that have weak intermolecular forces between polymer molecules have low melting points - stretched easily as the molecules can slide over each other

Plastics that have strong forces between polymer molecules are called cross link bridges             - these plastics have high melting points - cannot be stretched & are rigid - the chains cannot slide over one another

Disposal of plastics

Plastics like polyethene are very unreactive and take 100s of years to decompose - take up valuable land in landfill sites

+ incineration is good because it reduces the bulk that goes into landfill sites and it also makes useful heat energy

- bad because it wastes resources and can make toxic gases

Recycling plastics saves raw materials - difficult as plastics are tricky to sort

Properties of nylon:

Adv - tough, lightweight, keeps water out, keeps UV light out.

Disadv - doesnt allow water vapour through - sweat condenses - not breathable

Uses of nylon:

Nylon is popular for hoisery and is used to make track pants, shorts, swimwear, active wear, windbreakers, bedspreads, and draperies. It can also be made into parachutes, flak vest, combat uniforms, tires and life vests.

Breathable:

It allows water vapour out but doesnt allow water in - sweat doesnt condense on the skin.         This is great for active outdoor people because:                                                                      - condensed sweat makes you feel damp and uncomfortable                                                    - if sweat cant evaporate, you cant cool down when exercising                                               -you quickly get cold if your sweat condenses when you stop exercising in cold conditions                                                 

The structure of Gore-Tex

• Gore -tex: nylon laminated with PTFE / polyurethane membrane & an inner comfort layer
  
• Holes in PTFE are too small for water to pass through but big enough for water vapour to pass
• The nylon is needed to protect the very fragile PTFE laminate

Cooking is a chemical reaction because

• new products are made
• irreverible reaction

Denaturing

When egg or meat is cooked, protein molecules change shape. This is denaturing. They unravel and join in a 3D structure.It changes the texture of the egg.

Cooking potatoes

Cooked potatoes  - easier to digest

cell walls rupture - loss of rigid structure - softer texture

Starch grains isnide swell up & spread out and many escape from the cell

An emulsifier molecule has a:

• Hyrdrophilic head - bonds with water molecules
• Hydrophobic tail - bonds with oil molecules

Therefore the water and oil droplets become unable to separate out - emulsionEmulsions

Mayonnaise and salad cream are emulsions but there are others too, for example

• Butter - fat and water
• Milk - water and fat

Baking Powder

sodium hydrogencarbonate --> sodium carbonate + water +carbon dioxide

2NaHCO3 --> Na2CO3+H20+CO2

Esterification Reaction

alcohol + organic acid --> ester +water

Desirable physical property:

• Evaporates easily - particles must reach nose easily
• Non toxic - msut not poison the user or make them ill
• Does not react with water - unreactive with perspiration
• Does not irritate the skin - shouldn't cause harm
• Insoluble in water - msut not be washed off easily

Volatiility of esters

• in oredr to evaporate - sufficient energy needed o overcome attraxtion to other molecules in the liquid
• Only weak attractions exist between particles so it is easy to overcome the attraction

• Solute - a solid which will dissolve
• Solvent - a liquid in which a solue dissolves
• Solution - a solute dissolves in a solvent
• Soluble - it will dissolve
• Insoluble - it will not not dissolve

Nail varnish will not dissolve in water

• Strong attractions between varnish molecules and other varnish molecules
• Strong attractions between water molecules and other water molecules
• Only weak attractions between varnish molecules and water molecules

Water will not dissolve nail varnish colours because:

• the attraction between water molecules is stronger than the attraction between water molecules and particles in anil varnish
• the attracts between particles in nail varnish is stronger than the attraction between water molecules and particles in nail varnish

Why is cosmetics testing on animals banned in the EU?

• It is considered cruel to the animal
• There are plenty of cosmetic ingredients to use that have already been tested on animals in the past
• There are alternatives to testing on animals; artifical skin, tissue culture, computer modelling, testing on humans

Advantages                                                                                                         

• to check a cosmetic is safe before using on humans    
• so humas don't get harmed
• animal skin is a close approximation for human skin

Disadvantages

• the view that animals have moral rights
• animals might suffer
• animal skin may not be a perfect match for human skin

Milk

• colloid - where paricles are mixed and dispersed with particles of a liquid but are not dissolved
• the particles of one liquid (butterfat) are mixed and dispersed with particles of anotther liquid (water) but are not dissolved
• Particles dont separate as they are scattered or dispersed through the liquid and are so small they dont settle

Emulsion Paint

• solvent - usually water - evaporates as paint dries - washes under a tap (brushes)
• pigment - tiny solid particles of colour - dispersed as a colloid - white pigment - titanium dioxide
• binder - vinyl acetate (PVA monomer) dispersed as a colloid - forms hardwearing coating by polymerisaiton - trapping pigment in a layer

Uses - interial or exterial walls

• Solvent - e.g. an aliphatic petroleum solvent, an ester - evaporates as paint dries
• pigment - tiny solid paricles of colour - dispersed as a colloid - white pigment - titnaum dioxide
• binder - e.g. an alkyd resin - dispersed as a colloid. forms hardwearing coating by reaction with oxygen in the air, forming a 3D cross linked structure

the solvent is an ester so brushes must be cleaned using a solvent liek white spirit not water

Making more colours

Acrylic paints added to thermochromic pigmetns to make more colour changes

Phosphorescent pigments

These absord energy in the daytime - release at night

Modern watches use phosphorescent paints - much safer than radoactive substances but have a limited brightness time