Making crude oil useful
Fossil fuels are a finite resource because they are no longer being made or very slowly
Fossil fuels are being used up faster than being made=non-renewable resource
Hydrocarbon: a molecule made up of carbon+hydrogen atoms only
Crude oil can be seperated because hydrocarbons in different fractions have differently sized molecules...Large molecules have strong froces of attraction, a lot of energy is needed to break the forces, these fractions have high boiling points,
Forces between molecules are called INTERMOLECULAR FORCES
Oil slicks can damage birds feathers causing death, and the clean up operations can use detergents that damage wildlife.
A political problem with oil is unstable oil producing countries can set high prices for oil and cause problems for non oil producing countries.
Cracking is a process that turns large alkane molecules into smaller alkane and alkene molecules
Alkenes are useful for making polymers
Using Carbon Fuels
Word equation for complete combustion: methane+oxygen-->carbon dioxide+water
Complete combustion occurs when a fuel burns in plenty of oxygen
Advantages of complete combustion:
- More energy is realesed
- Carbon monoxide and soot are made incomplete combustion
Equation for incomplete combustion: fuel+oxygen-->carbon monoxide+ water
Balanced symbol equations;
Clean air is made up of 78% nitrogen, 21% oxygen, 0.035% carbon dioxide
The atomosphere: Gases escaping from the interior of the earth formed the orginal atmosphere, then plants that could photosynthhesise removed carbon dioxide and added oxygen.
Degassing-the process in which gases come from the centre of the earth through volcanoes
1 theory about the atmosphere:
The atmosphere was once orginally rich in water vapour and carbon dioxide, this vapour condensed to form oceans and the carbon dioxide dissolved in the water. The % of nitrogen increased, being unreactive, little was removed. Organisms that photsynthesised evolved, so the % of carbon dioixde decreased and oxygen increased.
Sulfur dioxide is a pollutant that causes difficulty for people with asthma , dissolves in water to form acid rain too, causing damage to wildlife and limestone buildings
A catalytic converter gets fitted into cars, they convert carbon monoxide into carbon dioxide. The reaction: Nitric oxide and carbon monoxide react on the surface of the catalyst, the natural components formed are, carbon dioxide and nitrogen
Hydrocarbon: a molecule made up of hydrogen and carbon atoms only.
Alkane:hydrocarbon with single covalent bonds only Alkene:hydrocarbon that has a double covalent bond
Propene:alkene Propane:alkane also a monomer Poly(propene)=polymer
Bromine(normally orange) is used to test for an alkene, it decolourises when added to an alkene, the bromine water and alkene form a new compound by an addition reaction=DIBROMO COMPOUND!
Saturated: Only single covalent bonds between cabon atoms
Unsaturated: At least one double bond between carbon atoms
- Process in which many alkene monomers reacts to give a polymer
- Conditions for this reaction: a catalyst and high pressure
- A long chain is made until the reaction is stopped
- The reaction causes the double bond in the monomer to break and each of the carbon atoms form new bonds
Nylon:Lightweight, waterproof and keeps UV out, doesnt let sweat out.
GORE-TEX has all the same properties but is also breathable! It is made from PTFE membrane, the hole in PTFE are too small for water to pass thorough but big enough for water vapour to pass through, it is laminated onto nylon to produce a stronger fabric.
Scientists are developing new polymers:
- Boidegradable polymers
- Polymers that dissolve
Problems with exsisting polymers: Disposal of non-biodegradable polymers means landfill gets full quickly, land fill means wasting land that could be useful, burning plastics make toxic gases, waste crude oil used to make polymers, difficult to sort out the different polymers
Stretchy Polymers: plastics with weak intermolecular forces between molecules, so have low melting points, and can be stretched easily as polymer molecules can slide over each other
Rigid Polymers: strong intermolecular forces between molecules, high melting points and dont stretch, rigid!
Cooking and Food Additives
Protein molecules permanently change shape when cooked=denaturing
The texture also changes because the shape of protein molecules change shape.
Potatos are easier to digest when cooked because: Starch grains swell and spread out, the cell walls rupture resulting in the loss of their rigid structure and a softer texture is produced
Baking powder-sodium hydrogencarbonate
When it is heated it decomposes to give off carbon dioxide
sodium hydrogencarbonate-->sodium carbonate+carbon dioxide+water
Emulsifiers-molecules that have a water loving part(hydrophilic)and a oil/fat loving part(hydrophobic)
The hydrophobic end goes into the fat droplet!
- Emulsifiers help to keep oil and water from seperating
- The hydrophilic end bonds to the water molecules
- The hydrophobic end bonds with the oil molecules
- The hydrophilic end is attracted to the water molecules which surround the oil, keeping them together
Alcohol+acid-->ester+water..............Esters are used to make perfumes! An ester experiment:
The acid is added to the alcohol and heated for some time, the condenser stops the gas from escaping and cool it down again so it can react more, the condenser allows the reaction to go on for longer.
Evaporate easily=perfume particles can reach the nose, be non toxic, not react with water=no reaction with perspiration, not irritate the skin=perfume can be put directly on skin, be insoluble in water=cannot be washed off easily.
Solutions-a mixture of a solvent and solute that does not seperate out, ester can be used as solvents
Particles-volitality, or ease of evaporation of perfume can be explained in terms of kinetic theory
In order to evaporate, liquid particles need sufficient kinetic energy to overcome force of attraction to other molecules in a liquid. Only weak attractions exist between particles of the liquid perfume so it's easy to overcome these attractions as there is sufficient kinetic energy.
Water will not dissolve nail varnish:
The attraction between water molecules and the attraction between the nail varnish molecules is stronger than the attraction between the water and nail varnish molecules
Paints and Pigments
Paint is a colloid where the particle are mixed and dispersed with particles of a binding medium but are not dissolved, the components in a colloid wont seperate because the particles are dispersed throughout the mixture and are sufficiently small so wont settle at the bottom.
Paints dry becasue: they are applied in thin layers+the solvent evaporates
Emulsion paints-water based that dry when solvent evaporates
Oil paints-the solvent evaporates, the oil is oxidised by atmospheric oxygen
Thermochromic pigments-change colour at different tempratures
- Thermometers becasue they change colour when the temperature of a body rises
- Some cups, to show they are hot
- Electric kettles-safety
- Babies spoons and bath toys-too hot for baby
Acrylic+thermochromic make even more colour changes! Yellow acrylic paint+blue thermochromic paint(cool)-->green mixture(cool)--heat--->yellow(hot)
Phosphorescent Pigments-glow in the dark because they absorb and store energy, then realese it as light slowly! Better and safer than radioactive paints that were previously used