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30 Cards in this Set
- Front
- Back
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what are fossil fuels made of
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remains of dead plant material
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why does fractional distillation work?
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large hydrocarbons have high bp and small have low
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what are alkanes
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saturated hydrocarbons
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what is the rule foe alkane hydrogen and carbon relationship
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2n + 2
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what are alkenes
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unsaturated hydrocarbons e.g. have a c=c
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what is the general formula for alkenes
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2n
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why do we carry out cracking
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large hydrocarbons are not in high demand
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what do we need for cracking
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hot temperature and a catalyst
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what is another name for an addition reaction of alkenes
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hydrogenation
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how can you distinguish between alkanes and alkenes
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alkenes are moee reactive. bromine water
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how do you make polymers
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heat alkenes at a high temperature and the monomers join together
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what are the main categories of plastics
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thermosoftening- plastics with weak intermolecular forces between their polymer chains. low mp and slide over eachother
thermosetting- plastics with links between the polymer chains (cross linking) makes it more brittle, harder, higher mp |
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what is goretex
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pores for sweat to pass out but not water to pass in
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what is the concebtration of the following gases: oxygen, nitrogen, co2
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21% 78% 0.035%
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what was the evolution of the atmosphere
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1) co2 in the atmosphere from volcanoes
2) co2 dissolves into seawater abd aquatic plants grow releasing o2 3) atmosphere forms n+ due to unreactiveness |
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what do internal combustion engines do?
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nitogen + oxygen -> nitrates
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so4 leads to.. co2 leads to.. cfc's lead to.. nitrates lead to.. |
acid rain, greenhouse effect, ozone depletion, photochemical smog |
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what do catalytic converters do?
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co-> co2 by.. 2co + 2no > n2 + 2co2
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why are potatoes easier to digest when cooked
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cell wall of cellulose breaks down abd starch grains swell and can be digested more easily
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emulsifiers such as lecithin have..
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hydrophilic heads and hydrophobic tails
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sodium hydrogen carbonate thermally decomposes to form
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sodium carbonate. water and co2
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name categories of food additives
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antioxidant, flavour enhancers, colouring, emulsifiers
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how do you make esters
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acid + alcohol + catalyst > ester + water
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what are properties of esters
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volatile, non toxic, unreactive, insoluble
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colloid
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particles mixes abd dispersed in liquid but wont separate out
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how do paints dry?
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1) thin layer
2) solvent evaporates 3) polymer skin |
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how do emulsion paints dry
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water based. 2 colloid
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how do oil paints dry?
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solvent (hydrocarbon) polymerises and oxidises -> varnish
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thermochromic paints
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change colour according to heat
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how do phosphorescent pigments work?
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absorb and store light and release over a period of time
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