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40 Terms

1

uses of methylated spirit

  • fuel

  • solvent

  • antiseptic

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2

why its better if less sulfur

  • sulfur reacts with oxygen to form sulfur dioxide

  • so less sulfur dioxide emitted

  • so les acid rain

  • so less limestone reacts with acid rain

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3

if cube x10 bigger surface area

surface area to volume ratio decreases by a factor of 10

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4

structure of DNA

  • two polymer chains

  • four different monomers

  • double helix

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5

if increase of ions on left side

  • equilibrium moves to the right

  • to the increase in concentration of ions is reduced

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6

if temp increas

  • equilbiurm moves to the left

  • so the temperature is reduced

  • therefore the forward reaction is exothermic

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7

why sometimes no change in equilibrium if pressure change

  • no change in equilibrium position

  • as no gases are present

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8

how to decrease rf value

  • allow to solvent front to travel further

  • use a different solvent

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9

how is ethanol produced from sugar solution

  • fermentation

  • add yeast

  • anaerobic conditions

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10

gas produced when sodium added to ethanol

  • hydrogen

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11

processes led to changes

  • volcanic activity released water vapour

  • condensed to form oceans

  • carbon dioxide dissolved in oceans

  • carbonates produce sediments

  • carbon locked up in sedimentary rocks

  • algae and green plants evolved

  • absorb carbon dioxide by photosynthesis which then released oxygen

  • carbon locked up in fossil fuels

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12

why is solution cloudly

  • sulfur formed

  • which is a precipitate

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13

investigate, connotation of sodium thiosulfate affects the rate of reaction

  • measure volume of sodium thiosulfate

  • place in conical flask

  • measure volume of hcl

  • place on cross

  • add hcl to flask

  • swirl

  • stop stopwatch

  • measure time for cross to become no longer visible

  • repeat and find mean

  • repeat for different concentrations of sodium

  • control

    • conc and volume of hcl

    • total volume of sodium thiosulfate solution

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14

evaluate suitability of polypropene and polyester

  • advantages of polyester

    • better flame resistance

    • higher melting point

    • absorbed water so less likely to ignite

  • disadvantages

    • high density, so heavy

    • absorbed water, gets wet and become heavy

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15

how carbon monoxide is produced when petrol is burned in car engines

  • incomplete combustion

  • as insufficient oxygen supply

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16

why max allow % of carbon monoxides has been decreases

  • greater public concern/ awareness

  • more cars so otherwise there would be more carbon monoxide entering atmosphee

  • improve engine technologu

  • catalytic converter have been introduced

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17

how oxides of nitrogen are produced when petrol is burned

  • nitrogen from atmosphere reacts with oxygen

  • at high temperature in engine, or with a spark from spark plug

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18

compare use of coated paper compared with polystryene to make disposable cups

  • raw materials

    • crude oil finite

    • wood renewable

    • wood involves land use and may involve deforestation

  • manufacturing

    • both required energy which may be derived from fossil fuels

    • paper more energy intensive

    • need for more energy for paper potentially release more carbon dioxide

    • paper involved higher water usage, so increase the potential for water pollution

    • paper cups heater to transport, so higher energy requirement

    • packaging requirements similar

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19

paper and polystyrene usage and disposal

  • usage

    • both single use, so neither has an advantage

  • disposal

    • paper release more energy if incinerated, so more energy can be used for other purposes

    • paper will decompose

    • polystyrene could resale toxins on incineration, and won’t decompose, but can be used to manufacture other products

    • both can cause litter or visual pollution

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20

titan has methane, ho this gg keeps titan warm

  • methane allows shorter wavelength radiation to pass through from the sun

  • which is re-emitted from the surface as longer wavelength radition

  • which is absorbed by methane in the atmosphere

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21

if no oxygen, why these organisms couldn’t have evolved in the same way as on earth

  • no oxygen

  • so photosynthesis hasn’t occured

  • so little carbon dioxide present,

    • oxygen using animals cannot have evolved on titan

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22

why don’t aluminium window frames corrode after they are made

  • aluminium has a coating og aluminium oxide

  • so the aluminium oxide protects the metal from further corrosion

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23

explain why diesel oil collects above heavy fuel oil but belo kerosene in the fractionating column

  • diesel oil has a lower boiling point than heavy fuel oil

  • but diesel oil has a higher boiling point than kerosene

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24

apparatus to find the rate of production of a gas

  • gas syringe

  • stopwatch

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25

three conclusions from graph

  • rate decreases

  • rate decreases more slowly as time increases

  • rate becomes zero at 60s

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26

magnesium over steel ships, how does this prevent steel from rusting

  • magnesium is more reactive than iron

  • so magnesium provides sacrificial protection

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27

explain the process by which carbon monoxide can be produced when methane is burned

  • not enough oxygen

  • so incomplete combustion

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28

what are glass fibres

  • a reinforcement

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29

why is an outer skin added to the polystyrene core

  • to make the thing

    • harder, stronger, tougher, more rigid, waterproof

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30

find total mass of dissolved solids in 100cm

  • weigh evaporating basin

  • add mesa volume of water

  • weight again

  • heat to evaporate water

  • reweigh

  • repeat heating until constant mass obtained

  • subtract mass of basin from mass

  • repeat and calculate a mean, discarding anomalous results

  • calculate the mass in 100cm3 water if necessary

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31

why don’t you put polymer with copper about tone melted

  • copper produced out be impure now

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32

why is recycled scrap better

  • uses less energy

  • conserve copper

  • produces less waste

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33

why did mass decrease

  • water vapour was produced

  • so water vapour escaped from the tube

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34

gass and bottles, LCA’S

  • manufacturing, glass is heavier so takes more energy to tranasport

  • use and operation, reuse of glass conserve resources, but consumes energy and water during washing

  • disposal, reduce use of landfill and use less energy than making new ones

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35

how does treatment of sewage work

  • screening/grit removal

  • sedimentation to produce sewage sludge and effluent

  • anaerobic digestion of sludge

  • aerobic biological treatment of effluent

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36

why aren’t ions stopped

  • ions pass through the filter

  • because the ions are in solution

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37

ground water,

  • contains microbes which are harmful

  • so the water is sterilised

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38

why is drinking water called pure

  • the water is unadulterated/in its natural state

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39

why only ammonia collected

  • mixture is cooled

  • so that only ammonia liquefies

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40

yield of caber process

  • higher temperature gives higher rate as more particles have the AE

  • use of catalyst gives higher rate because the AE is lowered

  • use of catalyst has no effect on the position of equilibrium

  • higher temperature, uses more energy so increases cost

  • higher pressure, required stronger reaction vessels so increases costs

  • catalyst reduces energy costs

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