paper2 dk Flashcards

1
Q

how is the operating temp kept low

A

cryolite

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2
Q

why lid on chromatogram

A

loss/evaporation of solvent
toxic fumes

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3
Q

uses of nitrogen

A

aircraft tyres
light bulbs
food packaging

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4
Q

CaCl2

A

slightly soluble

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5
Q

2 problems with acid rain

A

limestone corrodes
vegetation dies

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6
Q

blast furnance raw materials

A

coke
limestone

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7
Q

haematite

A

iron oxide

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8
Q

limestone

A

calcium carbonate

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9
Q

molten substance

A

slag

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10
Q

4 reasons for cracking

A
  • greater supply of long chain
  • higher demand for short chain
  • alkenes make polymers
  • short chain burn more cleanly/easily
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11
Q

monomer

A

molecule used to make a polymer

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12
Q

gas thats 1% of dry air

A

argon

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13
Q

2 observations when magnesium reacts with oxygen

A

bright white light
white solid formed

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14
Q

appearance of iron after a week

A

brown

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15
Q

why use a burete

A

more precise
avoids refill

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16
Q

why is mass of CO2 less than expected

A

CO2 dissolves in acid

17
Q

why cant use passing over iron filings for CO2

A

% of CO2 in ir is too small ( less than 1cm3)

18
Q

molecular formula of ethanol

A

C2H6O

19
Q

hydration of ethene +/-

A

+ fast
+ higher yield
+ no land to grow
+ continuous
- non renewable
- high operating temp/pressure
- phosphuric acid is harmful

20
Q

crude oil vs kerosene

A
  • crude oil is a mixture of molecule sizes
  • both have covalent bonds
  • more bonds in crude oil
  • kerosene is less viscous
21
Q

catalyst for ethanol dehydration

A

Al2O3

22
Q

why students value differs from data book value for enthalpy change

A

heat lost to surroundings
KOH dissolves slowly

23
Q

kerosene use

A

plane fuel

24
Q

why is a boiling tube not directly heated with a bunsen

A

would be heated too quick
flammable

25
Q

why using not dry sodium chloride could cause explosions

A

water +sodium makes hydrogen

26
Q

why sodium wasnt discovered till 1807

A

electricity not discovered - csnt do electrolysis

27
Q

chemical test for ethanoic acid

A

add metal eg Mg
effervescence
test gas with lit splint - squeaky pop

28
Q

trace gas with highest % in unpolluted air

A

argon

29
Q

why fermentation is done with no air

A

anaerobic conditions
normal respiration doesnt make ethanol

30
Q

CH3CH2COOCH3

A

methyl propanoate

31
Q

why chlorine added to water

A

to disinfect