CHEMISTRY Flashcards

1
Q

what happens in electrolysis?

A

requires a liquid to conduct electricity

Positive ions move towards negative electrodes

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2
Q

what does electrolysis extract? and what does it do and what is required?

A

metals more reactive than carbon.
makes it pure
high temperature & energy

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3
Q

what are the advantages of quarrying?

A
  • used as building materials
  • limestone products from thermal decomposition used to neutralise soils
  • used in power station chimneys to neutralise sulphur dioxide
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4
Q

what are the disadvantages of quarrying?

A
  • permanently changes the landscape

- noise and dust pollution

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5
Q

what other 2 methods could we use to extract small bits of copper?

A

low grade ores - bioleaching and phytomining

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6
Q

how does bioleaching work?

A

bacteria gets energy from bond between copper and sulfur separating out the copper. Leachate is produced containing copper and extracted by filtering

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7
Q

how does phytomining work?

A

low grade ore
grow plants in soil containing copper, builds up in leaves, plants harvested and burnt in a furnace, copper collected from ash.

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8
Q

where is crude oil from?

A

buried remains of plants and animals

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9
Q

advantages of crude oil?

A

good fuels for transport
reliable
cheap

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10
Q

what are the disadvantages of crude oil?

A

non-renewable
oil spills- birds poisoned
causes global warming and acid rain

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11
Q

what are 3 alternatives fuels for crude oil?

A

ethanol
biodiesel
hydrogen gas

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12
Q

how is ethanol produced?

A

produced from plant material made by the fermentation of plants

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13
Q

what are the pros of the alternative fuel of ethanol?

A

carbon neutral and it’s only other product is water - no pollution

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14
Q

what are the cons of ethanol fuel?

A

engines need to be converted and isn’t widely available

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15
Q

how is the alternative fuel biodiesel produced?

A

by vegetable oils & rapseed oils

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16
Q

what are the pros and cons of biodiesel?

A

carbon neutral, produces less sulphur dioxide & engines don’t need to be converted

expensive

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17
Q

how is hydrogen gas produced?

A

electrolysis of water

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18
Q

what are the pros of hydrogen gas?

A

very clean only forms water

need special expensive equipment & isn’t widely available

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19
Q

what is cracking?

A

long chain molecules like diesel into short chain molecules like petrol paraffin and ethene

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20
Q

what type of reaction is cracking?

A

thermal decomposition

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21
Q

what are the conditions needed for cracking? what are the products?

A

high temperature to vaporise it then passed over a catalyst. produces alkenes

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22
Q

what is polymerisation?

A

joining lots of alkenes together

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23
Q

how do you convert ethene to ethanol? pros, cons?

A

hydrated with steam in presence of a catalyst.
cheap
ethene is produced from a non renewable resource

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24
Q

how else could you get ethanol but from renewable resources?

A

fermentation - sugar (from plants) = carbon dioxide + ethanol

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25
Q

how do you get oils from plants?

A

plant material is crushed, then you press the crushed plant and squash the oil out.

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26
Q

what are the uses of extracting oils from plants?

A

provides humans energy, high boiling point than water - cook foods faster, rapeseed oil turned into biodiesel

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27
Q

why would you use the method hydrogenating on oils?

A

most are runny at room temperature - not useful

28
Q

how is the process of hardening: hydrogenating done?

A

reacted with hydrogen in the presence of a nickel catalyst at 60c - makes them saturated

29
Q

what 3 things does recycling metals do?

A

saves energy
saves natural resources
less pollution

30
Q

what type of fats are less healthy?

A

saturated

31
Q

what uses do polymers have?

A

plastic bags

memory foams for beds - smart polymers

32
Q

what are the pros and cons of polymers?

A

cheap

nonbiogradable, from crude oil and its non-renewable so prices will rise.

33
Q

what are the transition metals

A

ones in the middles

34
Q

what are the symbols for calcium hydroxide?

A

Ca(OH)2

35
Q

how is calcium hydroxide formed?

A

adding water to calcium oxide

36
Q

why might iron be converted to steel?

A

iron is brittle

steel is strong / flexible

37
Q

what is limestone heated in?

A

rotary lime kiln

38
Q

what products are formed from adding water and sand to limestone?

A

cement or mortar

39
Q

if you then add crushed rocks?

A

concrete

40
Q

metals unreactive are found in their?

A

native state, most are found as metal ores and need to extracted

41
Q

what is alloying?

A

adding small amounts to other elements - can improve properties as now has a irregular structure

42
Q

what is crude oil a mixture of?

A

hydrogen and carbon

43
Q

gases in the air can?

A

be separated from

fractional distillation for use in industry.

44
Q

what does the earths atmosphere consist of?

A

nitrogen 80%
oxygen 20%
co2 0.037%
other gases 0.9%

45
Q

in a emulsifier is the tail hydrophilic? what is it attracted to?

A

YES

attracted to WATER

46
Q

name the order of the alkenes?

A

methane - CH4
Ethane
propane
butane

47
Q

what properties does a shorter molecule have?

A

the less viscous it is - more runny
more volatile - turn into gas at lower temperature
more flammable

48
Q

what is complete combustion

A

all the fuels burn

49
Q

what is formed from partial combustion

A

solid particulates of soot & carbon monoxide

50
Q

what causes global dimming

A

soot & ash - reflect sunlight back

51
Q

what do you get when you add a LOT of water to slaked calcium hydroxide?

A

calcium hydroxide solution - limewater

52
Q

what can limewater be tested for?

A

carbon dioxide- if it’s present so is limestone - bringing it back to the start of the calcium carbonate

53
Q

what is the core of earth made out of?

A

iron and nickel

54
Q

what was in the earths early atmosphere?

A

volcanoes added lots of c02 water and nitrogen
cooled and condensed into the oceans
plants appeared and photosynthesised to absorb the c02 and release oxygen

55
Q

how would you test for an unsaturated hydrocarbon?

A

add bromine water, will turn from orange to colourless

56
Q

what makes unsaturated hydrocarbons?

A

cracking

57
Q

what makes saturated hydrocarbons?

A

crude oil from fractional distillation

58
Q

when metal carbonates react with acids what is formed?

A

salt water and carbon dioxide

59
Q

how is iron removed from its ore?

A

mix iron oxide and carbon in a blast furnace- reduction of carbon
carbon displaces the iron because it’s more reactive
we so this because iron oxide is originally in the ore

60
Q

what is titanium used for?

A

medical implants

strong but not corrosive

61
Q

what is the equation for complete combustion?

A

hydrocarbon + oxygen = carbon dioxide + water ALWAYS MAKES THAT

62
Q

what is the equation for incomplete combustion?

A

hydrocarbon + 1.5oxygen = carbon monoxide + water

63
Q

are alkenes saturated?

A

NO

64
Q

which are the most useful hydrocarbons?

A

short chain molecules - why cracking is done

65
Q

monomers are always?

A

alkenes