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GCSE CHEMISTRY C4-6 > C6.1 > Flashcards

C6.1 Flashcards

1
Q

what are the three essential elements needed by plants?

A

nitrogen, phosphorus and potassium

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2
Q

what happens is plants have limited supply of their essential elements in the soil?

A

they will show signs of mineral deficiency and the quality and yield of food will be reduced

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3
Q

what are the symptoms of plants if they are nitrogen deficient?

A

poor growth and yellow leaves

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4
Q

what are the symptoms of plants if they are phosphorous deficient?

A

poor root growth and discoloured leaves

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5
Q

what are the symptoms of plants if they are potassium deficient?

A

poor fruit growth and discoloured leaves

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6
Q

what are fertilisers?

A

substances added to soil that replace elements and nutrients used by plants as they grow

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7
Q

in what conditions can plant roots only absorb elements ?

A

if they are in a water soluble form

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8
Q 
what does:
nitrogen
ammonium
phosphorus
potassium 
have to be in order for plants to be able to absorb them?
A

nitrate ions - NO3 -
ammonium ions - NH4 +
phosphate ions - PO4 3-
potassium ions - K +

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9
Q

what is the name for fertilisers that provide nitrogen, phosphorus and potassium in water soluble compounds known as?

A

NPK fertilisers

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10
Q

what is the Haber process?

A

an industrial process to make ammonia from nitrogen an hydrogen

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11
Q

what is the chemical equation for the Haber process?

A

N2(g) + 3H2(g) <=> 2NH3 (g)

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12
Q

how many tonnes of ammonia are manufactured in the world per year?

A

150 million

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13
Q

what are the raw materials required for the Haber process?

A

air, natural gas and steam

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14
Q

how is nitrogen manufactured?

A

by fractional distillation of liquefied air (air is 98% nitrogen)

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15
Q

how is hydrogen manufactured?

A

by reacting natural gas (mostly methane) with steam

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16
Q

what happens in a fertiliser factory?

A

several different processes are integrated so a range of compounds for fertilisers can be made

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17
Q

name 4 compounds for fertilisers that can be created in a fertiliser factory

A

1) ammonium nitrate - NH4NO3
2) ammonium sulfate - (NH4)3SO4
3) ammonium phosphate - (NH4)3PO4
4) potassium nitrate- KNO3

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18
Q

what are the 4 steps to making potassium sulfate in a lab?

A

1) put dilute potassium hydroxide into a conical flask and add a few drops of phenolphthalein indicator to enable you to determine when the alkali has been neutralised
2) add dilute sulfuric acid from a burette or dropping pipette stopping when the indicator changes from pink to colourless
3) add activated charcoal which attracts the phenolphthalien and then filter the mixture to remove the charcoal and phenolphthalein attached to it
4) heat filtrate to make water evaporate leaving potassium sulfate behind but it shouldn’t be heated to dryness

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19
Q

what can potassium sulfate be made from?

A

potassium hydroxide and sulfuric acid

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20
Q

what are the 3 steps of making ammonium sulfate in a lab?

A

1) place dilute ammonia solution in a conical flak with methyl orange indicator
2) add dilute sulfuric acid from a burette or dropping pipette stopping when the indicator changes from yellow to red
3) when you reach the end point add a little extra ammonia solution to ensure the reaction is complete and any remaining ammonia will be lost in evaporation

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21
Q

what are the hazards with making ammonium sulfate in the lab?

A

1) ammonia solution releases small amounts of ammonia in gas state which has an irritating sharp smell so you have to try not breath it in
2) excess ammonia is given off in the gas state when the solution is warmed

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22
Q

what is the batch process? when is it used?

A

a chemical process that makes products in limited amounts at different times and is used in the lab

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23
Q

what is the continuous process? when is it used?

A

chemical process that makes products in large amounts at a time and is used in industrial processes and are rarely shut down

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24
Q

what is the difference between the materials used in a laboratory and the materials used in fertiliser factories?

A

laboratories use pure substances bought from a chemical manufacturer but fertiliser factories use raw materials that are either purified before or after the reaction

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25
Q

what is the difference between the rate of production in the batch process vs the continuous process?

A

batch has low rate continuous has high

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26
Q

what is the difference between the relative cost of equipment in the batch process vs the continuous process?

A

batch is low continuous is high

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27
Q

what is the difference between the number of workers needed in the batch process vs the continuous process?

A

batch has a large number but continuous has low

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28
Q

what is the difference between the shut down periods in the batch process vs the continuous process?

A

batch have frequent shut down periods while continuous are rare

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29
Q

what is the difference between the ease of automating the process in the batch process vs the continuous process?

A

batch is low and continuous is high

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30
Q

what are the conditions used for the Haber process? (temperature and pressure)

A

pressure of 200 atmospheres (20 MPa)

temerature of 450C

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31
Q

what type of catalyst is used in the Haber process?

A

iron catalyst

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32
Q

what yield do the conditions usually chosen for the Haber process create?

A

a 30% equilibrium yield of ammonia

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33
Q

what would happen if the pressure increased in the chosen conditions fro the Haber process?

A

the equilibrium yield of ammonia would increase but it would be hazardous and expensive and the higher yield wouldn’t justify the additional costs of the high pressure

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34
Q

what type of reaction is the forward reaction of the Haber process?

A

exothermic

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35
Q

what type of reaction is the backward reaction of the Haber process?

A

endothermic

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36
Q

what would happen if you increased the temperature of the chosen conditions of the Haber process?

A

the equilibrium yield would decrease

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37
Q

why is 450C chosen as the temperature for the Haber process?

A

because it is a compromise. low enough to achieve a reasonable equilibrium yield but high enough to achieve reasonable rate of reaction

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38
Q

what temperature does the catalyst in the Haber process work at best?

A

400C

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39
Q

why are the mixture of gases in the Haber process cooled?

A

so that the ammonia is liquefied allowing it to be removed and the un-reacted nitrogen and hydrogen to be recycled improving the overall yield to 97%

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40
Q

what are the 3 raw materials required to make sulfuric acid?

A

sulfur, air and water

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41
Q

what happens in the first stage of creating sulfuric acid?

A

sulfur burns in air to produce sulfur dioxide

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42
Q

what is the equation for the first stage of creating sulfuric acid?

A

sulfur + oxygen -> sulfur dioxide

S (s) + O2(g) -> SO2(g)

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43
Q

what is the name of the second stage of creating sulfuric acid?

A

the contact process

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44
Q

what is the contact process

A

the industrial process that makes products in large amounts over time

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45
Q

what happens in the contact process?

A

sulfur dioxide and oxygen react together to produce sulfur trioxide

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46
Q

what is the equation for the contact process?

A

2SO2(g) + O2(g) <=> 2SO3(g)

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47
Q

what are the conditions usually chosen for the contact process when making sulfur trioxide? (pressure/temp/catalyst)

A

pressure of 2 atmospheres (200 kPa)
temperature of 450C
vanadium oxide catalyst

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48
Q

what is the yield in the chosen conditions for creating sulfur trioxide when making sulfuric acid?

A

98%

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49
Q

what happens in the third stage of making sulfuric acid?

A

sulfur trioxide is converted into sulfuric acid

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50
Q

what is the equation for he third stage f making sulfuric acid?

A

water + sulfur trioxide -> sulfuric acid

H2O(l) + SO3(g) -> H2SO4 (aq)

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51
Q

what would happen if you increased the chosen pressure for the reaction creating sulfur trioxide?

A

it would be unnecessary because 2 atmospheres is enough to push the gases through the converter and 3 is not necessary

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52
Q

what would happen if you increased the temperature of the reaction to create sulfur trioxide?

A

the equilibrium yield of sodium trioxide would decrease as a high equilibrium yield is favoured by a low temperature

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53
Q

why is the temperature of 450C chosen when creating sodium trioxide?

A

it is a compromise that is low enough to achieve a reasonable equilibrium yield but a high enough rate of reaction and the catalyst only works above 380 C

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54
Q

why is stage three of creating sulfuric acid carried out in two pahses?

A

because it is an extremely exothermic reaction that would produce a hazardous acidic mist

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55
Q

what is the first stage of the third phase of creating sulfuric acid?

A

sulfur trioxide is passed through concentrated sulfuric acid to make a compound called oleum

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56
Q

what is the equation for the first stage of the third phase of creating sulfuric acid?

A

H2SO4(l) + SO3 (g) => HS2O7 (l)

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57
Q

what is the second stage of the third phase of creating sulfuric acid?

A

the oleum created in the first phase is then added to water and the reaction makes a larger volume of concentrated sulfuric acid

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58
Q

what is the equation for the second stage of the third phase of creating sulfuric acid ?

A

H2S2O7 (l) + H2O (l) => 2H2SO4 (aq)

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59
Q

what are renewable raw materials?

A

materials that can be replaced as they are used and in theory should not run out

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60
Q

what is ethanol made from?

A

plant sugars using fermentation

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61
Q

how is ethanol made? (renewable)

A

yeast cells are single celled fungi and catalyse the conversion of glucose solution into carbon dioxide and ethanol

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62
Q

what is the equation for making ethanol? (renewable)

A

glucose -> carbon dioxide + ethanol

C6H12O6 (aq) -> 2CO2 (g) + 2C2H5OH (aq)

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63
Q

what happens if the temperature is too low or too high when using yeast?

A

the yeast cells become inactive if it is too low and denature if it is above 50C

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64
Q

what conditions is fermentation carried under?

A

35C and normal atmospheric pressure (100 kPA)

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65
Q

what are non renewable raw materials?

A

material that can be used faster than they can be replaced and will run out one day if you continue using them

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66
Q

how is ethanol made? (non renewable)

A

it is obtained from crude oil which is non renewable and can be produced through the hydration of ethene

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67
Q

what is hydration?

A

a reaction where water is added

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68
Q

what is the equation fro making ethanol? (non renewable)

A

ethene + steam -> ethanol

C2H4 (g) + H2O (g) <=> C2H50H (g)

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69
Q

where can renewable ethanol be produced?

A

in the lab and with industrial fermentation with more complex equipment but the same conditions

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70
Q

where can non renewable ethanol be produced?

A

only as an industrial process

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71
Q

what are the conditions required for creating non renewable ethanol? temperature/pressure/catalyst

A

temperature of 300C
pressure of 60 atmospheres
catalyst of phosphoric acid

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72
Q

what is the difference between the cost of raw material for fermentation of sugars vs hydration of ethene?

A

fermentation is a low cost but hydration is a high cost

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73
Q

what is the difference between the conditions for fermentation of sugars vs hydration of ethene?

A

fermentation : moderate temperature and normal pressure

hyrdation: high temperature and pressure

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74
Q

what is the difference between the energy requirements for fermentation of sugars vs hydration of ethene?

A

fermentation requires low energy but hydration requires high

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75
Q

what is the difference between the rate of reaction for fermentation of sugars vs hydration of ethene?

A

fermentation has a low rate but hydration has a high rate

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76
Q

what is the difference between the percentage yield for fermentation of sugars vs hydration of ethene?

A

fermentation : low - 15%

hydration: high - 95%

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77
Q

what is the difference between the purity of the product produced for for fermentation of sugars vs hydration of ethene?

A

fermentation: low - needs filtering and fractional distillation
hydration: high - there are no by-products

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78
Q

what will the choice for production of ethene depend upon?

A
  • availability of materials
  • cot of materials
  • cost of energy required
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79
Q

what is an ore?

A

a rock or mineral that contains enough metal/metal compound to make it economical to extract the metal

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80
Q

what metal compound is found in the ore malachite?

A

copper carbonate

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81
Q

what metal is found in the ore bauxite?

A

aluminium oxide

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82
Q

what metal is found in the ore haematite?

A

iron (III) oxide

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83
Q

what must happen to an ore in order to separate a metal from an ore?

A

the ore must be mined and processed to separate the metal from the other substances in the ore. the metal is extracted from the pure metal compound using a chemical reaction

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84
Q

what does the method of extracting a metal from its ore depend upon?

A

the position of the metal in the reactivity series

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85
Q

what type of met to extract metal from an ore if the metal is less reactive than carbon?

A

cheaper methods are used

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86
Q

why isnt electrolysis used to extract all metals?

A

because it is an expensive process

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87
Q

how are copper and iron extracted from their ores?

A

they are extracted by heating their compounds with carbon or carbon monoxide because they are less reactive than carbon

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88
Q

how many stages are required to extract copper from copper sulfide?

A

two

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89
Q

what happens in the first stage of extracting copper from copper sulfide?

A

coper(ll) sulfide is “roasted” in air

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90
Q

what is the equation for roasting copper sulfide in the first phase of extracting copper from copper sulfide?

A

copper(ll) slufide + oxygen -> copper(ll) oxide + sulfur dioxide
2CuS (s) + 3O2 -> 2CuO (s) + 2SO2

91
Q

what happens in the second stage of extracting copper from copper sulfide?

A

copper (II) oxide it heated with carbon

92
Q

what is the equation for heating copper oxide with carbon in the second stage of extracting copper from copper sulfide?

A

copper (II) sulfide + oxygen -> copper + carbon dioxide

2CuS(s) + 3O2(g) -> 2Cu(s) +CO2(g)

93
Q

what types of reaction is the one for extracting copper from copper sulfide?

A

it is a redox reaction

94
Q

why is the reactions of extracting copper from copper sulfide a redox reaction?

A

because copper looses oxygen and is reduced and carbon gains oxygen and is oxidised and in the reaction carbon is acting as a reducing agent

95
Q

what three gases can you heat copper (II) oxide with to get copper?

A

methane, hydrogen and carbon(after burning in air)

96
Q

what is used to extract iron from its ore?

A

a large industrial reaction container called a blast furnace

97
Q

how much iron do modern blast furnaces produce each day?

A

10000 tonnes per day

98
Q

what 3 raw materials are added to the top of blast furnaces and why are they added?

A

1) iron ore such as haematite which contains iron(III) oxide
2) coke
3) limestone to purify the iron

99
Q

how is coke made?

A

it is made up of mostly carbon made by heating coal in absent air

100
Q

what is the main reducing agent in a blast furnace?

A

carbon monoxide although carbon can reduce iron(III) oxide into iron

101
Q

how many stages are there to producing iron in a blast furnace?

A

three

102
Q

when is carbon monoxide produced in a blast furnace?

A

when coke reacts with carbon dioxide

103
Q

what happens in the first stage of producing iron in a blast furnace?

A

coke burns in hot air making carbon monxide

104
Q

what is the equation for the first stage of producing iron in a blast furnace?

A

C(s) + O2(g) ->CO2 (g)

105
Q

what happens in the second stage of producing iron in a blast furnace?

A

more coke reduces the carbon dioxide making carbon monoxide

106
Q

what is the equation for the second stage of producing iron in a blast furnace?

A

C(s) + CO2(g) -> 2CO(g)

107
Q

what happens in the third stage of producing iron in a blast furnace?

A

carbon monoxide reduces iron(III) oxide to form iron at around 1500C

108
Q

what is the equation for the third stage of producing iron in a blast furnace?

A

3CO(g) + Fe2O3(s) -> 3CO2(g) + 2Fe(l)

109
Q

what happens after the three stages of producing iron in a blast furnace?

A

the molten iron trickles downwards in the blast furnace

110
Q

why does the molten iron have to be purified by limestone after it has been produced by the blast furnace?

A

because it contains sandy impurities from the iron ore

111
Q

how many stages are there to purifying molten iron from a blast furnace with limestone?

A

two

112
Q

why is limestone used to purify molten iron from a blast furnace?

A

because it mostly contains calcium carbonate

113
Q

what happens in the first stage of purifying molten iron from a blast furnace with limestone?

A

calcium carbonate decomposes in the high temperature

114
Q

what is the equation for the first stage of purifying molten iron from a blast furnace with limestone?

A

CaCO3(s) -> CaO(s) + CO2(g)

115
Q

what happens in the second stage of purifying molten iron from a blast furnace with limestone?

A

the calcium oxide formed in the first stage reacts with silica from the sandy impurities to form calcium silicate

116
Q

what is the equation for the second stage of purifying molten iron from a blast furnace with limestone?

A

CaO (s) + SiO2(g) -> CaSiO3 (l)

117
Q

what is the name for molten calcium silicate formed from purifying molten iron from a blast surface with limestone?

A

slag

118
Q

what happens once the molten iron from the blast furnace has been purified?

A

the slag floats on top and both are removed separate from the bottom of the blast furnace

119
Q

how does aluminium exist naturally? what ore is it found in?

A

exists naturally as aluminium oxide Al2O3 found in the ore bauxite

120
Q

how reactive is aluminium in comparison to carbon? what does this mean about the process which must be used to extract it?

A

its more reactive so has to be extracted using electolysis

121
Q

what problem is there with using electrolysis for separating aluminium from its ore?

A

electrolysis only works if the compound is in solution or molten but aluminium doesn’t dissolve in water and has a very high melting point

122
Q

what is the melting point of aluminium? why is it hard to heat it to this temperature?

A

over 2000 C and it would be extremely expensive to heat it to this temperature

123
Q

what happens in order for aluminium to be separated from its ore?

A

it is dissolved in molten cryolite which has a lower meting point than aluminium

124
Q

what temperature can electrolysis of aluminium happen at if cryolite is used?

A

950 C

125
Q

what is the aluminium oxide and cryolite contained in when electrolysis takes place?

A

a huge electrolysis cell made from steel lines with graphite

126
Q

what part of the apparatus used in electrolysis of aluminium oxide acts as the cathode?

A

the graphite lining of the cell acts as the negative electrode

127
Q

what part of the apparatus used in electrolysis of aluminium oxide acts as the anode?

A

the series of large graphite blocks placed in the electrolyte act as the positive electrodes

128
Q

what is produced at the cathode in electrolysis of aluminium oxide?

A

aluminium

129
Q

what is produced at the anode in electrolysis of aluminium oxide?

A

oxygen

130
Q

what is produced when oxygen reacts with the large graphite anodes?

A

carbon dioxide

131
Q

what usually happens to mines when they are abandoned?

A

they flood

132
Q

what happens when mines flood?

A

metal sulfides oxidise under water producing sufuric acid which reacts with other metal ores forming soluble metal compounds which leave with the water as it drains from the mine

133
Q

what can cause the reaction of metal ores to react faster?

A

bacteria

134
Q

what happens in bio-leaching?

A

bacteria oxidise iron(II) and sulfide ions and use the energy transferred and form sulfuric acid in the presence of water and oxygen

135
Q

what happens to the sulfuric acid produced by bio-leaching?

A

it breaks down copper sulfide ores and other minerals releasing copper(II) ions and other metal ions

136
Q

what is bio-leaching?

A

biological method of extracting metals in which bacteria speed up reactions that release soluble metal compounds from metal sulfides

137
Q

name 3 benefits of bio-leaching

A

1) it is cheaper than traditional methods of mining and processing
2) you can extract metals from low grade ores that would be unprofitable to extract normally
3) the bacteria occur naturally and don’t need any special treatment
4) it doesn’t release harmful sulfur dioxide into the atmosphere

138
Q

name 2 disadvantages of bio-leaching

A

1) it is slow

2) toxic substances such as sulfuric acid can be produced which could escape into water supplies/ the soil

139
Q

what is phytoextraction?

A

a biological method of metal extraction in which plants absorb metals through their roots and concentrate them into their cells

140
Q

what are the steps to phytextraction?

A

1) crops are planted in soil containing a low grade ore or mine
2) a complexing agent is added if necessary so the plants can absorb the metal ions easier
3) the plants are harvested and then burned to produce an ash with a high concentration in the metal
4) the bio-ore is smelted(extracted) to yeild metal

141
Q

what are the advantages of phytoextraction? name 3

A

1) cheaper than traditional mining and processing
2) produces less waste
3) involves smaller energy transfers
4) close to being a carbon neutral activity
5) can contribute to sustainable development

142
Q

what are the disadvantages of phytoextraction?

A

1) slow

2) crops may need replanting and harvesting for several years before available metal is removed from the soil

143
Q

how is phytoextraction close to being carbon neutral?

A

burning plants release carbon dioxide but they also absorb carbon dioxide for photosynthesis as they grow

144
Q

what is carbon neutral?

A

a process where there is no overall release of carbon dioxide into the atmosphere

145
Q

what is an alloy?

A

a mixture f two or more elements and at least one of which is a metal

146
Q

what is steel?

A

an alloy where iron is mixed with other metals and carbon

147
Q

name 2 properties of steel

A

high tensile strength and ductile

148
Q

what is tensile strength?

A

the measure of how strong a metal is when stretched

149
Q

name 5 alloys

A

1) steel
2) duralumin
3) solder
4) brass
5) bronze

150
Q

what is the main metal in steel?

A

iron

151
Q

what are the typical uses of steel?

A

buildings, bridges and cars

152
Q

what are the main 2 metals in duralumin

A

aluminium and copper

153
Q

what is druralumin normally used for?

A

aircraft parts

154
Q

what are the main 2 metals in solder?

A

tin and copper

155
Q

what are the typical uses of solder?

A

joining electrical components and copper pipes

156
Q

what are the 2 main metals in brass?

A

copper and zinc

157
Q

what are the typical uses of brass?

A

musical instruments and coins

158
Q

what are the 2 main metals in bronze?

A

copper and tin

159
Q

what are the typical uses of bronze?

A

bells and propellers for ships

160
Q

what is the melting point of tin?

A

232C

161
Q

what is the melting point of copper?

A

1085C

162
Q

what is the meting point of solder?

A

227C

163
Q

how is the melting point of solder useful when joining electrical components?

A

it joins it without damaging it as the hot solder in the liquid state flows into the gaps between the electrical components and solidifies quickly and allows an electrical current to pass through

164
Q

what happens to metal particles when they are bent or stretched?

A

layers of metal atoms slide oer eachother

165
Q

why are alloys stronger and harder than the individual metals themselves?

A

the atoms are different sizes making it more difficult for the atoms to slide over each other

166
Q

name 3 properties of brass. what do these properties make brass useful for?

A

1)hard/strong
2)good conductor of electricity
3)resists corrosion
makes it useful for making pins for electrical plugs

167
Q

name 3 properties of bronze which makes it better than copper

A

1) resists corrosion

2) stronger/ harder thin copper

168
Q

why is bronze useful for metal artwork?

A

it expands slightly as it solidifies so fills in tiny details in an artists mould

169
Q

what is corrosion?

A

the reaction of a metal with substances in its surroundings such as air and water

170
Q

what is special about the corrosion of silver?

A

silver doesn’t corrode easily with oxygen in the air or water but will corrode in the presence of hydrogen sulfide (H2S)

171
Q

what naturally produces hydrogen sulfide?

A

bacteria

172
Q

what happens when silver reacts with hydrogen sulfide?

A

hydrogen sulfide reacts with silver when water and oxygen are also present producing a thing layer of black silver sulfide (Ag2S)

173
Q

what metals don’t corrode? why?

A

gold and platinum because they are unreactive

174
Q

what do you call it when iron and steel corrode?

A

rusting

175
Q

what type of reaction is rusting?

A

redox

176
Q

what happens to iron when it rusts?

A

it is oxidised to hydrated iron(III) oxide when it reacts with oxygen and water

177
Q

what is the equation for rusting?

A

iron + oxygen + water -> hydrated iron (III) oxygen

178
Q

what does hydrates iron (III) oxide look like?

A

orange brown rust that flakes off the surface of an object leaving fresh metal underneath and can continues until an object has completely corroded away

179
Q

name four mathods of preventing/ reducing rusting

A

1) paining
2) coating with oil/grease/plastic
3) galvanising (plating with zinc)
4) plating with tin

180
Q

what are the issues with using paint/oil/grease to protect metals from rusting?

A

if the paint is damaged rusting starts on the exposed metal and continues underneath until it flakes of exposing fresh metal to air/water

181
Q

what is sacrificial protection?

A

rust prevention where a more reactive metal than iron such as magnesium or zinc corrodes in preference to iron/steel so the more reactive metal corrodes first

182
Q

when is sacraficial protection used?

A

when painting is difficult eg on ship hulls where they have zinc/magnesium blocks bolted onto their hulls below the waterline

183
Q

what is a problem with using sacrificial corrosion on boats hulls?

A

they gradually ccorrode away and have to be replaced

184
Q

what is the half equation for iron (III) in rusting?

A

Fe -> Fe 3+ + 3e-

185
Q

what is the rule for reactivity of ametal in terms of electrons?

A

the more reactive a metal is the easier it looses its electrons

186
Q

what is metal plating?

A

where a layer of metal is plated onto a iron or steel metal object preventing air and water form reaching the iron/steel below

187
Q

what si galvanising?

A

coating iron/steel with a thin layer of zinc

188
Q

what two things does the thin layer of zinc from galvanising do after it has cooled?

A

1) it stops air and water reaching the iron/steel below

2) it acts as a sacrificial metal so that the object is protected even if the zinc layer is damaged

189
Q

what are the two ways in wich you can plate a metal with tin?

A

1) electroplating the steel object with tin

2) dipping the object in molten tin

190
Q

what is an issue with tin plating?

A

tin is less reactive than iron and if the tin layer is damaged the steel acts as a sacrificial metal for the tin so rusts faster than normal

191
Q

what are ceramics?

A

hard non metallic materials

192
Q

give 4 examples of ceramic materials

A

1)brick
2)china
3)porcelain
4)

193
Q

what are ceramics made from? what is their structure like?

A

contain metals and non - metals combined to form giant ionic lattices or giant covalent structures

194
Q

what are the typical properties of ceramc?

A

1) high melting points
2) hard stiff and brittle
3) poor conductors of electricity and heat

195
Q

why are most ceramics unreactive?

A

their compounds are mostly oxides

196
Q

how is glass produced?

A

by melting sand and them allowing it to cool and solidify

197
Q

what are the properties of glass?

A

1) irregular giant structure
2) no crystals
3) transparent

198
Q

how are most ceramics made?

A

by heating clay to high temperatures causing tiny crystals form joined together by glass

199
Q

what is china/ porcelain usually coated in and why?

A

usually coated in a glaze and reheated forming a smooth hard waterproof surface

200
Q

what are the 4 desired qualities you want when choosing the material for a metal cable

A

1) good conductor of electricity
2) lightweight
3) strong so it doesn’t stretch or snap easily
4) resist corrosion

201
Q

what three metals could be considered for use in eletrical cables?

A

aluminium, copper and steel

202
Q

why is aluminium chosen for overhead electricity? (in comparison to steel)

A

it is a good conductor and less dense than steel but not as strong

203
Q

why is copper chosen for electrical wires in comparison to steel and aluminium?

A

it is the best conductor of electricity but has a low tensile strength and the highest density meaning it will be heavy

204
Q

what must insulators do?

A

prevent energy from escaping

205
Q

what is poly(propene)? what are its properties? (in comparison to glass and porcelain)

A

it is a tough flexible polymer with the poorest electrical resistance and its tensile strength is the lowest so would snap easily when stretched and has the lowest comprehensive strength so would squash easily

206
Q

what is compressive strength?

A

the measure of how strong a material is when squashed

207
Q

what are the properties of porcelain (in comparison to glass and poly(propene)?

A

lower resistance than glass but higher compressive strength

208
Q

what would be the most suitable insulator for where cables are fixed to the top of a structure

A

porcelain

209
Q

what is a composite material?

A

a material made from two or more materials combined together and each has different properties making te properties of the composite material different to that of the materials it contains

210
Q

name 3 ways in which a composite material may be different to the materials it contains

A

1) stronger
2) less dense
3) cheaper than separate components alone

211
Q

name 3 properties of cotton fabric

A

1) lightweight
2) comfortable
3) not hard wearing

212
Q

what is polyester cotton?

A

a composite material made by weaving cotton thread ith polyester fibre and artificial polymer

213
Q

what are the properties of polyester-cotton?

A

comfortables, hardwearing and easy to wash/dry

214
Q

what is resin?

A

a substance that changes from the liquid state to the solid state because of chemical reactions

215
Q

what fibres do many polymer materials consist of?

A

fibres embedded in polymer resin

216
Q

what is the difference between polymer fibres and polymer resin?

A

polymer fibres have a low density but high tensile strength but are brittle while resin is hardwearing but not strong

217
Q

what are the properties of the composite material created by combining polymer fibres and resin togtether?

A

lightweigh, strong and hard material

218
Q

what does fibreglass contain?

A

glass fibres in a resin

219
Q

what is fibreglass used for?

A

canoes, boats and surfboards

220
Q

what is carbon fibre made of?

A

carbon fibres in a resin

221
Q

what is carbon fibre used for?

A

racing cars and aircraft parts as it is more expensive than fibreglass

222
Q

what is concrete?

A

a composite material made up of aggregate(small stones), sand and cement

223
Q

what happens when water is added to concrete?

A

chemical reactions happen binding he ingredients of the concrete together

224
Q

what is the compressive strength of concrete? what does this make it useful for?

A

high compressive strength making it useful for building foundations

GCSE CHEMISTRY C4-6 (1 decks)

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