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edexcel igcse chemistry > unit two: inorganic chemistry > Flashcards

unit two: inorganic chemistry Flashcards

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1
Q

what are the group one metals called

A

alkali metals

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2
Q

what are lithium, sodium and potassium stored in and why?

A

oil to prevent them from reacting with oxygen and water.

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3
Q

properties of alkali metals

A

good conductors of electricity and heat
soft and can easily be cut with a knife
low melting and boiling points compared with more typical metals such as iron and copper
low densities

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4
Q

properties of lithum, sodium and potassium

A

shiny surface when freshly cut with a knife, but the surface quickly becomes dull as the metal reacts with oxygen in the air.

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5
Q

what does lithium, sodium and potassium form when they burn in air

A

white solid oxides

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6
Q

what is the equation for when lithium, sodium and potassium burns in air

A

4M +O2 –> 2M2O

where M = lithium, sodium or potassium

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7
Q

what colour flame does lithium burn with

A

red

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8
Q

what colour flame does sodium burn with

A

yellow

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9
Q

what colour flame does potassium burn with

A

lilac

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10
Q

do lithium sodium and potassium react with water

A

yes vigorously

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11
Q

what do lithium sodium and potassium give when they react with water

A

an alkaline solution of the metal hydroxide as well as hydrogen gas

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12
Q

observations when lithium reacts with warer

A

moves around the surface of the water
hissing sound
bubbles of gas
gets smaller and smaller, eventually disappears

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13
Q

observations when sodium reacts with water

A 
moves around the surface of the water
hissing sound
bubbles of gas 
melts into a shiny ball
gets smaller and smaller, eventually disappears
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14
Q

observations when potassium reacts with water

A 
moves around the surface of the water
hissing sound
bubbles of gas
melts into a shiny ball
burns with a lilac-coloured flame
gets smaller and smaller, eventually disappears
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15
Q

order of reactivity of lithium, sodium and potassium

A

potassium - sodium - lithium (more reactive with increasing atomic number)

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16
Q

what happens involving reactivity as you move down group 1

A

reactivity of the elements increases

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17
Q

why is potassium more reactive than sodium and lithium

A

it requires less energy to overcome the electrostatic forces of attraction between the negatively charged electron and the positively charged nucleus.

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18
Q

physical state and colour of chlorine at room temperature

A

pale green gas

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19
Q

physical state and colour of bromine at room temperature

A

red-brown liquid

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20
Q

physical state and colour of iodine at room temperature

A

black solid

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21
Q

what happens when chlorine reacts with iron

A

brown smoke is formed and a brown solid is left behind

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22
Q

what happens when bromine reacts with water

A

bromine smoke and a brown solid are formed

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23
Q

what happens when iodine reacts with water

A

brown smoke and a brown solid are formed

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24
Q

what is a halide

A

a compound of a halogen and one other element

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25
Q

whats in a metal halide

A

a compounf of a halogen and a metal

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26
Q

what happens when chlorine reacts with hydrogen

A

explosion when exposed to UV radiation

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27
Q

what happens when bromine reacts with hydrogen

A

the vapour formed will react when heated

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28
Q

what happens when iodine reacts with hydrogen

A

the vapour will react when heated, but the reaction does not go to completion

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29
Q

when is a metal halide formed

A

e.g. when a halogen is reacted with iron

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30
Q

when is a hydrogen halide formed

A

e.g. when a halogen is reacted with hydrogen

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31
Q

general rule for displacement reactions

A

a halogen will displace a less reactive halogen for an aqeous solution of its halide.

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32
Q

what colour is aqueous chlorine

A

very pale green, usually diluted to colourless

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33
Q

what colour is aqueous bromine

A

orange but will turn yellow when diluted.

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34
Q

what colour is aqueous iodine

A

brown

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35
Q

in displacement reactions, the halogen molecule is often being reduced because

A

it is gaining electrons

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36
Q

in displacement reactions, the halide ions are being oxidised because

A

they are losing electrons

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37
Q

when both reduction (of a halogen) and oxidisation (of a halide) is happening the reaction is called a

A

redox reaction

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38
Q

why does reactivity decrease down the group of halogens

A

the increasing size of the atom means it will be harder for the atom to quickly gain an electron

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39
Q

what percentage of air is nitrogen

A

78%

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40
Q

what percentage of air is oxygen

A

21%

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41
Q

what percentage of air is argon

A

0.9%

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42
Q

what percentage of air is carbon dioxide

A

0.04%

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43
Q

how would you measure the oxygen content of air using copper

A

repeatedly pass 100cm cubed of air back and forwards over a silicia tube packed with copper, by heating it with a blue bunsen flame. the copper will react with the oxygen to form black copper oxide.

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44
Q

what would the results be after measuring the oxygen content of air using copper

A

the final volume of air in the syringe will be approximately 79cm cubed, showing that 21cm cubed has reacted. therefore 21% of the air was oxygen.

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45
Q

how would you measure the oxygen content of air using iron

A

place wet iron fillings at the end of a burette and place in a water trough. the iron will react with oxygen, and over several days the volume of air in the buretter will have decreased.

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46
Q

how would you measure the oxygen content of air using phosphorus

A

put a piece of white phosphorus inside a tube inside a beaker filled with water. the water levels inside the tube and the beaker should be equal. touch the phosphorus with a hot metal rod and burn it. when it stops burning the water level inside the tube will have increased due to the oxygen being used up.

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47
Q

observations of magnesium when it burns in oxygen

A

bright white flame to form a white powder

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48
Q

observations of carbon when it burns in oxygen

A

yellow-orange flame to form a colourless gas.

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49
Q

observations of sulfur when it burns in oxygen

A

blue flame to form a colourless gas

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50
Q

describe magnesium oxide

A

basic oxide, slightly soluble in water and a pH of about 10. reacts with water to form magnesium hydroxide

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51
Q

describe carbon and sulfur dioxide

A

acidic oxides, dissolve in water to form acidic solutions.

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52
Q

the reaction between any metal carbonate and an acid will produce

A

carbon dioxide

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53
Q

when metal carbonates are heated what is produced

A

carbon dioxide

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54
Q

observations of the thermal decompisition of copper carbonate

A

green copper carbonate and black copper oxide are heated, and if carbon dioxide is produced the limewater attacahed to it will turn milky

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55
Q

observations of the thermal decompisition of magnesium carbonate

A

no change, stays white

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56
Q

observations of the thermal decomposition of calcium carbonate

A

no change stays white

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57
Q

observations of the thermal decomposition of zinc carbonate

A

white to yellow when hot and white again when cold

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58
Q

observations of the thermal decomposition of sodium carbonate

A

no observable change, stays white

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59
Q

how does production of carbon dioxide enhance the greenhouse effect

A

more heat is re-emitted by the atmosphere and less heat escapes into space .

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60
Q

effects of global warming

A

polar ice caps melt, sea levels rise, more extreme weather

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61
Q

list the reactivity series

A 
potassium
sodium
lithium
calcium
magneisum
aluminium
zinc
iron
tin
lead
copper
silver
gold 
platinum
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62
Q

reducing metal oxides

A

a metal oxide is a compound of metal and oxygen. when the oxygen is removed, the oxide is reduced. it can be reduced by heating it with a metal higher up in the reactivity series.

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63
Q

(reactivity series) the substance that carries out the reduction is called the

A

reducing agent

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64
Q

why is hydrogen in the reactivity series

A

although not a metal, it can be displaced from an aquous solution like a metal, only this time, the solution is an acid.

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65
Q

where is carbon in the reactivity series

A

it can combine with oxygen to form carbon dioxide, between aluminium and zinc.

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66
Q

what is rusting

A

an oxidation reduction

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67
Q

the iron reacts with water and oxugen to form rust or?

A

hydrated iron (III) oxide

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68
Q

what is coating

A

stopping oxygen or water reaching the surface of the metal

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69
Q

examples of coating

A

oiling (bicycle chains)
greasing (nuts and bolts)
painting (car body panels)

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70
Q

what is alloying

A

stainless steel is an iron alloy that does not rust. used for sinks etc

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71
Q

what is sacrificial protection

A

attaching a more reactive metal such as magnesium slows down rusting.

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72
Q

what is plating

A

iron objects can be covered with a thin layer of metal.

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73
Q

examples of plating

A

food cans plated with tin

buckets plated with zinc (also gives sacrifical protection.)

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74
Q

give the only two elements that occur as elements in their ores

A

silver and gold (most unreactive)

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75
Q

how can sulfides be easily converted into oxides

A

by roasting (heating in air)

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76
Q

how to extract metal from the first 6 metals in the reactivity series

A

electrolysis of the molten chloride or molten oxide

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77
Q

how to extract metal from the middle 3 metals in the reactivity series (zinc, iron, copper)

A

heat with a reducing agent such as carbon or carbon monoxide

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78
Q

how to extract metal from the last 2 metals in the reactivity series (silver, gold)

A

you don’t, they occur naturally as elements

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79
Q

uses of aluminium

A

aeroplane bodies
saucepans
food cans
window frames

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80
Q

uses of iron

A

car bodies
iron nails
ships and bridges

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81
Q

why is aluminium and iron rarely used by themselves

A

they aren’t very strong so aluminium alloys are usually used instead.

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82
Q

how can aluminium be stengthened

A

by adding other elements such as silicon, copper or magnesium.

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83
Q

what is pure iron also called

A

wrought iron

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84
Q

describe the structure of ions in a pure metal

A

the ions in a pure metal are the same size and fit neatly in layers able to slide over each other. a relatively small force is required to slide these layers over each other.

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85
Q

describe the structure of ions in an alloy

A

the ions are different sizes so there are no regular layers, meaning it requires a greater force to slide these layers of ions over each other.

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86
Q

which end of the pH scale is acidic

A

0-6 (decreasingly so)

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87
Q

which end of the pH scale is alkaline

A

8-14 (increasingly so)

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88
Q

which number on the pH scale is neutral

A

7

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89
Q

give an example of a neutral substance

A

pure water

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90
Q

what colour does litmus paper turn in a solution where the pH is 5 or less

A

red

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91
Q

what colour does litmus paper turn in a solution where the pH is 8 or more

A

blue

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92
Q

what colour does litmus paper turn in a solution between 5 and 8

A

a shade of purple (between red and blue)

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93
Q

what colour is methyl orange in a solution where the pH is 3 or less

A

red

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94
Q

what colour is methyl orange in a solution where the pH is 5 or more

A

yellow

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95
Q

what colour is methyl orange in a solution where the pH is between 3 and 5

A

orange (between red and yellow)

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96
Q

what colour is phenolphthalein in a solution where the pH is 8 or less

A

colourless

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97
Q

what colour is phenolphthalein in a solution where the pH is 10 or more

A

red

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98
Q

what is the simplest way to find an unknown pH

A

use indicator paper

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99
Q

what is pH paper

A

paper soaked in universal indicator and then dried.

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100
Q

acid definition

A

a substance that dissolves in water to produce hydrogen ions (H+)

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101
Q

what is the formula for hydrochloric acid

A

HCl

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102
Q

what is the formula for nitric acid

A

HNO3

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103
Q

what is the formula for sulfuric acid

A

H2SO4

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104
Q

base definition

A

substances that neutralize acids by combining with the hydrogen ions in them/

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105
Q

alkali definition

A

bases that dissolve in water to form hydroxide ions.

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106
Q

examples of alkalis

A

sodium hydroxide

potassium hydroxide

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107
Q

salt definition

A

the compound formed when the hydrogen ions in an acid are replaced by either a metal ion or by an ammonium ion

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108
Q

what is oxidation

A

when an atom or a molecule loses an electron in a reaction

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109
Q

what is reduction

A

when an atom or a molecule gains an electron in a reaction

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110
Q

what does halogen mean

A

salt producing

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111
Q

what are halogens

A

non-metallic elements with diatomic molecules

112
Q

trend in melting and boiling points in group 7

A

they increase down the group because the relative molecular mass increases

113
Q

what structure do halogens have

A

covalent molecular

114
Q

are halogens good conductors of heat and electricity

A

no they are non metals

115
Q

which element would you necer find in a school lab due to its dangerous reactivity

A

fluorine

116
Q

when halogens react with hydrogen what do they form

A

hydrogen halide

117
Q

describe hydogen halides

A

they are all acidic, poisonous gases that are covalently bonded. theyre very soluble inwater and react with it to produce solutions of acids.

118
Q

when halogens react with alkali metals what do they form

A

salts

119
Q

trend of reactivity in the halogens

A

it decreases as you go down the group

120
Q

if something is more reactive,

A

it has more tendency to react to form a compound and displace the other element

121
Q

what is a spectator ion

A

e.g. the metal ion that doesn’t do anything in a displacement reaction

122
Q

does an ionic equation include spectator ions

A

no

123
Q

recution is

A

loss of oxygen

124
Q

oxidation is

A

losing electrons (sometimes through combining with oxygen which takes the electrons)

125
Q

why does reduction and oxidation happen at the same time

A

beacause if something loses oxygen, something else must gain it

126
Q

what is an oxidising agent

A

something that oxidises something else by taking oxygen away from it

127
Q

what is a reducing agent

A

something that reduces something else by giving electrons to it

128
Q

when are electrons attracted more strongly to the nucleus

A

when theyre closer

129
Q

as you move down the group what changes in the states if matter

A

it goes from gases to liquid to solid

130
Q

what do halogens have that get darker down the group

A

colourd poisonous vapours

131
Q

when halogens react with metals what forms

A

ionic salt

132
Q

when halogens react with non metals what forms

A

non-metals

133
Q

properties of astatine

A 
very dark grey or black
solid at room temp and high melting point
diatomic
less reactive than iodine
displaced by iodine
134
Q

how much nitrogen is in the air

A

78%

135
Q

how much oxygen is in the air

A

21%

136
Q

how much argon is in the air

A

0.9%

137
Q

how much carbon dioxide is in the air

A

0.04%

138
Q

how would you find the percentage of oxygen in the air

A

have two gas cylinders with a silica tube packed with copper filings between them. fill them to 100cm cubed collectively, then heat teh silica tube strongly. as the copper turns black as copper oxide forms, the oxygen is consumed, so there will be no change in volume anymore pushing the plungers back and forth. let cool and it will show that the volume of oxygen will have decreased.. then work out the volume of oxyegn recated, and the percentage of oxygen in the air.

139
Q

how would you determine how much oxugen there is in the ari using the rusting of iron

A

use a connecting ub between a gas syringe and conical flask containing wet iron filings. record the inital reading on the gas syringe, then leave it for about a week until the reading stops changing. record the final reading and calculate the percentage of oxxygen used.

140
Q

what could go wrong when using a practical to calculate th percentage of oxygen in the air

A

the experiment was not set up for long enough. the iron has not had enough chance to react with all the oxygen in the apparatus.
not enough iron was added at the beginning. it must be in excess, so there is enough iron to react with all the oxygen present.

141
Q

how would you find the percentage of oxygen in air by using phosphorus

A

put a piece of phosphorus in an evaporating basin floating in a water trough surrounded by a bell jar. mark the inital level of water. remove the bung and touch the phosphorus witha hot metaal wire to ignite it. replace the bunga nd wait untl the white smoke that forms (phosphorus oxide) clears. when the water level stops rising, mark it. then calcualte the percentage using how much oxygen was used up.

142
Q

what does magnesium burn in oxygen to give

A

a white, powdery ash of magnesium oxide

143
Q

what does sulfur burn in oxygen to give

A

poisonous, colourless suflur dioxide gas of sulfur dioxide

144
Q

how do you test for hydrogen

A

squeaky pop

145
Q

properties of metal oxides

A

ionic compounds containg O 2-
usually basic oxides, so they react with acids to form salts
usually insoluble in water. those that are soluble react with warer to form alkaline solutions containing hydroxide ions

146
Q

properties of non metal oxides

A

covalent compounds
acidic oxides
non metal oxides often soluble in water and react with it to form aidic solutions containing H + ions

147
Q

how can carbon dioxide be obtained

A

through the reaction of hydrochloric acid and calcium carbonate or when metal carnonates are heated strongly

148
Q

when is carbon dioxide produced

A

when fossil fuels burn

149
Q

when does the greenhouse effect occur

A

when high energy UV and visible light from the sum pass througn the atmoshpher and warm up the surface of the earth. the infrared radiation radiated by the earth is absorbed by CO2 molecules in the atmoshoere. they then give out this energy in all directions, heating the atmosphere.

150
Q

what does the pH scale tell you

A

how acidic or alkaline a solution is

151
Q

part of the PH scale that is strongly acidic

A

0-3

152
Q

universal indicator paper

A

a mixture of indicators which change colour in a gradual way. can be a solution or paper. ranges through a variety of colours form pH 1 to pH 14 but isnt very accurate

153
Q

what can be used as an indicator

A

anything that has different colours depending on the pH

154
Q

what colour is litmus in acid and alkaline solutions

A

red in acidic solutions an blued in alkaline, and purple in neutral

155
Q

what colour is universal indicator in neutral solutions

A

green

156
Q

what do all acids contain

A

hyrdogen

157
Q

what do you measure when you measure pH

A

the H+ ions

158
Q

what happens when acids are placed in water

A

they dissociate (break apart) to form hydrogen ions

159
Q

define acids

A

substances that act as a source of hydrogen ions in solution.

160
Q

what is a base

A

a substance that neutralises an acid by combining it with the hydrogen ions in them.

161
Q

what happens when a base dissolves inwater to form solutions

A

it contins hydroxide ions and are alkalis.

162
Q

define alkalis

A

a surce of hydroxide ions (OH - ions) in solution

163
Q

what do acids react with in a neutralisation reaction

A

bases or alkalis

164
Q

why will all neutralisation reactions have the same equation

A

they all involve the OH - ions from the alkali reacting with the H + ions from the acid ro form water

165
Q

purpose of titrations

A

to find out how much of the acid/alkali reacts with a certian volume of the alkali/acid.

166
Q

how do you carry out a titration

A

(rough titration first or now)
measure 25cm cubed of HCl using a pipette. transfer to conical flask. fill the burette with sodium hydroxide solution. take initial reading and record to 2 decimal places. add a few drops of phenolphthalein indicator. add sodium hydroxide until the indicator changes colour and then take the final reading on the burette when its a permanent pale pink colour

167
Q

how do you calculate the volume of alkali added in a titration

A

subtract the inital reading on the burette from the final reading on the burette

168
Q

why do you not use universal indicator in a titration

A

because it has a range of colours and changes gradually between them, so we could not see a clear endpoint.

169
Q

when you replace the hydrogen in an acid with a metal what do you form

A

a salt

170
Q

what are the name of salts formed from HCl

A

chlorides

171
Q

what are the name of salts formed from HNO 3

A

nitrates

172
Q

what are the name of salts formed from H2SO4

A

sulfates

173
Q

what are the name of salts formed from CH3COOH

A

ethanoates

174
Q

what are the name of salts formed from K3PO4

A

phosphates

175
Q

the higher a metal is in the reactivity series…

A

the more vigorous the reaction.

176
Q

(above hydrogen in the reactivity series) metal + acid =

A

salt + hydrogen

177
Q

metals below hydrogen in the series…

A

dont react with dilute acids

178
Q

magnesium with sulfuric/hydrochloric acid

A

rapid fizzing
colourless gas which pops with a lighted splint
reaction mixture becomes warmer
produces magnesium sulfate

179
Q

difference in reaction in xinc and acids

A

the only difference is its slower because zinc is lower down on the reactivity series

180
Q

metal oxide + acid =

A

salt + water

181
Q

metal hydroxide + acid =

A

salt + water

182
Q

neutralisaton reaction

A

OH- + H+ –> H2O

183
Q

carbonate + acid =

A

salt + carbon dioxide + water

184
Q

carbonataes react with cold dilute acids to

A

produce carbon dioxide gas.

185
Q

how do you recognise that green copper carboante reacts with common dilute acids

A

carbon dioxide is given off and it turns limewater milky.

186
Q

all sodium potassium and ammonium compounds are

A

soluble

187
Q

all nitrates are

A

soluble

188
Q

most common chlorides are

A

soluble except lead (II) chloride and silver chloride

189
Q

most common sulfates are

A

soluble except lead (II) sulfate, barium sulfate, silver sulfate and calcium sulfate

190
Q

most common carbonates are

A

insoluble except sodium, potassium and ammonium carbonates.

191
Q

most metal hydreoxides are

A

insoluble except sodium, potassium and ammonium hydroxides. calcium hydroxide is lightly soluble in water.

192
Q

how do you make soluble salts (except sodium, potassium, ammonium)

A

acid + metal (only for magnesium to iron)
acid + metal oxide or hydroxide
acid + carbonate

193
Q

making copper sulfate crystals

A

heat 50cm cubed of dilute sulfuric acid into a beaker and heat it on a tripod and gauze using a bunsen burner.
add a spatula full of black copper oxide and continue heating. stir well to make sure no more will react. (excess copper oxide, when there is some left, we know all the acid has been neutralised)
filter off excess copper oxide and transfer the filtrate to a evaporating basin. heat to boil off some water and to concentrate the solution. keep heating until saturated (dip a glass tod and if crystals form its saturated)
allow to cool at room temp for larger crystals.
filter
leave them to dry in a warm place

194
Q

why dont you evaporate the copper sulfate crystals

A

you would get anhydrous copper sulfate. this is water of crystallisation.

195
Q

when is a salt said to be hydrated

A

when it contains water of crystallisation,

196
Q

what is water of crystallisation

A

when water from the solution becomes chemically bound up with a salt

197
Q

making magnesuymn sulfate crystals

A

add magnesium to asulfuric acid. wait until fizzing stops. heat and allow to crystallise.

198
Q

how do you know whether to heat the mixture

A

carbonates and magnesium can react in the cold, everythin else needs heat

199
Q

why cant you make sodium, potassium, ammonium like this

A

theyre soluble in water

200
Q

making sodium sulfate crystals

A

25 cm cubed of sodium hydroxide is transferred to a conical flask using a pipette and a few drops of methyl orange.
dilute sulfuric acid is run in from the burette until the indicator just turns from yellow to orange.
colume of acid needed is noted, and the same volumes of cid and alkali are mixed in a clean flask with NO indicator
this is heataed to evaporate off some of the water until a saturated solution is formed. it is then left to for cool for crystals.
filtration
left to dry in warm place

201
Q

making sodium chloride crystals

A

do a titration with dilute HCl not dilute sulfuric acid, and then use the same procedure as sodium sulfate

202
Q

how do you make insoluble salts

A

mix two soluble salts to form an insoluble salt and a solution of a soluble one. this is a PRECIPITATION REACTION

203
Q

what is a precipitate

A

a solid formed by a chemical reaction involving liquids and gases

204
Q

what do we mix to form an insoluble salt

A

the nitrate of the metal part and the sodium/potassium of the non-metal part

205
Q

if the salt is soluble but not a sodium, potassium, ammonium salt how do you make it

A

react an acid with an excess of a solid metal (if suitably reactive) metal poxide, hydroxide or carbonatae

206
Q

if the salt is soluble and a sodium, potassium, ammonium salt how do tou make it

A

use a titration method. react an acid with a solution of sodium, potassium hydroxide or carbonate (or use ammonia solution)

207
Q

if the salt is insoluble how do you make it

A

use precipitation method. mix two solutions, one contianing the correct pos ion and one the correct neg ion

208
Q

an acid is

A

a proton (hydrogen ion) doner

209
Q

a base is

A

a proton (hydrogen ion) acceptor

210
Q

test for oxygen gas

A

a glowing splint is put into the tube containing the gas. oxygen will erlight it.

211
Q

test for CO2

A

the carbon dioxide is bubbled through limewater. carbon dioxide turns limewater milky.

212
Q

whats limewater

A

a calcium hydroxide solution. CO2 reacts with it to form a white precipitate of calcium carbonate

213
Q

test for chlorine gas

A

damp litmus paper or universal indicator paper put in/held over mouth of test tube. chlorine will bleach the papers

214
Q

test for ammonia

A

turns damp universla indicator paper or red litmus paper blue

215
Q

water turns anhydrous copper sulfate

A

blue

216
Q

physical test for purity of water

A

does it freeze at 0 or boil at 100

217
Q

what is a flame test used for

A

to show the presence of cations

218
Q

describe the preciptation method for making salts

A

combine two solutions containing the necessary positive and negative ions

219
Q

describe the excess base method for making salts

A

react an acid with an excess of a metal (if suitably reactive) , metal oxide, metal hydroxide or metal carbonate and then fliter

220
Q

does reactivity increase or decrease as you go down the alkali metals

A

increase

221
Q

what makes an element reactive

A

the ability of it to lose electrons. if it loses an electron easily, it is more reactive

222
Q

what factor contributes to an element’s reactivity

A

how strongly the electron is attracted to the nucleus of the atom.

223
Q

how does the nucelus attract electrons

A

the nucleus is positive due to the charge of protons, and so it can attract negative electrons

224
Q

why does reactitivty increase down the alkali metals

A

the electrons are further away from the centre/nucleus of the atom so the attaction between the oppositely charged electron and nucleus is weaker, allowing it to be lost more easily.

225
Q

why does reactivity decrease down the halogens

A

because the electrons are further away from the centre/nucleus of the atom so the attraction between the oppositely charged electron and nucleus is weaker, meaning it cannot attract or gain electrons as easily.

226
Q

why is carbon included in the reactivity series

A

its important in extracting several metals from metal oxides.

227
Q

what happens if you heat carbon with a less reactive metal

A

it can be a cheap way of removing oxygen from the oxide to leave the metal.

228
Q

why does an oxidising agent always get reduced

A

it oxidises something else by giving away oxygen

229
Q

why can’t you just evaporate off all water to gain copper sulfate crystals

A

you would get white anhydrous copper sulfate not blue copper sulfate crystals

230
Q

why can’t you use the method for making soluble salts for sodium potassium and ammonium

A

they are soluble in water so they would not react with the acid but issolve.

231
Q

what method can you use to make sodium, potassium and ammonium salts

A

use a titration to neutralise them

232
Q

how do you make sodium potassium and ammonium salts

A

titration
(acid run from beaker until indicator changes)
volume of acid needed is noted, and same volumes of acid and alkali are mixed together in a beaker without indicator
solution is heated to evaporate off some of it and until a saturated solution forms. it is left to cool for crystals.
the crystals are separated by filtration
then are dried by patting them dry with a paper towel or by leaving them in a warm place.

233
Q

what is a precipitation reaction

A

where two soluble salts are mixed to form an insoluble salt and a solution of a soluble one. it forms a precipitate

234
Q

what is a precipitate

A

a solid that is formed by a chemical reaction involving liquids or gases.

235
Q

how does a precipitation reaction work

A

one solution has ions that are attracted to eachother but not very strongly, and when mixed with another solution, are far more attracted to one of the ions in it, and clump together tightly to form a solid or precipitate.

236
Q

how do yo u know what to mix to create an insolubel salt

A

the nitrate of the metal part of the insoluble salt, and the sodium/potassium part of the non-metal.

237
Q

the salt isn’t soluble so…

A

use a precipitation reaction

238
Q

the salt is soluble but it is not a sodium/potassium/ammonium salt so…

A

react an acid with an excess of a solid metal (if suitably reactive), metal oxide, hydroxide or carbonate.

239
Q

the salt is soluble and is a sodium/potassium/ammonium salt so…

A

use a titration method. react an acid with a solution of sodium or potassium hydroxide or carbonate.

240
Q

what is an ore

A

a sample of rock that contains enough of a mineral for it to be worthwhile to extract the metal

241
Q

where are most ores extracted from

A

the earths crust

242
Q

which metals are found native and what does this mean

A

they exist naturally as the uncombined element, like gold (or silver or copper)

243
Q

most metals are found in the earths crust combined with other elements. what are the indiviual compounds called

A

minerals

244
Q

what is roasting

A

the proccess of converting into an oxide by heating in air

245
Q

how do you obtain the metal from the oxide and what is this called

A

remove the oxygen, and reduction

246
Q

what is the main reducing agent for metals below carbon in the reactivity series

A

carbon monoxide

247
Q

why can’t metals higher than zinc be reduced by carbon at reasonable temperatures

A

the metals aremove reactive than carbon and therefore carbonc annot take the oxygen away from themetal oxide.

248
Q

what are metals above zinc usually produced by

A

electrolysis

249
Q

what molten salt does aluminium oxide dissolve in

A

cryolite

250
Q

why is aluminium oxide dissolved in cryolite

A

it makes the process more economical as opposed to over 2000 degrees, the process can now be carried out at 1000 degrees

251
Q

where does the cathode typically go in extraction of metals via electrolysis

A

as the lining

252
Q

where does the anode typically go in extraction of metals via electrolysis

A

as the electrodes inserted at the top

253
Q

why is electrolysis expensive

A

it requires a lot of energy

254
Q

what is an alloy

A

a mixture of a metal ususally with other metals or carbon.

255
Q

why are alloys harder than the metals from which they are originally made

A

the different metals/elements have slightly different sized atoms. this breaks up the regular lattice arrangement and makes it more difficult for the layers of ions to slide over eachother.

256
Q

uses of aluminium (alloys)

A

planes, electricity cables, pots and pans

257
Q

what do metals’ uses depend on

A

(low) density and strength

258
Q

why does aluminium resist corrosion

A

because it has a thin but strong layer of aluminium oxide on the surface, which prevents anything reaching the surface and reacting with it.

259
Q

what is mild steel

A

the name given to an alloy or iron contianing up to about 25% carbon

260
Q

characteristics of mild steel

A

strong material that can be easily hammered into various shapes (malleable) and drawn into wires (ductile).

261
Q

what can mild steel be used for

A

nails, car bodies, ship building, girders and bridges

262
Q

disadvantage of mild steel

A

it rusts when exposed to oxygen and water

is three times denser than aluminium

263
Q

advantage of car bodies being made of aluminium

A

lighter, so less fuel is needed.

264
Q

what is high carbon steel

A

contains 0.6-1.2% carbon, and a little manganese

265
Q

characteristics of high carbon steel

A

harder and more resistant to wear than mild steel but more brittle. (not as malleable and ductile).

266
Q

what is high carbon steel used for

A

cutting tools like knives

267
Q

what is stainless steel

A

an alloy of iron with chromium and often nickel.

268
Q

characteristics of stainless steel

A

the chromium forms a strong oxide layer like aluminium and this oxide layer protects the iron as well, so it is very resistant to corrosion.

269
Q

what is stainless steel used for

A

kitchen sinks, saucepans, knives and forks, gardening tools, brewing, dariy and chemical industries

270
Q

which type of steel is most expensive

A

stainless steel

271
Q

properties of electrical wires made of copper and alloys

A

very good conductor of electricity and ductile

272
Q

properties of pots and pans made of copper and alloys

A

very good conductor of heat, very unreactive and malleable

273
Q

properties of water pipes made of copper and alloys

A

unreactive, does not react with hot or cold water and malleable

274
Q

surfaces in hospitals

A

antimicrobial properties and malleable

275
Q

what is mixed with iron when it is being extracted

A

coke

limestone

276
Q

what is the outside of a blast furnace made of

A

steel lined heat resistant rock

edexcel igcse chemistry (4 decks)

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