unit two: inorganic chemistry Flashcards
(276 cards)
1
Q
what are the group one metals called
A
alkali metals
2
Q
what are lithium, sodium and potassium stored in and why?
A
oil to prevent them from reacting with oxygen and water.
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
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.
5
Q
what does lithium, sodium and potassium form when they burn in air
A
white solid oxides
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
7
Q
what colour flame does lithium burn with
A
red
8
Q
what colour flame does sodium burn with
A
yellow
9
Q
what colour flame does potassium burn with
A
lilac
10
Q
do lithium sodium and potassium react with water
A
yes vigorously
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
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
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
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
15
Q
order of reactivity of lithium, sodium and potassium
A
potassium - sodium - lithium (more reactive with increasing atomic number)
16
Q
what happens involving reactivity as you move down group 1
A
reactivity of the elements increases
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.
18
Q
physical state and colour of chlorine at room temperature
A
pale green gas
19
Q
physical state and colour of bromine at room temperature
A
red-brown liquid
20
Q
physical state and colour of iodine at room temperature
A
black solid
21
Q
what happens when chlorine reacts with iron
A
brown smoke is formed and a brown solid is left behind
22
Q
what happens when bromine reacts with water
A
bromine smoke and a brown solid are formed
23
Q
what happens when iodine reacts with water
A
brown smoke and a brown solid are formed
24
Q
what is a halide
A
a compound of a halogen and one other element
25
whats in a metal halide
a compounf of a halogen and a metal
26
what happens when chlorine reacts with hydrogen
explosion when exposed to UV radiation
27
what happens when bromine reacts with hydrogen
the vapour formed will react when heated
28
what happens when iodine reacts with hydrogen
the vapour will react when heated, but the reaction does not go to completion
29
when is a metal halide formed
e.g. when a halogen is reacted with iron
30
when is a hydrogen halide formed
e.g. when a halogen is reacted with hydrogen
31
general rule for displacement reactions
a halogen will displace a less reactive halogen for an aqeous solution of its halide.
32
what colour is aqueous chlorine
very pale green, usually diluted to colourless
33
what colour is aqueous bromine
orange but will turn yellow when diluted.
34
what colour is aqueous iodine
brown
35
in displacement reactions, the halogen molecule is often being reduced because
it is gaining electrons
36
in displacement reactions, the halide ions are being oxidised because
they are losing electrons
37
when both reduction (of a halogen) and oxidisation (of a halide) is happening the reaction is called a
redox reaction
38
why does reactivity decrease down the group of halogens
the increasing size of the atom means it will be harder for the atom to quickly gain an electron
39
what percentage of air is nitrogen
78%
40
what percentage of air is oxygen
21%
41
what percentage of air is argon
0.9%
42
what percentage of air is carbon dioxide
0.04%
43
how would you measure the oxygen content of air using copper
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.
44
what would the results be after measuring the oxygen content of air using copper
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.
45
how would you measure the oxygen content of air using iron
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.
46
how would you measure the oxygen content of air using phosphorus
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.
47
observations of magnesium when it burns in oxygen
bright white flame to form a white powder
48
observations of carbon when it burns in oxygen
yellow-orange flame to form a colourless gas.
49
observations of sulfur when it burns in oxygen
blue flame to form a colourless gas
50
describe magnesium oxide
basic oxide, slightly soluble in water and a pH of about 10. reacts with water to form magnesium hydroxide
51
describe carbon and sulfur dioxide
acidic oxides, dissolve in water to form acidic solutions.
52
the reaction between any metal carbonate and an acid will produce
carbon dioxide
53
when metal carbonates are heated what is produced
carbon dioxide
54
observations of the thermal decompisition of copper carbonate
green copper carbonate and black copper oxide are heated, and if carbon dioxide is produced the limewater attacahed to it will turn milky
55
observations of the thermal decompisition of magnesium carbonate
no change, stays white
56
observations of the thermal decomposition of calcium carbonate
no change stays white
57
observations of the thermal decomposition of zinc carbonate
white to yellow when hot and white again when cold
58
observations of the thermal decomposition of sodium carbonate
no observable change, stays white
59
how does production of carbon dioxide enhance the greenhouse effect
more heat is re-emitted by the atmosphere and less heat escapes into space .
60
effects of global warming
polar ice caps melt, sea levels rise, more extreme weather
61
list the reactivity series
```
potassium
sodium
lithium
calcium
magneisum
aluminium
zinc
iron
tin
lead
copper
silver
gold
platinum
```
62
reducing metal oxides
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.
63
(reactivity series) the substance that carries out the reduction is called the
reducing agent
64
why is hydrogen in the reactivity series
although not a metal, it can be displaced from an aquous solution like a metal, only this time, the solution is an acid.
65
where is carbon in the reactivity series
it can combine with oxygen to form carbon dioxide, between aluminium and zinc.
66
what is rusting
an oxidation reduction
67
the iron reacts with water and oxugen to form rust or?
hydrated iron (III) oxide
68
what is coating
stopping oxygen or water reaching the surface of the metal
69
examples of coating
oiling (bicycle chains)
greasing (nuts and bolts)
painting (car body panels)
70
what is alloying
stainless steel is an iron alloy that does not rust. used for sinks etc
71
what is sacrificial protection
attaching a more reactive metal such as magnesium slows down rusting.
72
what is plating
iron objects can be covered with a thin layer of metal.
73
examples of plating
food cans plated with tin
| buckets plated with zinc (also gives sacrifical protection.)
74
give the only two elements that occur as elements in their ores
silver and gold (most unreactive)
75
how can sulfides be easily converted into oxides
by roasting (heating in air)
76
how to extract metal from the first 6 metals in the reactivity series
electrolysis of the molten chloride or molten oxide
77
how to extract metal from the middle 3 metals in the reactivity series (zinc, iron, copper)
heat with a reducing agent such as carbon or carbon monoxide
78
how to extract metal from the last 2 metals in the reactivity series (silver, gold)
you don't, they occur naturally as elements
79
uses of aluminium
aeroplane bodies
saucepans
food cans
window frames
80
uses of iron
car bodies
iron nails
ships and bridges
81
why is aluminium and iron rarely used by themselves
they aren't very strong so aluminium alloys are usually used instead.
82
how can aluminium be stengthened
by adding other elements such as silicon, copper or magnesium.
83
what is pure iron also called
wrought iron
84
describe the structure of ions in a pure metal
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.
85
describe the structure of ions in an alloy
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.
86
which end of the pH scale is acidic
0-6 (decreasingly so)
87
which end of the pH scale is alkaline
8-14 (increasingly so)
88
which number on the pH scale is neutral
7
89
give an example of a neutral substance
pure water
90
what colour does litmus paper turn in a solution where the pH is 5 or less
red
91
what colour does litmus paper turn in a solution where the pH is 8 or more
blue
92
what colour does litmus paper turn in a solution between 5 and 8
a shade of purple (between red and blue)
93
what colour is methyl orange in a solution where the pH is 3 or less
red
94
what colour is methyl orange in a solution where the pH is 5 or more
yellow
95
what colour is methyl orange in a solution where the pH is between 3 and 5
orange (between red and yellow)
96
what colour is phenolphthalein in a solution where the pH is 8 or less
colourless
97
what colour is phenolphthalein in a solution where the pH is 10 or more
red
98
what is the simplest way to find an unknown pH
use indicator paper
99
what is pH paper
paper soaked in universal indicator and then dried.
100
acid definition
a substance that dissolves in water to produce hydrogen ions (H+)
101
what is the formula for hydrochloric acid
HCl
102
what is the formula for nitric acid
HNO3
103
what is the formula for sulfuric acid
H2SO4
104
base definition
substances that neutralize acids by combining with the hydrogen ions in them/
105
alkali definition
bases that dissolve in water to form hydroxide ions.
106
examples of alkalis
sodium hydroxide
| potassium hydroxide
107
salt definition
the compound formed when the hydrogen ions in an acid are replaced by either a metal ion or by an ammonium ion
108
what is oxidation
when an atom or a molecule loses an electron in a reaction
109
what is reduction
when an atom or a molecule gains an electron in a reaction
110
what does halogen mean
salt producing
111
what are halogens
non-metallic elements with diatomic molecules
112
trend in melting and boiling points in group 7
they increase down the group because the relative molecular mass increases
113
what structure do halogens have
covalent molecular
114
are halogens good conductors of heat and electricity
no they are non metals
115
which element would you necer find in a school lab due to its dangerous reactivity
fluorine
116
when halogens react with hydrogen what do they form
hydrogen halide
117
describe hydogen halides
they are all acidic, poisonous gases that are covalently bonded. theyre very soluble inwater and react with it to produce solutions of acids.
118
when halogens react with alkali metals what do they form
salts
119
trend of reactivity in the halogens
it decreases as you go down the group
120
if something is more reactive,
it has more tendency to react to form a compound and displace the other element
121
what is a spectator ion
e.g. the metal ion that doesn't do anything in a displacement reaction
122
does an ionic equation include spectator ions
no
123
recution is
loss of oxygen
124
oxidation is
losing electrons (sometimes through combining with oxygen which takes the electrons)
125
why does reduction and oxidation happen at the same time
beacause if something loses oxygen, something else must gain it
126
what is an oxidising agent
something that oxidises something else by taking oxygen away from it
127
what is a reducing agent
something that reduces something else by giving electrons to it
128
when are electrons attracted more strongly to the nucleus
when theyre closer
129
as you move down the group what changes in the states if matter
it goes from gases to liquid to solid
130
what do halogens have that get darker down the group
colourd poisonous vapours
131
when halogens react with metals what forms
ionic salt
132
when halogens react with non metals what forms
non-metals
133
properties of astatine
```
very dark grey or black
solid at room temp and high melting point
diatomic
less reactive than iodine
displaced by iodine
```
134
how much nitrogen is in the air
78%
135
how much oxygen is in the air
21%
136
how much argon is in the air
0.9%
137
how much carbon dioxide is in the air
0.04%
138
how would you find the percentage of oxygen in the air
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
how would you determine how much oxugen there is in the ari using the rusting of iron
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
what could go wrong when using a practical to calculate th percentage of oxygen in the air
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
how would you find the percentage of oxygen in air by using phosphorus
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
what does magnesium burn in oxygen to give
a white, powdery ash of magnesium oxide
143
what does sulfur burn in oxygen to give
poisonous, colourless suflur dioxide gas of sulfur dioxide
144
how do you test for hydrogen
squeaky pop
145
properties of metal oxides
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
properties of non metal oxides
covalent compounds
acidic oxides
non metal oxides often soluble in water and react with it to form aidic solutions containing H + ions
147
how can carbon dioxide be obtained
through the reaction of hydrochloric acid and calcium carbonate or when metal carnonates are heated strongly
148
when is carbon dioxide produced
when fossil fuels burn
149
when does the greenhouse effect occur
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
what does the pH scale tell you
how acidic or alkaline a solution is
151
part of the PH scale that is strongly acidic
0-3
152
universal indicator paper
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
what can be used as an indicator
anything that has different colours depending on the pH
154
what colour is litmus in acid and alkaline solutions
red in acidic solutions an blued in alkaline, and purple in neutral
155
what colour is universal indicator in neutral solutions
green
156
what do all acids contain
hyrdogen
157
what do you measure when you measure pH
the H+ ions
158
what happens when acids are placed in water
they dissociate (break apart) to form hydrogen ions
159
define acids
substances that act as a source of hydrogen ions in solution.
160
what is a base
a substance that neutralises an acid by combining it with the hydrogen ions in them.
161
what happens when a base dissolves inwater to form solutions
it contins hydroxide ions and are alkalis.
162
define alkalis
a surce of hydroxide ions (OH - ions) in solution
163
what do acids react with in a neutralisation reaction
bases or alkalis
164
why will all neutralisation reactions have the same equation
they all involve the OH - ions from the alkali reacting with the H + ions from the acid ro form water
165
purpose of titrations
to find out how much of the acid/alkali reacts with a certian volume of the alkali/acid.
166
how do you carry out a titration
(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
how do you calculate the volume of alkali added in a titration
subtract the inital reading on the burette from the final reading on the burette
168
why do you not use universal indicator in a titration
because it has a range of colours and changes gradually between them, so we could not see a clear endpoint.
169
when you replace the hydrogen in an acid with a metal what do you form
a salt
170
what are the name of salts formed from HCl
chlorides
171
what are the name of salts formed from HNO 3
nitrates
172
what are the name of salts formed from H2SO4
sulfates
173
what are the name of salts formed from CH3COOH
ethanoates
174
what are the name of salts formed from K3PO4
phosphates
175
the higher a metal is in the reactivity series...
the more vigorous the reaction.
176
(above hydrogen in the reactivity series) metal + acid =
salt + hydrogen
177
metals below hydrogen in the series...
dont react with dilute acids
178
magnesium with sulfuric/hydrochloric acid
rapid fizzing
colourless gas which pops with a lighted splint
reaction mixture becomes warmer
produces magnesium sulfate
179
difference in reaction in xinc and acids
the only difference is its slower because zinc is lower down on the reactivity series
180
metal oxide + acid =
salt + water
181
metal hydroxide + acid =
salt + water
182
neutralisaton reaction
OH- + H+ --> H2O
183
carbonate + acid =
salt + carbon dioxide + water
184
carbonataes react with cold dilute acids to
produce carbon dioxide gas.
185
how do you recognise that green copper carboante reacts with common dilute acids
carbon dioxide is given off and it turns limewater milky.
186
all sodium potassium and ammonium compounds are
soluble
187
all nitrates are
soluble
188
most common chlorides are
soluble except lead (II) chloride and silver chloride
189
most common sulfates are
soluble except lead (II) sulfate, barium sulfate, silver sulfate and calcium sulfate
190
most common carbonates are
insoluble except sodium, potassium and ammonium carbonates.
191
most metal hydreoxides are
insoluble except sodium, potassium and ammonium hydroxides. calcium hydroxide is lightly soluble in water.
192
how do you make soluble salts (except sodium, potassium, ammonium)
acid + metal (only for magnesium to iron)
acid + metal oxide or hydroxide
acid + carbonate
193
making copper sulfate crystals
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
why dont you evaporate the copper sulfate crystals
you would get anhydrous copper sulfate. this is water of crystallisation.
195
when is a salt said to be hydrated
when it contains water of crystallisation,
196
what is water of crystallisation
when water from the solution becomes chemically bound up with a salt
197
making magnesuymn sulfate crystals
add magnesium to asulfuric acid. wait until fizzing stops. heat and allow to crystallise.
198
how do you know whether to heat the mixture
carbonates and magnesium can react in the cold, everythin else needs heat
199
why cant you make sodium, potassium, ammonium like this
theyre soluble in water
200
making sodium sulfate crystals
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
making sodium chloride crystals
do a titration with dilute HCl not dilute sulfuric acid, and then use the same procedure as sodium sulfate
202
how do you make insoluble salts
mix two soluble salts to form an insoluble salt and a solution of a soluble one. this is a PRECIPITATION REACTION
203
what is a precipitate
a solid formed by a chemical reaction involving liquids and gases
204
what do we mix to form an insoluble salt
the nitrate of the metal part and the sodium/potassium of the non-metal part
205
if the salt is soluble but not a sodium, potassium, ammonium salt how do you make it
react an acid with an excess of a solid metal (if suitably reactive) metal poxide, hydroxide or carbonatae
206
if the salt is soluble and a sodium, potassium, ammonium salt how do tou make it
use a titration method. react an acid with a solution of sodium, potassium hydroxide or carbonate (or use ammonia solution)
207
if the salt is insoluble how do you make it
use precipitation method. mix two solutions, one contianing the correct pos ion and one the correct neg ion
208
an acid is
a proton (hydrogen ion) doner
209
a base is
a proton (hydrogen ion) acceptor
210
test for oxygen gas
a glowing splint is put into the tube containing the gas. oxygen will erlight it.
211
test for CO2
the carbon dioxide is bubbled through limewater. carbon dioxide turns limewater milky.
212
whats limewater
a calcium hydroxide solution. CO2 reacts with it to form a white precipitate of calcium carbonate
213
test for chlorine gas
damp litmus paper or universal indicator paper put in/held over mouth of test tube. chlorine will bleach the papers
214
test for ammonia
turns damp universla indicator paper or red litmus paper blue
215
water turns anhydrous copper sulfate
blue
216
physical test for purity of water
does it freeze at 0 or boil at 100
217
what is a flame test used for
to show the presence of cations
218
describe the preciptation method for making salts
combine two solutions containing the necessary positive and negative ions
219
describe the excess base method for making salts
react an acid with an excess of a metal (if suitably reactive) , metal oxide, metal hydroxide or metal carbonate and then fliter
220
does reactivity increase or decrease as you go down the alkali metals
increase
221
what makes an element reactive
the ability of it to lose electrons. if it loses an electron easily, it is more reactive
222
what factor contributes to an element's reactivity
how strongly the electron is attracted to the nucleus of the atom.
223
how does the nucelus attract electrons
the nucleus is positive due to the charge of protons, and so it can attract negative electrons
224
why does reactitivty increase down the alkali metals
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
why does reactivity decrease down the halogens
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
why is carbon included in the reactivity series
its important in extracting several metals from metal oxides.
227
what happens if you heat carbon with a less reactive metal
it can be a cheap way of removing oxygen from the oxide to leave the metal.
228
why does an oxidising agent always get reduced
it oxidises something else by giving away oxygen
229
why can't you just evaporate off all water to gain copper sulfate crystals
you would get white anhydrous copper sulfate not blue copper sulfate crystals
230
why can't you use the method for making soluble salts for sodium potassium and ammonium
they are soluble in water so they would not react with the acid but issolve.
231
what method can you use to make sodium, potassium and ammonium salts
use a titration to neutralise them
232
how do you make sodium potassium and ammonium salts
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
what is a precipitation reaction
where two soluble salts are mixed to form an insoluble salt and a solution of a soluble one. it forms a precipitate
234
what is a precipitate
a solid that is formed by a chemical reaction involving liquids or gases.
235
how does a precipitation reaction work
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
how do yo u know what to mix to create an insolubel salt
the nitrate of the metal part of the insoluble salt, and the sodium/potassium part of the non-metal.
237
the salt isn't soluble so...
use a precipitation reaction
238
the salt is soluble but it is not a sodium/potassium/ammonium salt so...
react an acid with an excess of a solid metal (if suitably reactive), metal oxide, hydroxide or carbonate.
239
the salt is soluble and is a sodium/potassium/ammonium salt so...
use a titration method. react an acid with a solution of sodium or potassium hydroxide or carbonate.
240
what is an ore
a sample of rock that contains enough of a mineral for it to be worthwhile to extract the metal
241
where are most ores extracted from
the earths crust
242
which metals are found native and what does this mean
they exist naturally as the uncombined element, like gold (or silver or copper)
243
most metals are found in the earths crust combined with other elements. what are the indiviual compounds called
minerals
244
what is roasting
the proccess of converting into an oxide by heating in air
245
how do you obtain the metal from the oxide and what is this called
remove the oxygen, and reduction
246
what is the main reducing agent for metals below carbon in the reactivity series
carbon monoxide
247
why can't metals higher than zinc be reduced by carbon at reasonable temperatures
the metals aremove reactive than carbon and therefore carbonc annot take the oxygen away from themetal oxide.
248
what are metals above zinc usually produced by
electrolysis
249
what molten salt does aluminium oxide dissolve in
cryolite
250
why is aluminium oxide dissolved in cryolite
it makes the process more economical as opposed to over 2000 degrees, the process can now be carried out at 1000 degrees
251
where does the cathode typically go in extraction of metals via electrolysis
as the lining
252
where does the anode typically go in extraction of metals via electrolysis
as the electrodes inserted at the top
253
why is electrolysis expensive
it requires a lot of energy
254
what is an alloy
a mixture of a metal ususally with other metals or carbon.
255
why are alloys harder than the metals from which they are originally made
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
uses of aluminium (alloys)
planes, electricity cables, pots and pans
257
what do metals' uses depend on
(low) density and strength
258
why does aluminium resist corrosion
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
what is mild steel
the name given to an alloy or iron contianing up to about 25% carbon
260
characteristics of mild steel
strong material that can be easily hammered into various shapes (malleable) and drawn into wires (ductile).
261
what can mild steel be used for
nails, car bodies, ship building, girders and bridges
262
disadvantage of mild steel
it rusts when exposed to oxygen and water
| is three times denser than aluminium
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advantage of car bodies being made of aluminium
lighter, so less fuel is needed.
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what is high carbon steel
contains 0.6-1.2% carbon, and a little manganese
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characteristics of high carbon steel
harder and more resistant to wear than mild steel but more brittle. (not as malleable and ductile).
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what is high carbon steel used for
cutting tools like knives
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what is stainless steel
an alloy of iron with chromium and often nickel.
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characteristics of stainless steel
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.
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what is stainless steel used for
kitchen sinks, saucepans, knives and forks, gardening tools, brewing, dariy and chemical industries
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which type of steel is most expensive
stainless steel
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properties of electrical wires made of copper and alloys
very good conductor of electricity and ductile
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properties of pots and pans made of copper and alloys
very good conductor of heat, very unreactive and malleable
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properties of water pipes made of copper and alloys
unreactive, does not react with hot or cold water and malleable
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surfaces in hospitals
antimicrobial properties and malleable
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what is mixed with iron when it is being extracted
coke
| limestone
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what is the outside of a blast furnace made of
steel lined heat resistant rock
