Metals Flashcards
what are properties of metals?
- malleable
- ductile
- high density
- high MP BP
- good conductors of heat and electricity
what does malleable mean?
can be easily beaten into fine wires without breaking
what does ductile mean?
can be stretched into fine wires without breaking
why are metals malleable and ductile?
their atoms are of the same size and are arranged in orderly layers. so layers can slide over each other easily when a force is applied
why do metals have high density?
as their metal atoms are closely packed together
why do metals have high melting and boiling points?
as their metal atoms are packed tightly in layers by strong metallic bonds. a lot of energy is needed to break the strong metallic bonds
why are metals good conductors of heat and electricity?
as they have a sea of delocalised mobile electrons that can carry charges
what are alloys?
a mixture of metals with one or more elements
what is bronze made of?
copper and tin
what is steel made of?
iron and carbon
what is steel used for?
car bodies and machinery
what is stainless steel made of?
iron, carbon and small amounts of chromium and nickel
what is stainless steel used for?
cutlery, utensils and surgical instruments
what is brass made of?
copper and zinc
what is brass used for?
coins and musical instruments
what is the structure of metals?
- pure metals are weak and soft
- atoms of the same size and are arranged in regular layers which slide over easily when force is applied
- soft and malleable
what is the structure of alloys?
- hard and strong
- different sizes of atoms disrupt regular and orderly arrangements of atoms
- difficult for atoms in an alloy to slide over each other when force is applied
- stronger and less malleable than pure metals
what is the product of the reaction between metal and water?
metal hydroxide and hydrogen
what is the product of the reaction between metal and steam?
metal oxide and hydrogen
what is the product of the reaction between metal and acids?
salt and hydrogen
what is the reactivity series of metals?
potassium sodium calcium magnesium aluminium zinc iron tin lead copper mercury silver gold
where is carbon?
in between aluminium and zinc
where is hydrogen?
in between lead and copper
what metals react with cold water, steam and acid?
3
potassium, sodium and calcium
what metals react with steam and acid?
4
magnesium, aluminium, zinc and iron
what metals react with acid?
2
tin and lead
what metals are unreactive?
4
copper, mercury, silver and gold
what metals can be extracted by electrolysis?
5
potassium to aluminium
what metals can be extracted by heating with carbon?
zinc to gold
what metals can be extracted by heating with hydrogen?
last 4 metals
what is needed in the extraction of iron?
hematite, coke and limestone
what is the first extraction of iron equation and what does it do?
C + O2 -> CO2
production of carbon monoxide from burning coke in hot air
what is the second extraction of iron equation and what does it do?
CO2 + C -> 2CO
production of carbon monoxide through the reaction of carbon dioxide with coke
what is the third extraction of iron equation and what does it do?
3CO + Fe2O3 -> 2Fe +3CO2
reduction of iron (III) oxide by carbon monoxide reducing iron (III) oxide to iron
what is the first equation in the removal of impurities and what does it do?
CaCO3 -> CaO + CO2
the decomposition of limestone
what is the second equation in the removal of impurities and what does it do?
Cao + SiO2 -> CaSiO3
the reaction of calcium oxide with silicon oxide which is a basic oxide and acidic oxide which forms slag
what metals rust?
iron and steel
what about other metals?
corrosion
what are the condition for rusting?
- air, oxygen
- water, dissolved salt speeds up rusting (seawater)
what are ways to prevent rusting?
- surface protection
- sacrificial protection
- galvanising
what are some examples of surface protection?
- painting on street poles
- oiling or greasing machinery
- coating with plastic on metal clips
- metal plating on food cana
explain sacrificial protection
- happens when a more reactive metal reacts in place of a less reactive metal
- the two metals must be touching each other
- for instance, when magnesium and iron are in touch with each other, magnesium reacts in place of iron, it ‘sacrifices’ itself for iron
explain galvanising
- happens when zinc is coated on top of a more reactive metal
- the zinc reacts in place of the more reactive metal and is used up instead of the more reactive metal
what is a practical application of galvanising?
zinc roofing
what is one way to conserving metals?
recycling
what is one way of recycling metals
using other materials in its place e.g glass bottles instead of metal cans
what are some benefits of recycling metals?
- conserves limited supply of metals
- saves costs of extracting new metals
- prevents land pollution from the careless disposition of metals
- recycling produces less pollution than extracting
what are some disadvantages of recycling metals?
- metals are only recycled if it’s economical to do so
- can cause air pollution from melting of scrap metal
- cost of separating metals from waste can be high
- costs money to collect scrap metals
- can be difficult to persuade people to deposit materials in recycling containers
