metals and alloys Flashcards
what are the 3 physical properties of metals
good conductor of heat and electricity
high density
high melting and boiling point
what are the characteristics of pure metals
malleable and ductile
atoms are of same size and arranged in neat layers
when force is applied, a layer of atoms can slide over each other easily
what are the characteristics of alloys
stronger and harder than a pure metal
atoms are of different sizes from different metals thus disrupts orderly arrangement
when force is applied, a layer of atoms cannot slide pat each other easily
define alloys
is a mixture of metals with other elements
why do we use alloys instead of metals
stronger and harder
more resistant to corrosion
improve the appearance of metals
lower melting points of metals
what are the 4 types of alloys
brass
bronze
steel
stainless steel
brass is made up of…
copper and zinc
bronze is made up of…
copper and tin
steel is made up of…
iron and carbon
stainless steel is made up of…
iron, carbon and chromium
brass is used to make…
musical instrument
bronze is used to make…
coins and sculptures
steel is used to make…
construct railways and buildings
stainless steel is used to make…
cutlery and surgical instruments
name all the elements in the reactive series
please stop calling me a crappy zebra, i (like) horses cow sheep and goat Potassium Sodium Calcium Magnesium Aluminium Carbon Zinc Iron Hydrogen Copper Silver Gold
which are the elements that use electrolysis for the methods of extraction
P - A Potassium Sodium Calcium Magnesium Aluminium
which of the elements that are used for extraction
carbon
which are the elements that use extraction of metals using carbon
Z - S Zinc Iron Hydrogen Copper Silver
which element is found uncombined
Gold
which elements react with acid
P - H Potassium Sodium Calcium Magnesium Aluminium Carbon Zinc Iron Hydrogen
which elements do not react with acid
C - G
Copper
Silver
Gold
which elements react with cold water
P - M Potassium Sodium Calcium Magnesium
which elements do not react with cold water
A - G Aluminium Carbon Zinc Iron Hydrogen Copper Silver Gold
which elements react with steam
M - G Magnesium Aluminium Carbon Zinc Iron Hydrogen Copper Silver Gold
which elements are too dangerous to react with steam
P - C
Potassium
Sodium
Calcium
which elements do not react with steam
C - G Carbon Zinc Iron Hydrogen Copper Silver Gold
what is displacement of metals
a more reactive metal displaces a less reactive metal from its solution
what are the reactants used to extract pure metals from their metal ores using blast furnace
limestone
haematite
coke
hot air
what are the products when extracting pure metals from their metal ores using blast furnace
waste gases
slag
molten _____ (iron etc)
what is the function of limestone
to remove acidic impurities
what are waste gases formed
78% of nitrogen
carbon dioxide
what are the 4 stages of the process the reactants went through
- produce carbon dioxide
- produce carbon dioxide
- reduce haematite to produce molten ____ (iron etc)
- remove acidic impurities, silicon dioxide, SiO2 and produce molten slag
what is the use of molten slag
to pave roads
what are the chemical equations of the 4 stages of reactants
C + O2 –> CO2
CO2 + C (add more coke) –> 2CO
FeO3 + 3CO (carbon monoxide) –> 2Fe + 3CO2
CaO + SiO2 –> CaSiO3
all metals corrode except…
iron
what are the conditions for rusting to take place
water and oxygen
when iron rusts, it forms…
iron (III) oxide
what are the 2 ways to speed up rusting process
sodium chloride
acidic substances
what are the 3 methods to prevent rusting
painting
sacrificial protection
galvanising with zinc
explain how painting prevents rusting
it coats and provide a protective layer to prevent iron from coming in contact with water and oxygen
one disadvantage of painting to prevent rusting
the paint may be scratched thus rust will take place under the painted surface
explain how sacrificial protection prevent rusting
when 2 metals are together, more reactive metal will corrode in places of less reactive metal
why do we recycle
as metals are in high demand as they are limited resources
what are the advantages of recycling
conserve earth’s finite natural resources
reduces air pollution compared to extraction as it releases toxic gases to the environment
what are the disadvantages of recycling
recycling processes releases harmful gases = air pollution
it is costly (transport, sort, separate and clean) very high costs = not worthwhile
metal + cold water –>
metal hydroxide + hydrogen gas
metal + steam –>
metal oxide + hydrogen gas
why is molten iron formed lower than molten slag in he blast furnace
molten iron is denser than molten slag
thus it is found at the bottom
