Metals and Metal Extraction Flashcards
Why do metals have high boiling points?
because a metallic lattice is held together by strong forces of electrostatic attraction which require a lot of energy to overcome
Why are metals good electric conductors?
they have delocalised electrons which are free to move
Why are metals good thermal conductors?
they have delocalised electrons which move around the metal and transfer thermal energy to the ions
Why are metals malleable?
the ions are arranged in regular layers which can slide over each other and bend instead of break
Why are metals ductile?
layers slide over each other when pulled apart, forming a thin wire
What happens when a metal reacts with dilute acids?
they produce a salt and hydrogen
Write a general word equation for the reaction between metals and dilute acids.
metal + dilute acid -> salt + hydrogen
What happens when a metal reacts with water?
they form a metal hydroxide and hydrogen gas
Write a general word equation for the reaction between metals and water.
metal + water -> metal hydroxide + hydrogen gas
What happens when a metal reacts with oxygen?
they form metal oxides
Write a general word equation for the reaction between metals and oxygen.
metal + oxygen -> metal oxide
Name 3 uses of aluminium.
- manufacture of aircraft
- manufacture of overhead electrical cables
- food containers
What is one use of copper?
electrical wiring
Why is aluminium suitable for the manufacture of aircraft?
it has a low density
Why is aluminium suitable for the manufacture of overhead electrical cables?
it has a low density and is a good electrical conductor
Why is aluminium suitable for food containers?
it is resistant to corrosion
Why is copper suitable for electrical wiring?
it is a good electrical conductor and ductile
What is the order of the reactivity series, from most to least reactive?
potassium
sodium
calcium
magnesium
aluminium
carbon
zinc
iron
lead
hydrogen
copper
silver
gold
What are the three most reactive metals?
potassium, sodium and calcium
Describe the reaction between sodium and cold water.
floats
moves quickly
heat from reaction melts sodium
Describe the reaction between potassium and cold water.
floats
melts
catches fire- burns with a lilac coloured flame
Describe the reaction between calcium and cold water.
reacts quickly
water turns milky white
Describe the reaction between magnesium and steam.
reacts readily
forms magnesium oxide and hydrogen
Describe the reaction between zinc and dilute hydrochloric acid.
bubbles formed slowly
Which four metals react with water/steam?
potassium
sodium
calcium
magnesium
Describe the reaction between magnesium and dilute hydrochloric acid.
strong bubbles formed quickly
Describe the reaction between iron and dilute hydrochloric acid.
very slow reaction
must be powdered iron
Describe the reaction between copper and dilute hydrochloric acid.
none
Describe the reaction between silver and dilute hydrochloric acid.
none
Describe the reaction between gold and dilute hydrochloric acid.
none
In a displacement reaction, which metal will lose electrons?
the more reactive metal
In a displacement reaction, which metal will gain electrons?
the less reactive metal
Define oxidation
loss of electrons
increased oxidation number
Define reduction
gain of electrons
decrease in oxidation number
The more reactive a metal is, the more _____ it will lose its valence electrons.
easily
State which metals have a higher tendency to form positive ions in a displacement reaction.
more reactive metals
A ______ metal will displace a _______ metal.
more reactive
less reactive
Is aluminium reactive? Why might we think otherwise?
aluminium IS reactive
oxide layer: surface atoms of aluminium react with oxygen in air to form an oxide layer, protecting the inner metal from corroding
Define ‘metallic bonding’.
the electrostatic attraction between the positive ions in a giant metallic structure and the surrounding ‘sea’ of delocalised electrons
Why are metals good electrical conductors?
there are many delocalised electrons that can flow
Why are metals malleable?
because they are arranged in layers that slide over each other
Define ‘alloy’.
a mixture of a metal with other elements
What elements make up brass?
copper and zinc
What elements make up stainless steel?
iron, and other elements such as chromium, nickel and carbon
Why do people form alloys?
they can be harder, stronger and more useful than pure metals
Why are alloys stronger/harder than pure metals?
different sized atoms in alloys prevent layers from sliding over each other
What is a use of stainless steel?
cutlery
Why is stainless steel used for cutlery?
hard
resistant to rusting
What occurs in a redox reaction?
oxidation and reduction simultaneously
loss and gain of electrons
What is the oxidation number of elements in their uncombined state? What are examples of this?
0
O2, Mg
What is the sum of the oxidation numbers in a compound?
0
What is an oxidising agent?
a substance that oxidises another substance, being reduced in the process
What is a reducing agent?
a substance that reduces another substance, being oxidised in the process
What are the conditions required for rusting?
oxygen and water
Word equation for rusting
iron + water + oxygen → hydrated iron(III) oxide
State 4 common barrier methods.
painting
greasing
coating with plastic
galvanising
How do barrier methods prevent rusting?
they exclude oxygen and water so it does not get to the metal
What substance increases the rate of rusting?
salt
In which substances does rusting occur?
steel and iron
Give an example of sacrificial protection.
galvanising
What are barrier methods?
methods that prevent iron from getting in contact with oxygen and water, preventing rusting
Why is it important to prevent rusting?
rusting weakens important structures such as ships, which is dangerous
What is sacrificial protection?
covering iron/steel with a more reactive metal which slowly sacrifices itself for the iron/steel
What is galvanising?
a specific form of sacrificial protection with zinc
How can we extract more reactive metals from their ores?
electrolysis
Which metals require electrolysis to be extracted from their ore?
metals above carbon in the reactivity series
potassium, sodium, calcium, magnesium, aluminium
How can we extract somewhat reactive metals from their ores?
reduction, using carbon/coke/charcoal
Which metals require reduction to be extracted from their ore?
zinc
iron
lead
Which metals do not need to be extracted? Why?
copper, silver, gold, platinum
unreactive and occur native
Describe the extraction of iron from hematite in the blast furnace.
- coke is burned, providing heat and producing carbon dioxide
- coke reacts with carbon dioxide to form carbon monoxide/carbon dioxide is reduced to carbon monoxide
- iron (III) oxide is reduced by carbon monoxide
- calcium carbonate is thermally decomposed to form calcium oxide and carbon dioxide
- calcium oxide and silicon dioxide react to form slag (CaSiO3)
How is aluminium extracted?
electrolysis
What is the main ore of aluminium?
bauxite
Write the balanced symbol equation for the reduction of iron oxide in the blast furnace.
Fe2O3 + 3CO → 2Fe + 3CO2
Write the balanced symbol equation for the formation of slag in the blast furnace.
CaO + SiO2 → CaSiO3
Write the balanced symbol equation for the thermal decomposition of limestone in the blast furnace.
CaCO3 → CaO + CO2
State the symbol equations for the extraction of iron from hematite
(a) C + O2 → CO2
(b) C + CO2 → 2CO
(c) Fe2O3 + 3CO → 2Fe + 3CO2
(d) CaCO3 → CaO + CO2
(e) CaO + SiO2 → CaSiO3
