Topic 9: Metals Flashcards
List the properties of metals.
- Strong
- Malleable
- Ductile
- Sonorous
- Shiny
- Good conductors of heat and electricity
- High Density
- High melting and boiling points.
List the properties of non-metals.
- Dull
- Low density
- Weak
- Brittle
- Poor electrical conductors
- Poor thermal conductors
- Makes dull sound
- Non-magnetic
How do metals react with acids?
Metal + Acid —-> Salt + Hydrogen
How vigorously they react depends on where they are placed in the reactivity series.
How do metals react with oxygen?
Metal + Oxygen —–> Metal oxide
Some metals are so reactive that they must be kept under oil to prevent reaction from occurring.
They can also be burnt using a Bunsen burner.
Write the word and chemical equation for the reaction between sodium and water.
sodium + water —-> sodium hydroxide + hydrogen
2Na + 2H2O —> 2NaOH + H2
Write the word and chemical equation for the reaction between magnesium and steam.
magnesium + steam —–> magnesium oxide + hydrogen
Mg + H2O —-> MgO + H2
List the uses of aluminium.
manufacture of aircraft –> strong, lightweight
overhead electricity cables –> good conductor of electricity, ductile, resists corrosion
cooking foil and food cartons –> non toxic, resistant to corrosion, can be rolled into thin sheets
drink cans –> light, non-toxic, resistant to corrosion
coating CDs and DVDs –> can be deposited as a thin film, shiny surface reflects laser beam
List the uses of copper.
electrical wiring –> one of the best conductors of electricity, ductile
saucepans and saucepan bases –> malleable, conducts heat well, unreactive, tough
What is an alloy?
A mixture of two elements, on of these being a metal
What are the properties of alloys.
They often have properties that are different to the elements they contain, making them more useful than pure elements alone.
These differences may include hardness, tensile strength, malleability, melting point etc.
What is brass made up of?
Copper and zinc.
State the properties of brass.
It is corrosion-resistant and harder than the elements it is made up of.
What is steel made up of?
Iron and a non-metal carbon.
What is stainless steel made up of?
Iron, carbon, chromium and nickel.
Chromium prevents the steel from rusting
Nickel makes it harder.
State the advantages of using alloys.
They are made up of atoms of different sizes rather than bein uniform.
This means that the layers of atoms cannot slide over each other easily, making the whole alloy much stronger than any of the pure metals.
They tend to have better corrosion resistance
They are more versatile for manipulating into different forms.
State the uses and properties of mild steel.
Properties:
Easily worked
Lost most of the brittleness
Uses:
Car bodies
Large structures
Machinery
State the uses of hard steel.
Cutting tools,
Chisels
Razor blades
State the use of manganese steel.
Drill bits
Spring
State the use of stainless steel
Cutlery,
Kitchen sinks
Surgical instruments
Chemical plant reaction vessels
State the uses of tungsten steel
Edges of high-speed cutting tools
List the reactivity series.
potassium
sodium
calcium
magnesium
aluminium
carbon
zinc
iron
tin
lead
hydrogen
copper
silver
gold
platinum
How do displacement reactions occur?
A more reactive metal displaces a less reactive metal from a compound.
Metals below aluminium in the reactivity series can be reduced by carbon while the oxides of metals above zinc in the reactivity series cannot be reduced by carbon.
These metal oxides are very stable and can be reduced by electrolysis.
How does potassium react with water?
very violent with cold water
catches fire
How does sodium react with water?
violent with cold water
How does calcium react with water?
less violent with cold water
How does magnesium react with water?
very slow with cold water
vigorous with steam
How does zinc react with water?
quite slow with steam
How does iron react with water?
slow with steam
How does copper react with water?
There is no reaction
How do metals react with HCl.
What type of reaction is the displacement of hydrogen?
Redox reaction
Why does aluminium not have any reaction with water/ dilute acid.
Because of its thin oxide which is invisible to the naked eye which protects the metal from these chemicals.
Write the word equation for rusting.
Iron + water + oxygen —-> hydrated iron (III) oxide
How do you prevent rusting?
Paint
Oil/grease
Coat with plastic or another metal
What is galvanisation?
Coating iron or steel with a thin layer of zinc.
This stops oxygen and water from reaching the metal underneath.
It also acts as a sacrificial metal as zinc is more reactive than iron.
How do you extract iron from haematite?
The reaction takes place in a blast furnace.
It is loaded with haematite, coke and limestone.
carbon + oxygen —> carbon dioxide
C + O2 —-> CO2
The limestone begins to decompose
calcium carbonate —–> calcium oxide + carbon dioxide
CaCO3 —–> CaO + CO2
The carbon dioxide produced reacts with more coke higher up in the furnace producing carbon monoxide in an endothermic reaction
carbon dioxide + coke —–> carbon monoxide
CO2 + C —-> 2CO
At 700 degrees Celsius, carbon monoxide reduces the iron oxide ore.
Fe2O3 + 3CO —-> 2Fe + 3CO2
Molten iron trickles to the bottom
Calcium oxide reacts with impurities like silica to form slag.
CaO + SiO2 —-> CaSiO3
How is aluminium extracted?
Bauxite is purified to produce aluminium oxide (alumina).
The extraction is done by electrolysis.
As aluminium oxide has a very high melting point (over 2000 degrees Celsius), it is dissolved in molten cryolite to reduce some of the energy costs involved in extracting aluminium.
At the cathode:
4Al3+ + 12e- —> 4Al
At the anode
6O2- —> 3O2 + 12e- (oxidation)
The oxygen gas bubbles off and reacts with the anode
C + O2 —–> CO2
As the carbon blocks are eaten away, they need to be replaced, which adds to the costs of the process.
Overall reaction
2Al2O3 ——> 4Al + 3O2
