Metals Flashcards
What are the downsides to mining for metal?
Pollution
Landscape scars
Habitat destruction
What are the properties of copper?
Unreactive - So no reaction when combined with water which gives it a longer useful lifespan
Malleable
Conducts electricity and heat well
What is the most reactive metal?
Potassium
What is a native metal?
One that is found pure in its metallic form in nature e.g. gold & silver
What will a more reactive metal displace a less reactive one from?
A solution of one of its salts (compound)
Is a displacement reaction endothermic or exothermic?
Exothermic
What is a competition reaction?
When a more reactive metal removes oxygen from the oxide of a less reactive metal
Where are transition metals found in the periodic table?
The centre
What properties do transition metals have?
High mpt & bpt Malleable High density Good conductors of heat & electricity Less reactive than alkali metals
What are the colours of compounds/solutions of Fe2+, Fe3+ and Cu2+ ions?
Fe2+ = Pale green Fe3+ = Brown Cu2+ = Blue
How can we test for the presence of transition metal ions?
By using a solution of sodium hydroxide
What precipitates do Copper, Iron(II) and Iron (III) reactions with sodium hydroxide solution create?
Cu2+ = Blue precipitate [Cu(OH)2)(s)] Fe2+ = Green precipitate [Fe(OH)2(s)] Fe3+ = Orange/Brown precipitate [Fe(OH)3(s)]
What is an alloy?
A combination of 2+ elements, where at least 1 is a metal. It is a mixture.
Why is the alloy steel more useful than iron?
It is harder and stronger
How can different types of steel be made?
By changing its composition e.g. varying carbon content (steel is made from iron and carbon)
Mild steel (little carbon) is malleable and easily shaped High carbon steel is harder and more brittle
What are the raw materials that go inside of a blast furnace and what functions do they serve?
Iron ore - Source of iron
Coke - Acts as a fuel (produces carbon monoxide for the reaction)
Limestone - Removes sandy impurities
Hot air - Provides oxygen so that coke can burn
What happens inside a blast furnace?
Industrial reduction of iron oxide
What are the 4 chemical processes that take place in the blast furnace?
1) Combustion
Coke burns in hot air to produce carbon monoxide
2)Reduction of iron (II) oxide
Iron oxide is reduced into iron
3) Decomposition of calcium carbonate
Limestone thermally decomposes to form calcium oxide
4) Neutralisation of silicon dioxide
Basic CaO reacts with sandy impurities to produce slag (Calcium silicate)
(CaO is a base and SiO2 is acidic so they neutralise each other)
How do molter slag and molten iron remain separate at the bottom of the blast furnace?
Molten slag is less dense than the iron and so stays on top
What does it mean when it is said that the process inside of a blast furnace is continuous? Why does it need to be this way?
The furnace is kept hot and new materials are constantly added. This is because getting the furnace up to the temperature required takes a lot of time and energy.
What is electrolysis?
Splitting a compound using electricity
What is electrolysis used for?
It is used industrially in the production of reactive metals such as aluminium from their ores
What are the positive and negative electrodes called?
Pos = Anode Neg = Cathode
What is an electrode typically made of?
Metal or graphite because they can conduct electricity
What is the name for the compound that is being split in electrolysis?
The electrolyte
What occurs at the cathode during electrolysis?
Positive ions are attracted and they gain electrons. This is called reduction
What occurs at the anode during electrolysis?
Negative ions are attracted and they lose electrons. This is called oxidisation
Why is cryolite added to the electrolyte in electrolysis?
To reduce the melting temperature. This saves a lot of electrical energy and money
Where would you geographically put a metal plant?
On the coast - Ore needs to be imported
Near a power station - Needs a source of cheap electricity because so much is used
Away from major population centres
Near good transport system
Not to far from civilisation - Need staff
Why does the electrolyte in electrolysis need to be molten?
So that the ions can move
What uses does aluminium have?
Aeroplanes - Low dendity
Foil - Protective oxide layer prevents is from reacting with food
Overhead power lines - Good conductor of electricity + low density prevents wires from sagging
What uses does copper have?
Wires - Ductile so can be stretched into wire shape + good conductor
Plumbing - Does not react with water (doesn’t corrode)
Cooking - Good conductor + doesn’t react with water
What uses does titanium have?
Artificial hip joints - Low density
Fighter aircraft - Hard + strong
Pipes in nuclear power stations - Thin protective layer of oxides prevents corrosion + very high mpt
What is collected at each electrode during the electrolysis of water?
Hydrogen gas at the cathode and oxygen gas at the anode
Will more hydrogen or oxygen be produced in the electrolysis of water?
Twice as much hydrogen is formed as oxygen as for every oxygen atom in a molecule in water there are two hydrogen atoms
What is produced at the electrodes in the electrolysis of aqueous solutions?
Cathode - Metals lower than hydrogen in the reactivity series Anode - The metal e.g. Copper (II) chloride Cath - Cu An - Cl2
When the dissolved salt includes ions from metals that are higher than hydrogen in the reactivity series, hydrogen gas is formed rather than the metal at the cathode
What could you expect to see at each electrode after electrolysis of copper oxide?
Cathode - A coating of copper
Anode - Oxygen gas bubbles
What is a disadvantage of using electrolysis to extract reactive metals?
Very expensive
In the electrolysis of aqueous solutions, what products can form at the anode?
1) Oxygen gas
2) A halogen (fluorine, chlorine, bromine, iodine, or astatine)
When no halogens are present oxygen will be produced by the OH- ions present in the solution
In the electrolysis of aqueous solutions, what products can form at the cathode?
1) Hydrogen gas
2) A metal
The metal will only be produced if it is lower in the reactivity series than hydrogen (e.g. copper)
What characterises a more reactive met
A metal that forms a positive ion more easily
Why is carbon used to extract metals from their oxides?
Good conductor + Cheap
What is produced when reactive metals react with cold water?
Metal hydroxide + Hydrogen gas
What are the 2 types of metal in the periodic table?
Transition metals
Alkali metals
Why effect does its ionic structure have on an alloy?
The ions are of different sizes which makes it more difficult for layers to slide over each other (makes alloy stronger)
