Chemistry - Metals
Terms in this set (46)
Which metals in the reactivity series have to be extracted by electrolysis?
Metals higher than carbon
What is a disadvantage of electrolysis?
Which metals in the reactivity series are extracted by reduction?
metals below carbon
What does reduction mean?
process of removing oxygen and gain of electrons
What does oxidation mean?
Process of gaining oxygen and loss of electrons
What is electrolysis?
Process of using electricity to extract a metal and it just means splitting up with electricity
What is a metal ore?
Its a rock but is economically worthwhile extracting and its a metal compound and in many cases the ore is the oxide of a metal, ores are found int he earths crust and more reactive metal is harder to extract from the ore.
describe the properties of transition metals
very strong, high melting points, conductors of electricity, malleable, useful as catalysts, can form more than one type of ion.
what colour is Cu2+
What colour is Fe3+
What colour is Fe2+
what is the transition metal gold used for and why?
Jewellery because its shiny and malleable
what is the transition metal iron used for?
Its used as a catalyst in the Haber process for making ammonia
what is the transition metal platinum used for?
A catalyst used in catalytic converters
what is a catalyst?
a substance that increases the rate of a chemical reaction without being changed for used up
What is a characteristic transition metals have?
They are very colourful
Describe the 5 steps of how aluminium is extracted from its ore by electrolysis
1. Aluminium is extracted from its ore by electrolysis (Al2O3)
2. Al2O3 has a very high melting temperature so its dissolved in molten cryolite to lower the melting point - saves energy.
3. Molten mixture contains free ions so it conducts electricity.
4. The positive AL3+ ions are attracted to the negative electrode where they each pick up 3 electrons and turn them into neutral aluminium atoms - sink to bottom of electrolysis tank.
5. The negative O2- ions are attracted to the positive electrode where they each lose 2 electrons. The neutral Oxygen atoms will then combine to form O2 molecules.
What happens to the positive ions when they move towards the cathode?
They gain electrons (Reduction)
What happens when the ions react with the electrode?
the compound decomposes
What happens to the negative ions when they move towards the anode?
Lose electrons (Oxidised)
What happens when the ions gain or lose electrons?
They form an uncharged element and are discharged from the electrolyte
Whats an electrolyte?
A liquid or solution that conducts electricity by movement of ions
Why cant ionic substances (except molten ionic compounds) by electrolysed?
the ions are in fixed positions and cant move
what are electrodes often made of?
what does the anode attract?
negatively charged non metal ions
What does the cathode attract?
positively charged metal ions
Whats iron ore?
a source of iron
fuel to produce carbon monoxide fro reduction (Almost pure carbon)
removes impurities (Slag formation when limestone breaks down and reacts with sand from rocks)
What are the 5 steps to reducing iron ore to iron?
1. Hot air blasted into furnace which provides Oxygen and makes coke burn faster - raises temp to 1500 degrees.
2. Coke burns in a combustion reaction and produces carbon dioxide.
3. The carbon dioxide then reacts with unburnt coke in a combustion reaction to form carbon monoxide (CO).
4. The carbon monoxide then reduces the iron ore to iron.
5. The iron is molten at this temperature and is very dense, so goes to the bottom of the furnace where its tapped off.
How do you remove sand (Silicon dioxide)?
Limestone removes it
What is limestone decomposed into?
calcium oxide and carbon dioxide
what does the calcium oxide and the sand make?
in a neutrilisation reaction it forms calcium silicate (Slag) which is molten and taped off.
what happens when you put a reactive metal into a solution with a less reactive metal salt?
The metal will replace the less reactive metal in the salt
What happens when you put a less reactive metal into a solution with a more reactive metal salt?
What happens when you have a reactive metal with a less reactive metal oxide?
The more reactive metal will remove it this is called a competition reaction.
What happens in a displacement reaction?
The more reactive metal is oxidised and the less reactive metal is reduced.
Whats an alloy?
a mixture of two are more elements where at least one element is a metal.
what colour is copper sulphate?
What colour is iron sulphate?
Where can metal extraction plants be built?
Near a coast, cant be near urban areas (Noise and pollution), close enough to workers, need a direct supply of electricity near the plant, good transport links.
Why is recycling metals important?
1) Uses less energy than is needed to mine & extract new metals
2) Conserves the finite amount of each metal in the earth
3) Cuts down on the amount of waste getting sent to landfill
malleable and good fro making gates and railings however its very corrosive and rusts easily.
doesn't corrode easily, reacts very quickly with oxygen, useful fr products that come into contact with water, window frames, non toxic so good for food cans, less dense so its light, aeroplanes and bike frames.
Low density, doesn't corrode easily, very hard, light weight, bicycle frames and aeroplanes.
Malleable, ductile, good conductor and heat and electricity, used in the wiring of electrical components, low resistance, used in underground heating systems, attractive colour and lustre - decorations.