Extracting Metals and Equilibrium Flashcards
(38 cards)
What are the products when a metal reacts with cold water?
Metal hydroxide and hydrogen gas
What are the products when a metal reacts with steam?
Metal oxide and hydrogen gas
What are the products when a metal reacts with a dilute acid?
Salt and hydrogen
If a metal reacts with cold water, what does it suggest above the reactivity of this metal?
The metal is very reactive as only the most reactive can react with cold water
What does a metal reacts with oxygen but not acid or cold water suggest about the reactivity of this metal?
Not very reactive, most metals react with oxygen
What metal won’t react with water, acid or oxygen?
Gold
What is an experiment that uses displacement to compare the reactivity of two metals?
Add a solid metal to a salt solution, if the solid metal is more reactive, it will gradually disappear, displacing the metal that was in the salt solution and if nothing happens, the metal in the salt is more reactive and can’t be displaced
What would you expect to observe when magnesium is added to copper sulfate solution?
The copper sulfate solution is blue, magnesium is more reactive than copper so when magnesium is added the blue solution decolourises and copper coats the surface of the magnesium
Why can a displacement reaction be called a redox reaction?
Occurs when reeducation and oxidation are taking place, in a displacement reaction the more reactive metal atoms lose electrons to form ions and the lies reactive metal ions gain electrons to form the elements
Which metals are most easily oxidised?
Highest in the reactivity series, more likely to react with water and dilute acids to form cations
Where are most metals extracted from?
From ores found in the Earths crust
What is an ore?
A rock which contains metals often chemically combined with other substances
Which metals are found in the earths crust as uncombined elements?
Unreactive metals
What does oxidation mean?
Gain of oxygen
What does reduction mean?
Loss of oxygen
How can metals be extracted from their ores?
Reeducation with carbon: can only be done if the metal is less reactive than carbon and Electrolysis: can be done with all metals, but requires a large amount of energy
How would you extract iron from its ore?
Iron is less reactive than carbon so can be extracted by reduction with carbon and electrolysis could also be used but this would use a lot of unnecessary energy
How can aluminium be extracted from its ore?
Aluminium is more reactive than carbon so electrolysis must be used and when the molten ore undergoes electrolysis the metal forms at the cathode
When aluminium is extracted from aluminium oxide, why is it first dissolved in molten cryolite?
Aluminium oxide has a very high melting point, it’s dissolved in molten cryolite to produce an electrolyte with a lower melting point, reducing energy usage and cost
How can plants be used as an alternative metal extraction method? How does it work?
Phytoextraction: plants are grown in areas with metals in the soil, the plants take up metals through their roots and concentrate them in their shoots and leaves, these plants are burned and the metals are removed from the ash
How can bacteria be used as an alternative metal extraction method?
Bacteria extraction: some bacteria absorb metal compounds, these bacteria produce solution called leachates containing the metals and scrap iron can be used to remove the metal from the leachate
What are limitations of biological methods of extraction?
Only suitable for low grade ores with smaller quantities of metals, slow processes and require displacement or electrolysis for the final step
How is a metals relative resistance to oxidation related to its position in the reactivity series?
Metals lower in the reactivity series are less reactive, this means they are less likely to form their cations so are more resistant to oxidation
What are the advantages of recycling metals?
Economically beneficial, less wage produced so less landfill, less energy is required, more sustainable and recycling process provides employment