C4 Extracting metals and Equilibria Flashcards
Where are metals found and in what form?
- extracted from ores
- in earth crust
- unreactive metals are found as combined elements
metal + acid –> ??
metal salt + hydrogen
metal + water –> ??
metal hydroxide + hydrogen
How can we deduce reactivity of a metal when reacted with water?
metal + H2O –> metalOH + H
- hyrogen gas produced in form of bubble
- the more bubbles the more reactive
What is the reduction and oxidisation? (with oxygen)
reduction
-loss of oxygen
oxidisation
-gain of oxygen
How does the reactivity series affect the relative resistance to oxidisation?
a less reactive metal will not displace a more reactive metal from a metal salt so relatively oxidation will or will not occur
Which metals are more reactive than carbon?
- potassium
- sodium
- calcium
- magnesium
- aluminium
Which metals are more reactive than hydrogen?
- potassium
- sodium
- calcium
- magnesium
- aluminium
- zinc
- iron
- lead
Which metals are less reactive than carbon?
- zinc
- iron
- lead
- copper
- silver
- gold
- platinum
Which metals are less reactive than hydrogen?
- copper
- silver
- gold
- platinum
Which metals are unreactive with water?
- lead
- copper
- silver
- gold
- platinum
What are displacement reactions? (electrons)
- more reactive metal replace less reactive metal from a metal salt
- redox reaction
- gain and loss of electrons (oilrig)
What are the two most common methods of metal extraction?
- burning metal ores with carbon
- electrolysis
Why does a metals position in the reactivity series determine what extraction process to use?
-burning with carbon
–displacement reaction
—if metal is more reactive than carbon displacement will not occur so no metals are extracted
electrolysis used for metals more reactive than carbon and not others since it is expensive
Which metals can be extracted from metal ores by being burnt with carbon?
zinc iron tin lead copper silver gold platinum
Which metals must be extracted from metal ores by electrolysis?
potassium sodium calcium magnesium aluminium
How useful are biological methods of metal extraction? 2 examples
phytoextraction
bioleaching
advantages:
- reduce need for mining
- conserves high grade ores
- allows use of low grade ores
- can be used to decontaminate ground
- reduces rock waste from mining
- preserves natural habitats
(b) -doesnt require high temp
disadvantages:
- very slow process
(p) - requires high temperatures
(p) - CO2 produced when plants are burned which is a green house gas
(b) - produces toxic substances eg sulfuric acid which damage environment
What are the environmental benefits of recycling? (metals)
-less mines –reduces deforestation –reduces noise and dust pollution -reduced waste sent to landfill –saves valuable space -conservation of raw material -conservation of fossil fuels -less energy required to recycle than to mine -reduces greenhouse gas emissions from consumption of fossil fuels to mine
What are the economic benefits of recycling?
-recycling requires less energy than mining
–reduced energy cost
-recycled metals and materials are cheaper to buy than raw materials
-recycling is an industry
–jobs
–economic growth
What factors do you need to consider when evaluating each stage of the life cycle assessment of a product?
- energy required
- amount of water needed
- amount if resources used
- waste produced (in all forms)
- waste disposal
- impact on environment of all above points
