topic 4 - metals and reactivity Flashcards
what does the reactivity series show
how easily metals are oxidised
what two non-metals are included in the reactvitiy series
carbon and hydrogen
metals at the top of the reactivity series (description)
are most reactive
lose electrons easily to form cations
oxidised easily
metals at the bottom of the reactivity series (describe)
less reactive
don’t form cations as easily
more resistant to oxidation
what is the reactivity series (LIST)
potassium sodium calcium magnesium aluminium CARBON zinc iron HYDROGEN copper silver gold
what metals are more reactive than carbon
potassium sodium calcium magnesium aluminium
what metals are more reactive than hydrogen but less reactive than carbon
zinc
iron
what metals are less reactive than hydrogen
copper
silver
gold
to determine a metal’s position in the reactivity series
react it with water and dilute acids
reacting metals with acids ( what you do, the three indications of more reactive metals )
place small pieces of a variety of metals in dilute hydrochloric acid
the more reactive the metal, the faster it will react with the metal
the faster bubbles appear, the more reactive the metal
the louder the pop, the more hydrogen produced so the more reactive
hydrogen test
using a burning splint, if there is a squeaky pop heard then hydrogen is present
metal + water ->
metal + water -> metal hydroxide + hydrogen
less reactive metals don’t react with what
water
but will react with steam
less reactive metal + steam ->
less reactive metal + steam -> metal oxide + hydrogen
how to react a less reactive metal with steam
place mineral wool soaked in water into a boiling tube with metal
heat it
redox reaction
a reaction where reduction and oxidation occur simultaneously
a displacement reaction is a redox reaction
displacement reaction
the more reactive element takes the place of a less reactive element in a compound
a displacement reaction is a redox reaction
in metal displacement what happens in terms of electrons
the more reactive metal loses electrons (oxidised)
the less reactive metal gains electrons (reduced)
what can displacement reactions be used for
working out the position of a metal in the reactivity series
metal ore
a rock which contains enough metal to make it economically worthwhile to extract the metal within it
ore is often the oxide of the metal
where are ores found
the Earth’s crust
ores and unreactive metals (notes)
unreactive metals are present in the Earth’s crust as uncombined elements
these include gold and platinum
once mined out of the ground, they tend to need to be refined before use
extraction using carbon
the metal is extracted from its ore chemically, using reduction
ore is reduced, removing oxygen from it
why does extraction using carbon work
the carbon is more reactive than the metal so takes away the oxygen
extraction of iron oxide
extraction using carbon
iron oxide reduced using a blast furnace
2Fe2O3 + 3C -> 4Fe + 3CO2
when should electrolysis be used for extraction
when metals are higher than carbon in the reactivity series
how do you extract a metal using electrolysis
once a metal ore is melted, an electric current can be passed through it
the metal gathers/ is discharged at the cathode
the non-metal gathers/ is discharged at the anode
compare methods of extraction in terms of cost
electrolysis is more expensive than reduction with carbon because large amounts of electricity are needed
biological methods of extraction (definition)
methods of extraction using living organisms
2 examples of biological methods of extraction
bioleaching
phytoextraction
bioleaching
bacterial method of separating metals from their ores
bioleaching process
bacteria take energy from bonds between atoms in the ore, which separates the metal from the ore
leachate (solution produced by bioleaching) contains metal ions which can be extracted using displacement with a more reactive metal or electrolysis
phytoextraction process
growing plants in a soil containing metal compounds
metals build up in the leaves because the plant doesn’t use them
the plants are then harvested, dried and burned in a furnace
the ash produced can then have metal removed using electrolysis or displacement
3 general advantages of recycling
conservation of resources and energy
economic benefits
protects environment
conservation of resources and energy
extracting raw materials takes lots of energy which is coming from burnt fossil fuels that are non-renewable , running out and contribute to acid rain/climate change
recycling materials saves energy
metals are also non-renewable so recycling is important for conserving them especially if they are rare
economic benefits of recycling
extracting materials uses lots of energy which is expensibe
beneficial to the economy to recycle expensive materials
so recycling is a huge industry creating lost of jobs (jobs are created at every stage of the process)
how does recycling protect the environment
recycling reduces the amount of rubbish in landfill which takes up space and pollutes surroundings
extracting metals impacts the environment as mining damages environments and habitats
life cycle assessment
looks at each stage of a product’s life
works out the potential environmental impact at each stage
what are the 4 stages of the life cycle assessment
choice of material
manufacture
product use
disposal
considerations with choice of material
metals need to be mined from their ores, needing energy and causing pollution
raw materials often come from crude oil, whose refinery needs energy
considerations with manufacture
making products uses lots of energy and other resources
- waste product disposal should be considered
- water shouldn’t be put back polluted
- recycling can reduce pollution
considerations with product use
how much damage using the product may cause the environment
considerations with disposal
products may be disposed in landfill, taking up space and polluting land and water
if burnt, it will cause air pollution
