sc11, obtaining and using metals (paper 1) Flashcards
state the order of metals from most reactive to least reactive
- potassium
- sodium
- calcium
- magnesium
- aluminium
- carbon
- zinc
- iron
- tin
- lead
- hydrogen
- copper
- silver
- gold
mnemonic for metal reactivity
please stop calling me a careless zebra instead try learning how copper saves gold
what does a metal and water produce
metal hydroxide + hydrogen
what does a metal and acid produce
salt + hydrogen
is the rate of reaction greater in warm acids or cold acids
warm acids
true or false: the more reactive the metal, the easier it forms cations
true
true or false: the more reactive the metal, the harder it forms cations
false
what is an ore
a rock that contains enough of a compounds to extract a metal for profit
how can we extract metals less reactive than carbon
through reduction by heating it with carbon
why don’t we often reduce copper oxide to copper with hydrogen
because it’s hazardous
how can we reduce iron oxide
using carbon in a blast surface
give the word equation for reducing iron oxide using carbon in a blast surface
iron oxide + carbon –> (molten) iron + carbon monoxide
give the symbol equation for reducing iron oxide using carbon in a blast surface
Fe2O3 (s) + 3C (s) –> 2Fe (l) + 3CO (g)
how else can we reduce iron oxide except using carbon in a blast surface
reduce by carbon monoxide
give the word equation for reducing iron oxide using carbon monoxide
iron oxide + carbon monoxide –> (molten) iron + carbon dioxide
give the symbol equation for reducing iron oxide using carbon monoxide
Fe2O3 (s) + 3CO (g) –> 2Fe (l) + 3CO2 (g)
for metals more reactive than carbon, how do we extract it
electrolysis
true or false: a high grade ore means a high proportion of metal/metal compounds
true
true or false: a low grade ore means a low proportion of metal/metal compounds
true
true or false: a high grade ore means a low proportion of metal/metal compounds
false
true or false: a low grade ore means a high proportion of metal/metal compounds
false
general properties of low grade ores
- more common
- less profitable
- use more energy
- produce more waste when used
what are the two biological methods of extracting metal from ores
phytoextraction and bioleaching
steps of phytoextraction
- grow plants that absorb metal compounds in roots
- plants concentrate metal compounds in its shoots and leaves
- plant is burned to form ash
- from which the metal is extracted from
steps of bioleaching
- using bacteria grown on a low grade ore
- that produces a solution containing metal ions, called leachate
- metal is extracted from the leachate using scrap iron
advantages of bioleaching
cheaper
disadvantages of bioleaching
- slow
- produces toxic substances (e.g sulfuric acid)
advantages of phytoextraction
doesn’t cause mining problems
disadvantages of phytoextraction
slow
why are we using biological methods for extracting metals
- we are running out of high grade copper ores
- electrolysis is too expensive for low grade ores
what is corrosion
- when a metal reacts with surrounding substnces such as air and water
- making the metal weaker over time
- also a result from oxidation
true or false: more reactive metals easily corrode
true
true or false: less reactive metals easily corrode
false
what is the corrosion of iron and steel called
rusting
what does rusting require
oxygen and water
why doesn’t aluminium corrode
their surfaces have a protective oxide layer in tarnish which prevents further reactions
define tarnish
not shiny
why are unreactive metals found in their native state
they can’t combine or react with other metals
true or false: carbon cannot reduce metals more reactive than itself
true
true or false: carbon can reduce metals more reactive than itself
false
disadvantages of extracting metals from their ores
- uses up limites resources
- uses a lot of energy
- damages the environment (waste rock and carbon dioxide)
advantages of recycling metals
- metal ores last longer
- less energy is needed
- less land
- less noise and dust
- fewer quarries and mines
- saved energy
disadvantages of recycling metals
- used metal itoms must be collected and transported to the recycling centre
- different metals must be removed from used items and sorted
- recycling saved different amounts of energy, depending on the metal involved
what does LCA stand for
life-cycle assessment
steps of LCA
- obtaining raw materials
- manufacturing the product
- using the product
- disposing of the producr
what data does LCA NEED
- use of energy
- release of waste materials
- transport/storage in most/all stages
what data does LCA LIKELY to need
- whether the raw materials are renewable or non-renewable
- if the product can be recycled or re-used
- how the product is disposed of
reasons for obtaining LCA’s
- identifying alternative materials with less impact
- identify a stage which could be improved
