SC11 Flashcards
(28 cards)
What are aome typical properties of a metal?
-High melting/boiling point
-Conductor of electricity and heat
-malleable
-ductile(ability to be formed into wires)
-solid at room temperature
-most r shiny
what observations can be made when sodium reacts with water?
-fizzing
-glame
-sodium metal cuve melts into a sphere
-sodium floats and moves around on water’s surface
-sodium becomes smaller and disappears
which is higher in the reactivity series? Sodium or potassium, why?
Potassium reacts more violently with water than sodium so it is more reactive than sodium.
Hence potassium is placed above the sodium in reactivity series
Observation in reaction of water and potassium?
-reacts more quickly compared to sodium
-with a lilac flame due to K+ ions
- reduces in size and quickly disappears
-fizzes
-floats on water
-Flame is due to burnign of H2, H2 is flammeavle
Why is gold silver and platinum placed at the bottom of the reactivity series?
higjly reactive
Ca can react with cold water
Mg can react very slowly with water but quickly in steam
What does this tell of the reactivity series of Ca and Mg placement
Means that calcium is more reactive than Mg and is placed above Mg in reactivity series
Say reactivity seties from most reactive to least reactive
-Potassium
-Sodium
-Calcium
-Magnesium
-Aluminium
(Metals above must be extracted through electrolysis)
Carbon
-Zinc
-Iron
-Tin
-Lead
Hydrogen
-Copper
-Silver
(from silver to zinc, must be extracted vis heating w carbon)
-Gold
-Platinum
What is a displacement reaction?
when a more reactive metal displaces a less reactive metal to form a solution of its compound
What is a redo reaction?
When both oxidation and reduction occur simulatneously
What is an ore?
a rock that contains enough of a compound to extract a metal for profit
Name what compound and metal extracted to get the ore of malachite, haematite, bauxite
Malachite is from the compound Copper(II) Carbonate, extracted from copper
Haematite is from teh compound Iron(III) Oxide is extracted from iron
Bauxite is from the compound Aluminium Oxide extracted from aluminium
Describe the extraction of iron to get ore Haematite in INCREDIBLE detail
Ore: Haematite
The compound present is iron(III) oxide
Iron is extracted from iron(III) oxide by heating it with carbon, this works because carbon is above iton in the reactivity series. So carbon is more reactive than iron and can displace iron from iron(III) oxide
iron(III) oxide + carbon = iron + carbon dioxide
2Fe2O3 + 3C > 4Fe + 3CO2
This is a redox reaction as both oxidation and reduction occur simultaneously
Fe2O3 is reduced because it loses oxygen
Carbon is oxidised because it gains oxygen
Carbon is a reducing agent because it causes the iton(III) oxide to lose oxygen and get reduced
Describe the extraction of copper in INCREDIBLE detail
Ore Malachite
Compound present is copper(II) carbonate
Copper(II) carbonate is heated, it decomposes into copper(II) oxide and carbon dioxide
CuCO3 > CuO(s) + CO2(g)
Copper is extracted from copper(II) oxide by heating with carbon
This method works because carbon is more reactive than copper and can displace copper from copper(II) oxide
2CuO(s) + C(s) > 2Cu(s) + CO2(g)
Copper(II) oxide is reduced because it loses oxygen
Carbon is oxidised because it gets oxygen
Extraction of Aluminium in INCREDIBLE GREAT detail
Ore: Bauxite
Compound found is Aluminium Ocide
Aluminium is extracted by electrolysis because aluminium is more reactive than carbon
It cannot be extracted by heating with carbon because carbon is less reactive than alumijium and ctherefore cannot displace aluminium from aluminium oxide
Aluminium oxide is made up of Al3+ and O2- ions, when the power is switched on Al3* ions get attached to the cathode, and O2- are attracted to the anode
at the cathode AL3+ ions gain electrons, and get reduced to AL atoms(l)
Al3+ + 3e- > Al(l)
Observation
-molten grey liquid settles at the bottom
at the anode oxide ions, lose electrons and get oxidized to oxygen atoms to oxygen atoms, bond covalently to form O2 molecules
2O2- + O2 + 4e-
Observation
-bubbles
overall electrolysis equation
2Al2O3(l) > 4Al(l) + 3O2(g)
describe bioleaching, its pros and cons
referring to copper
Uses bacteria grown on a low grade ore. the bacteria produce a solution containing copper ions, called leachate. copper is extracted from the leachate by displacement using scrap iron, then purified by electrolysis.
pros
- does not require high temp
cons
-toxic substances and sulfuric acid can be produced by the process and damage of the environment
describe phytoextraction in detail, pros and cons included
involves growing plants that absorb metal compounds, the plants are burnt to form as which metals are extracted from
pros
-can extract metals from contaminated soils
cons
-more expensive than mining some ores
-growing plants are dependent on weather conditions
what is corrosion?
- happens when a metal reacts with oxygen forming metal oxide, which makes the metal weaker
expand on corrosion
less reCtive metals such as silver oxides slowly, gold and other very unreactive metals may not react with oxygen at all
metals may form a thin layer of tarnish when they oxidise, this layer stops oxygen reaching the metal preventing further oxidation
what is rusting?
rusting is the specific name given to the corrosion of iron, it is a chemical reaction between oxygen iron and water whi h froms Hydrated iron(II) oxide
Conditions of rusting?
-oxygen and water must both be present
testing for conditions of rusting
4 tubes containing iron nail
tube 1: contains calcium chloride which absorbs the moisture from the air. so water is not present and nail will nto rust
tube 2: contains distilled water, so then air is present so iron nsil rusts
tube3: contaijs boiled water, with a layer of oil preventing oxygen from entering the tube so iron nail will not rust
tube4: contains water dissolved with ions so oxygen is present so iron nail will rust
equation for iron reacting w oxygen and water
4Fe + 3O2 + xH2O > 2Fe2O3cH2O
a redox reaction as
iron atoms lose electrons forming Fe3* ions
Fe > Fe3+ + 3e-
Oxygen molecules gain electrons to form O2 this is reduction
O2 + 4e- > 2O2-
Ways in which corrosion can be prevented?
- Paint over the piece
- Galvinization
- Sacrificial Protection
What is galvinization?
-Coating of zinc on an iron object
-coat of zinc prevents oxygen and water from reachinng the iron so the iron objects do not rust,
-zinc is more reactive than iron so sven if the layer of zinc is scratched xinc gets oxidised in preferance to iton hence prevents iron from rusting
