2.3 Flashcards
(14 cards)
what is an alloy
a mixture of molten metals whos properties change due to their changing composition
colours of iron (II) , iron (III) and copper (II) ions
pale green, brown, blue
how is electrolysis used to purify copper (4 marks)
the anode is a big lump of impulse copper and the cathode is a thin piece of pure copper. during electrolysis the impure copper is oxidised and dissolves into the electrolyte to form copper ions which move got the cathode where they’re reduced and coat it with a pure layer of copper
why can’t ionic solids be electrolysed and which type of ionic compounds can and why
as the ions are in fixed positions and can’t move
molten as they can move freely and conduct electricity
are metals positive or negative
positive
are non metals positive or negative
negative
during the electrolysis of water, what ions are present, do they go to the cathode or anode and what gases are formed
hydrogen ions go to the cathode and form hydrogen gas and hydroxide ions go to the anode and form oxygen gas
in aqueous solutions, what ions are present
ions from the ionic compound, hydrogen ions and hydroxide ions (from the water)
what are the steps to extract iron?
Hot air is blasted into the furnace which provides oxygen and makes the coke burn faster and raises the temperature
The Coke burns in a combustion reaction to produce carbon dioxide
Carbon dioxide reacts with embers Coke to form carbon monoxide
Carbon monoxide reduces the iron ore iron
How is silicon dioxide removed by limestone?
limestone is decomposed by the heat into calcium oxide and carbon dioxide
Calcium oxide reacts with the silicon dioxide in the neutralisation reaction to form calcium silicate or slag which is molten and can be tapped off
Why is aluminium oxide dissolved in molten cryolite?
as aluminium oxide has a very high melting point whereas cryolite needs a lower temperature therefore when aluminium oxide is dissolved in it it reduces the energy needed for extraction
in the electrolysis of aqueous solutions at the cathode, if ions and metal ions are present. What will be produced?
if the metal ions form a metal that is more reactive than hydrogen than hydrogen gas will be produced if it’s less reactive then a solid layer of pure metal will be produced
at the anode if OH- and halide ions are present what will be formed and if they aren’t then what will
cl, br, I
oxygen
