Chemistry · Oct / Nov 2016 · Paper 22 · Question B10
5070
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The question as text
B10 A student prepared some crystals of hydrated copper(II) sulfate by reacting excess insoluble copper(II) oxide with dilute sulfuric acid. CuO + H2SO4 + 4H2O CuSO4.5H2O
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B10(a)[3]
filter (off excess copper oxide) (1)
evaporate (filtrate) to crystallisation point/leave in warm place to crystallise/heat (solution) until saturated (1)
dry with filter paper/dry in a drying oven (1)
3
B10(b)[3]
mol sulfuric acid = 15 2.0 1000 × OR 0.03 (1)
molar mass of hydrated copper sulfate = 250 (1)
mass of hydrated copper sulfate = 7.5 g (1)
3
B10(c)[2]
(light) blue precipitate (1)
dark blue solution (in excess) (1)
2
B10(d)[2]
anode: oxygen/O2 (1)
cathode: copper/Cu (1)
2 Total: 10
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