Chemistry · Oct / Nov 2016 · Paper 22 · Question A5
5070
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The question as text
A5 Nickel carbonyl, Ni(CO)4, reacts with hydrogen iodide. Ni(CO)4(l) + 2HI(g) NiI2(s) + H2(g) + 4CO(g)
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A5(a)[2]
34.5% (2)
If two marks not scored, 171 (for molar mass of nickel carbonyl) scores 1 mark 2
A5(b)[3]
mol nickel carbonyl = 1.71 171 OR 0.01 (mol) (1)
mol gases = (0.01) × 5/idea of multiplying mol × 5 (1)
volume of gases = 1.2 dm3/1200 cm3 (units must be correct) (1)
3
A5(c)[2]
low melting point/low boiling point (1)
does not conduct electricity (1)
2
A5(d)[2]
isotopes (1)
cobalt has greater proportion of heavier isotopes than nickel/nickel has lower proportion of lighter isotopes than nickel (1)
2
A5(e)[1]
acid that is completely ionised/acid that is completely dissociated/acid that releases all ionisable hydrogen (1)
1 Total: 10
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