Chemistry · Oct / Nov 2021 · Paper 41 · Question 2
0620
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The question as text
This question is about copper and its compounds.f 63 6
Read automatically from the paper; the printed page above is exact.
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2(a)(i)[1]
isotopes
2(a)(ii)[3]
1 mark for each correct row
63Cu
65Cu2+
p
29
29
n
34
36
e
29
27
2(a)(iii)[2]
M1 = (70 × 63) + (30 × 65) or [ ( 4410) + (1950) ] or 6360 (1)
M2 = M1 / 100 = 63.6 (1)
OR
M1= (0.7(0) × 63) + (0.3(0) × 65) or [ (44.1(0) ) + (19.5(0)) ] (1)
M2 = 63.6 (1)
2(b)(i)[2]
M1 white (1)
M2 to (light) blue (1)
2(b)(ii)[1]
5H2O
2(b)(iii)[1]
heating
2(b)(iv)[2]
M1 boiling point (1)
M2 is 100 °C
OR
M1 freezing point (1)
M2 is 0 °C (1)
2(c)(i)[1]
blue precipitate
2(c)(ii)[3]
Alternative suggestion:
M1 Cu(OH)2 (as only product) (1)
M2 Cu2+ and 2OH– (as reactants) (1)
M3 state symbols (1)
2(d)[4]
M1 188
M2 4.7 / 188 = 0.025(0)
M3 0.025(0) × 2 = 0.05(0)
M4 0.05(0) × 24.0 = 1.2
2(e)[2]
2NaNO3 → 2NaNO2 + O2
NaNO2 (1)
rest of equation (1)
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