Chemistry · May / June 2021 · Paper 41 · Question 5
0620
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This question is about salts.
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5(a)[5]
(add) water (to both salts) (1)
dissolve both salts / make solutions (1)
filter (lead(II) iodide)(1)
wash (residue of lead(II) iodide) with water AND dry e.g. with filter paper / description of washing and drying (1) Pb(NO3)2 + 2 NaI → 2NaNO3 + PbI2
OR Pb2+ + 2I– → PbI2 (1)
5(b)(i)[2]
glowing splint (1)
relights / rekindles (1)
5(b)(ii)[2]
2ZnO(s) and 4NO2(g) (1)
12H2O(g) (1)
5(c)(i)[2]
heat again and weigh again / repeat steps 2 and 3 (1)
until mass is constant (1)
5(c)(ii)[4]
0.005 (1)
0.9 (1)
(0.9 ÷ 18 =) 0.05 (1)
(0.05 ÷ 0.005 =) 10 (1)
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