TEST BANK [Edexcel International GCSE] Cliff Curtis - Edexcel Igcse Chemistry Revision Guide

1 a) electron b) electron
c) proton and neutron d) proton and electron
e) neutron
2 a) metals; non-metals; lost, gained; high; high
b) i) 2.8.2; 2.8.7 ii) 2.8; 2.8.8
3 a) Starting states – B; B; A; C Finishing states – A; C; C; A
b) B
c) element; mixture; mixture; compound
4 a) Atoms that have the same number of protons but different numbers of neutrons.
It is essential to include the word atom in your answer.
Alternative answer
Atoms with same atomic number but different mass numbers, or atoms of the same
element with different masses.
b) i) First row – 37; 48 Second row – 37; 87
ii)
(85 ! 71) + (87 ! 28)
100
= 85.6
c) They have the same electronic configuration.
Do not mention protons or neutrons in your answer.
Chemical reactions involve only electrons.
Alternative answer
Both have same number of electrons in the outer shell, or both have one electron in
the outer shell.
d) i) Rb2O; RbCl
ii) Any two from: • rubidium fizzes or bubbles or moves around
• rubidium disappears or dissolves
• rubidium melts or forms a ball
• rubidium catches fire or explodes or flame is produced
iii) 2Rb + 2H2O → 2RbOH + H2
5 a) Electrons within the structure are free to move.
b) Ions cannot move until the lead(II) bromide is a liquid.
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c) First reaction – B and reduction
Second reaction – A and oxidation
d) i) Amount of Pb = 0.05 mol; Amount of Br2 = 0.05 mol
ii) Mass of bromine = 0.05 x 160 g = 80 g
6 a) i) (39 + 16 + 1) = 56
ii)
14.0
56
= 0.25 mol
iii)
0.25 ! 1000
250
= 1.0 mol/dm3
b) i)
200
1000
! 2.0 = 0.40 mol
ii)
1
2
! 0.40 = 0.20 mol
iii) 0.20 ! 24 = 4.8 dm3
7 a) Allotropy
Allotropy is no longer on the specification.
b) Covalent. The attraction of each of the two nuclei for a shared pair of electrons.
c) Cutting or drilling.
d)
e) Both are giant structures containing lots of covalent bonds that have to be broken.
It requires a lot of energy to break these bonds.
8 a) The force of attraction between two nuclei and a pair of electrons shared between them.
b) simple; weak; molecules; low.
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c) i)
ii)
9 a) A magnesium atom loses two electrons to form a magnesium ion.
A fluorine molecule/ two fluorine atoms gain two electrons to form two fluoride ions.
b) Magnesium; loss of electrons is oxidation.
c) i) Na+ and F–
ii) NaF
d) Yellow
10 a) NaCl(s) and H2O(l)
b) i) Dilute nitric acid and aqueous silver nitrate.
ii) White precipitate.
iii) Diffusion.
c) i)
ii) (Simple) distillation.
11 a) (56 × 2) + (16 × 3) = 160
b) i)
320 ! 1000
160
= 2000
ii) 2 × 2000 = 4000
iii) 4000 × 56 = 224000 g = 224 kg
c) i) It restricts the capacity of the blood to carry oxygen.
ii) 5000 × 24 = 120000 dm3
d) Fe2O3 + 3CO → 2Fe + 3CO2
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e) i) Silicon dioxide (silica/sand)
ii) CaCO3 → CaO and CaO + SiO2 → CaSiO3
12 a) By heating.
b) i) Diffusion
ii) Ammonium chloride (NH4Cl)
iii) Ammonia particles move more quickly
iv) A – red; B – blue
13 a) Distillation
b) Evaporation
c) Filtration / decantation
d) Chromatography
e) Fractional distillation
14 a) i) (1 + 80) = 81
ii)
1.62
81
= 0.02
iii)
0.02
250
! 1000 = 0.08
iv) 0.08 x 81 = 6.48
b) i) HBr + NaOH → NaBr + H2O OR H+ + OH ¯ → H2O
ii) A proton is transferred from HBr to NaOH / OH ¯
iii)
20.0
1000
! 0.20 = 0.004(00)
iv) 20.0 × 2 = 40.0 cm3
v) Methyl orange – red to orange (allow yellow), OR
Phenolphthalein – colourless to pink (allow red)
15 a) i) Giant lattice of positive ions with delocalised electrons.
ii) Can be beaten or hammered into shape.
iii) The layers of ions can slide over one another.
b) The two fluorine nuclei are attracted to a shared pair of electrons.
c) i) 2.7 ii) 2.8
d)