Exam (elaborations) TEST BANK [Edexcel International GCSE] Cliff Curtis - Edexcel Igcse Chemistry Revision Guide Solutions Manual-Copy

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. Chemistry Revision Guide 2 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. 3 Chemistry Revision Guide 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 = g = 224 kg c) i) It restricts the capacity of the blood to carry oxygen. ii) 5000 × 24 = dm3 d) Fe2O3 + 3CO → 2Fe + 3CO2 Chemistry Revision Guide 4 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)