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Pearson Edexcel International A Level Chemistry Student Book 2 1st Edition Cliff Curtis
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.
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/dm 3
b) i) 200 1000 ! 2.0 = 0.40 mol
ii) 1 2 ! 0.40 = 0.20 mol
iii) 0.20 ! 24 = 4.8 dm 3
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.
c) i)
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
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)
16
a)
i) Left-hand electrode –; right-hand electrode + ii) H+; it is gaining electrons
iii) Horizontal line in right-hand tube halfway between the line given and the top of the tube. The same number of moles of electrons produce twice as many moles of hydrogen as oxygen.
b) i) 0.40 2 = 0.20
ii) (0.20 × 24) = 4.8 dm3
c) i) 0.80 4 = 0.20
ii) (0.20 × 32) = 6.4 g
Section B: Chemistry of the Elements
1 a) Atomic number
c) Group 1
e) 3 or 4 or 5
2 a) i) Calcium / Ca2+
ii) Turns limewater milky
iii) Carbonate / CO32-
b) i) Fe2+
iii) Sulfate / SO42-
c) Any two from chloride, bromide and iodide
d) i) CaCO3
3 a) X
c) Re-lights a glowing spill
4 a) i) 5
b) i) NH3 + HCl → NH4Cl OR NH3 + H+ → NH4+
b) Relative atomic mass
d) Group 6
ii) Iron(II) hyrdoxide
iv) BaSO4
ii) FeSO4
b) 21
d) Carbon dioxide
ii) Colourless
ii) Add sodium hydroxide solution and warm. The gas given off turns damp red litmus paper blue.
iii) Add 15 cm3 of ammonia solution to 25 cm3 of hydrochloric acid. Leave the solution to evaporate.
Dry the crystals with filter paper.
c) i) Lead(II) nitrate and any soluble chloride, such as sodium chloride or hydrochloric acid.
c) Increase the temperature; increase the pressure / concentration of the gases; add a catalyst.
d) i) ⇌ reversible reaction; ΔH enthalpy change / heat energy change of reaction.
ii) Pressure increased – amounts decrease
Temperature decreased – amounts decreased
Section E: Chemistry in Society
1 a) i) Nitrogen – air; hydrogen – natural gas
ii) 450°C and 200 atmospheres pressure
iii) It is liquefied
iv) Re-cycled
b) NH3 + HNO3 → NH4NO3
2 a) Bitumen – making roads / making roofs; kerosene – jet aircraft fuel
b) i) Gasoline + oxygen → carbon dioxide + water
ii) Shortage of oxygen / air
iii) Carbon monoxide is produced. Carbon monoxide is poisonous as it reduces the capacity of blood to carry oxygen.
c) Heat the crude oil in a round-bottomed flask. Use a thermometer to measure the temperature of the vapours distilling over and collect those between 80°C and 120°C. Condense the vapours by passing them through a Liebig condenser.
3 a) Hydrogen and carbon.
b) They condense at different heights according to their different boiling points.
c) Gasoline – petrol for cars; Bitumen – making roads / making roofs
d) Any two from: refinery gases, kerosene, diesel, fuel oil.
e) i) Carbon dioxide and water
ii) Carbon monoxide is produced. Carbon monoxide is poisonous as it reduces the capacity of blood to carry oxygen.
4 a) i) Limestone and coke.
ii) Slag / calcium silicate
iii) C(s) + O2(g) → CO2(g)
iv) CO2
b) i) Oxygen and water.
ii) Zinc. The coating of zinc prevents the iron from coming into contact with water and oxygen.
OR
Zinc is more reactive than iron and therefore corrodes in preference to the iron.
iii) It is coated in oil.
5 a) i) Limestone ii) Coke
iii) Iron ore (in any order) iv) Molten slag
v) Molten iron
b) i) Reaction 1 ii) Carbon dioxide; it loses oxygen
c) It is poisonous / toxic
d) It is too reactive / it is more reactive than carbon / it cannot be reduced by carbon monoxide.
6 a) i) Electrolysis
ii) Carbon / graphite
iii) A is +; B is iv) Aluminium oxide and cryolite
v) Electricity
b) i) Oxygen
ii) Carbon dioxide / carbon monoxide. Formed when the electrode reacts with the oxygen produced.
