Unclassified Entries (1506)

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N22 2(c)(iii): air (1) reduced (1) dioxide (1) slag (1)
iN18 7(d)(ii): air (1) monoxide (1) decomposes (1) slag (1)
iJ21 3(a)(i): melting point of Cl any values between –215 and –30 (°C) (inclusive of these values) (1) colour of At: black / grey-black (1) density of F: any values between 0.1 and 1.5 (nm) (inclusive of these valu
iM16 4(b)(ii): 3(H2); 2(NH3);
iM16 6(e)(i): 2(C2H5OH) 2(CO2)
iM16 6(e)(iii): 180; one row correct = [1], e.g. 12 × 1 = 12 or 6 × 16 = 96
iJ17 4(a)(v): 160 IF full credit is not awarded, allow 1 mark for (Fe =) 56 and (O =16)
J24 3(d)(iii): blue (1) to colourless (1)
J24 5(b)(ii): SO2 (1) 2 (MgO) (1)
J24 6(c)(i): pressure: (rate) decreases / slower (reaction) (1) catalyst: (rate) increases / faster (reaction) (1)
J19 4(d)(i): 2 (Na2S2O3) (1) 2 (NaI) (1)
iJ16 2(c)(i): breakdown of an ionic compound by the passage of electricity (1 mark for breakdown of a compound by the passage of / using electricity)
N22 2(c)(i): 3 (Fe) (1) 2 (O2) (1)
N22 4(a)(i): density of iodine: values between 3.2 and 6.2 (inclusive of these values) (1) boiling point of astatine: values between 305 and 1000 (inclusive of these values) (1)
N22 4(b)(i): 2 (H2O) (1) 2 (HBr) (1)
N22 6(d)(ii): step 3 filter (the mixture) (1) step 6 dry crystals on filter paper / dry crystals in drying oven (1)
iN15 3(b)(iii): 2Br– → Br2 + 2e– / 2Br– – 2e– → Br2 formulae; balancing;
iN15 5(d)(ii): 2NaOH + H2SO4 → Na2SO4 + 2H2O Na2SO4; rest of equation correct; or H+ + OH– → H2O H2O as the only product on the right hand side; rest of equation correct; or NaOH + H2SO4 → NaHSO4 + H2O NaHSO4; rest
J23 7(b)(ii): aqueous bromine (1) turns colourless / decolourises (1)
iN16 6(a)(iii): any 2 from: • density increases • melting / boiling point decreases • hardness decreases • reactivity increases
J21 3(a)(i): boiling point of Rb: any values between 675 and 755 (°C) (inclusive of these values) (1) atomic radius of K: any values between 0.195 and 0.245 (nm) (inclusive of these values) (1)
J21 6(b)(i): nitrogen (1) oxygen (1)
J21 6(b)(ii): large(r) particles cannot get through (the small gaps in) the filter / large(r) particles get trapped in the filter / large(r) particles too big to get through (filter) (1) water passes through (1)
J20 4(b)(i): lighted splint pops / explodes
J20 6(b)(ii): larger pieces: decreases (rate) increasing temperature: increases (rate)
J20 7(e)(i): H H I I H – C – C – O – H I I H H
J20 7(e)(ii): steam catalyst
iN17 2(d)(ii): 98 IF full credit is not awarded, award 1 mark for (S =) 32 , (O = 16) and (H =1)
iN17 3(d)(i): structure completed correctly with all of the atoms and all of the bonds IF full credit is not awarded, award 1 mark for OH instead of O–H
N24 7(b)(ii): (H+) + OH– → H2O OH– (1) H2O (1)
iJ22 3(b)(iii): Cl2 (1) 2 (NaCl) (1)
iJ22 3(c)(iii): 1 mark each for any two of:  low(er) density (1)  low(er) melting point (1)  soft(er)
iJ21 2(c)(i): potassium (1) nitrogen (1)
iJ21 7(c)(i): separation: far apart / far away (from each other) / distant (from each other) (1) motion: rapid / unrestricted / random (1)
iJ21 8(b)(i): giant (structure) (1) covalent (bonding) (1)
iJ20 4(b)(i): lighted splint pops / explodes
iJ20 6(b)(ii): larger pieces: decreases (rate) increasing temperature: increases (rate)
iJ20 7(e)(i): H H I I H – C – C – O – H I I H H
iJ20 7(e)(ii): steam catalyst
iN18 3(b)(ii): nitrogen dioxide / NO2 (1) lightning / high temperature furnaces (1)
iN18 4(a)(ii): orange / red-brown (1) to colourless / decolourised (1)
iN24 7(a)(iii): one mark each for any two of: • heat to point of crystallisation / heat to form saturated solution • filter off crystals / pick out crystals • dry with filter paper
iN20 4(c)(ii): breakdown of a compound (1) by heating / by high temperature (1)
iN20 5(d)(ii): fractional (1) distillation (1)
iN20 8(a)(ii): R: freezing (1) S: boiling / evaporation (1)
iJ19 2(c)(i): 2 (Fe) (1) 3 (Cl2)
iN22 2(d)(i): calcium oxide (1) oxygen (1)
iN22 4(a)(i): boiling point of sodium: values between 770 and 1300 (inclusive of these values) (1) hardness of rubidium: values between 0.1 and 0.35 (inclusive of these values) (1)
iN22 4(b)(i): 2 (Na) (1) 2 (Na2O) (1)
iN22 4(b)(ii): lighted splint (1) pops / explosion (1)
iN22 6(c)(i): from red / pink (1) to yellow (1)
iM18 2(c)(ii): 46 If 2 marks not obtained: 1 mark for 1 row all correct e.g. hydrogen 6 × 1 = 6 oxygen 1 × 16 = 16
iM18 4(e)(i): one mark each for any two of: • high temperature • catalyst • high pressure max
iM19 4(b)(iii): steeper gradient starting at 0-0 (1) ends up at same volume (70 cm3) (1)
iM19 4(b)(iv): decreases rate / goes slower (1) increases rate / goes faster (1)
iM20 6(b)(ii): large pieces: (rate) decreases / gets slower / slows down (1) increasing temperature: (rate) increases / gets faster (1)
iM20 8(d)(i): Cl2 (on left) (1) 2 (KCl) (on right) (1)
iM22 4(a)(i): sodium nitrate (1) (and) water (1)
iM22 5(a)(i): G is oxygen (1) H is nitrogen (1)
iM22 5(b)(i): oxides of nitrogen: breathing difficulties / irritates lungs / irritates eyes / irritates throat / irritates skin / lung problems (1) lead compounds: poisonous / toxic / harms nervous system / harms b
iM22 6(a)(i): boiling point of Na any values between 800 and 1300 (°C) (inclusive of these values) (1) hardness of Li: any value above 0.70 (MPa) up to a maximum of 5.0 (MPa) (1)
iM22 7(b)(ii): breakdown of a compound (1) using heat / by heat (1)
iM22 8(c)(i): 2 (P) (1) 5 (Cl2) (1)
iM22 8(d)(i): bromine (1) sodium chloride (1)
iM23 7(c)(ii): air / oxygen (1) water (1)
iM23 7(d)(ii): 1 mark each for any 2 of: • evaporate to point of crystallisation / evaporate until saturated solution formed • leave to crystalise • filter off crystals / pick out crystals • dry with filter paper
iM23 8(a)(ii): steeper initial gradient starting at 0-0 (1) line levels off at 44 cm3 (1)
iM17 1(a)(i): oxygen / O2
iM17 2(a)(i): A placed either on the left hand lower tube (or on the one on the right directly opposite this) 1 W placed on both or either of the tubes at the top
iM17 2(b)(i): breakdown of a substance / breakdown of a compound 1 using heat / using high temperature
iM17 2(b)(ii): CO2
iM17 2(d)(ii): conducts electricity / inert
iM17 3(b)(ii): oxygen on left 1 water on right
iM17 3(c)(i): increases as the number of carbon atoms increases
iM17 3(c)(ii): pentane / C5H12 1 20 °C is in between its melting and boiling points / boiling point is above 20 °C and melting point is below 20 °C
iM17 5(c)(i): double C=C bond
iM17 6(f)(i): 1.8 g
iM16 1(a)(i): N / nitrogen;
iM16 1(b)(i): substance containing only one type of atom;
iM16 1(b)(iii): 18;
iM16 2(b)(i): they are inert / they do not react;
iM16 4(b)(i): speeds up (rate of) reaction;
iM16 5(d)(i): ⇋;
iM16 7(d)(ii): water;
iM16 7(d)(iii): potassium carbonate;
iJ17 2(a)(i): 8 (mg)
iJ17 2(a)(ii): hydrogencarbonate / HCO3 –
iJ17 2(a)(iii): nitrate
iJ17 2(a)(iv): 12.5 (mg)
iJ17 4(a)(iii): 2 (Fe) 1 3 (CO2)
iJ17 4(b)(i): hydrogen / H2
iJ17 4(b)(ii): gas syringe connected to flask OR this described in words 1 closed apparatus / workable apparatus OR this described in words 1 timer / stop-watch OR this described in words
iJ17 5(e)(i): decreases with an increasing number of carbon atoms ORA
iJ17 5(e)(ii): any value between 118 and 164 (°C) (exclusive of these values)
iJ17 6(a)(i): J it is (very) strong / it is the strongest 1 it is cheap
iJ17 6(a)(ii): M because it is the hardest
iJ17 6(a)(iii): K because its density is the lowest
iJ17 6(b)(i): line at a steeper gradient than W 1 ends up at same mass loss
iJ17 6(b)(iii): 1.05 days
iJ17 7(d)(i): water 1 air / oxygen
J24 3(d)(i): H+
J24 3(d)(ii): hydrogen
J24 4(a)(i): H H │ │ C = C │ │ H H
J24 8(a)(i): increases with the number of carbon atoms / increases down the series
J24 8(a)(ii): CnH2n+1COOH
J24 8(b)(ii): CH3COONa
J24 8(c)(ii): covalent
J19 1(a)(ii): D / nitrogen / N2
J19 2(d)(i): thermal decomposition
J19 3(a)(i): 5.0%
J19 3(a)(ii): oxygen
J19 5(b)(iii): cannot be decomposed by organisms / cannot be broken down by bacteria / cannot be broken down by fungi
J19 5(b)(iv): gets stuck in gullets of birds / gets stuck in gullets of animals / blocks drains
J19 6(b)(i): reversible reaction
J19 6(b)(ii): heat / warm
J19 7(b)(i): gas released / gas escapes / gas lost
J19 7(b)(ii): 0.7 (g)
J19 7(b)(iv): 0.22 (g)
J19 7(b)(v): large pieces → 0.005 small pieces → 0.030 powder → 0.100
iJ16 1(a)(i): C and E;
iJ16 1(a)(ii): B;
iJ16 1(a)(iii): B;
iJ16 1(a)(iv): B;
iJ16 1(a)(v): C5H5Cl 5 / CHCl;
iJ16 3(a)(i): black / grey-black / grey;
iJ16 3(b)(i): potassium bromide; astatine; 2 1
iJ16 4(c)(ii): 52%;
iJ16 4(c)(iii): A;
iJ16 4(d)(i): high temperature / heat;
iJ16 6(d)(ii): 32%;
iJ16 6(e)(ii): any suitable use, e.g. fuel / solvent;
iJ16 7(b)(ii): 3 minutes / 180 s (unit required);
iJ16 7(b)(iii): line of steeper gradient than the one shown on the grid and starting at (0, 0); line ends at the same volume as the one shown on the grid but reaches this volume sooner; 2 1
iJ15 4(a)(ii): propanol / propan-1-ol / propan-2-ol;
N22 2(a)(i): 3.5 (%)
N22 2(a)(ii): oxygen
N22 2(d)(ii): basic oxide
N22 4(b)(ii): loss of oxygen
N22 5(b)(i): vehicle engines / high temperature furnaces / lightning
N22 5(b)(ii): breathing difficulties / asthma
N22 6(e)(i): 40 60 20
N22 6(e)(ii): time taken is less / shorter
N22 7(a)(ii): C5H10O2
N22 7(b)(i): (substance that) speeds up a reaction / (substance that) increases the rate of a reaction / (substance that) makes the reaction go faster
N22 7(c)(i): H H │ │ C = C │ │ H H
N22 7(c)(ii): far apart
iN15 3(a)(i): vibrate (about fixed position) / vibration;
iN15 3(a)(iii): regular / repeated / pattern / framework / ordered / alternating / organised (arrangement of); positive and negative ions / oppositely charged ions / cations and anions / unlike charged ions; 1
iN15 3(b)(ii): Li+ + e– → Li / Li+ → Li – e–;
iN15 4(c)(i): 150 (cm3);
iN15 4(c)(ii): 100 (cm3);
iN15 4(c)(iii): This question was discounted.
iN15 5(b)(iii): Br2 + 2e– → 2Br– / Br2 → 2Br– – 2e–;
J22 1(a)(i): CO2
J22 1(a)(ii): K+
J22 1(a)(iii): O2
J22 1(a)(v): Br-
J22 2(a)(iii): 6.4 (g)
J22 2(d)(i): H H │ │ H─C─C─O─H │ │ H H
J22 2(d)(iii): fuel / solvent
J22 4(d)(ii): reactants on top left horizontal line and products on bottom left horizontal line
J22 5(c)(i): bauxite
J22 6(a)(i): D and E
J22 7(a)(ii): density is low(er) / melting point is low(er) / soft
J23 2(a)(i): values between 115 °C and 335 °C (inclusive of these values)
J23 2(a)(ii): values between 4.95 and 15.0 (inclusive of these values)
J23 3(a)(ii): deoxygenation of water / remove oxygen from water
J23 3(b)(ii): nitrate
J23 3(b)(iii): 0.4 (mg)
J23 3(c)(i): add water
J23 4(c)(ii): Cl2 + H2 on left horizontal line AND 2HCl on right horizontal line
J23 4(c)(iii): the energy of the reactants is greater than the energy of the product / the energy of Cl2 + H2 is greater than the energy of HCl / the energy of the products is less than the energy of the reactants
J23 4(e)(ii): OH-
J23 5(a)(i): hematite
J23 6(a)(i): medium small large
J23 6(a)(ii): takes shorter time / less time taken
J23 7(a)(ii): C5H6O5
J23 7(c)(ii): C8H18
J23 8(b)(ii): CnH2n+2
J23 8(b)(iii): decomposition of vegetation / waste gases from digestion in animals
iN16 1(a)(i): O / oxygen
iN16 1(a)(iv): Br / bromine
iN16 2(a)(iii): 0.5 (g)
iN16 2(c)(i): filtration / filter
iN16 2(c)(ii): carbohydrate AND protein
iN16 3(b)(ii): values between 125(°C)–145 (ºC) inclusive
iN16 3(b)(iii): increases with (increasing) number of carbon atoms
iN16 5(a)(ii): arrow(s) pointing in both directions / ⇌
iN16 5(b)(i): C in or just outside the tube at the top left L in or just outside the tube at the bottom right 1
iN16 5(b)(ii): to produce a high temperature / for heat(ing)
iN16 5(d)(ii): SiO2 / Si6O12
iN16 5(e)(ii): H2O
iN16 6(c)(ii): one pair of bonding electrons between H and Cl 6 non-bonding electrons around Cl and none around H 1
J21 2(a)(i): Cl – / chloride
J21 2(a)(ii): NH4+ AND SO42-
J21 2(a)(iii): 24 (mg)
J21 3(a)(ii): decreases (1)
J21 3(b)(ii): any suitable, e.g. detecting leaks in pipes / measuring thickness of paper / energy production
J21 4(a)(ii): C4H6O5
J21 4(e)(ii): 18 (cm3)
J21 6(b)(iii): to kill bacteria / to kill micro-organisms
J21 7(a)(ii): platinum (1)
J20 1(a)(ii): H2 / hydrogen
J20 1(a)(iii): N2 / nitrogen
J20 1(a)(v): Cl - / chloride
J20 2(a)(iii): 5.6 (mg)
J20 4(b)(ii): C5H10O2
J20 5(b)(i): inert / unreactive
J20 7(c)(i): filtration / filtering
iN17 1(b)(i): burning fossil fuels / volcanoes / high temperature furnaces / burning named fossil fuel
iN17 1(b)(ii): breathing difficulties / irritates nose / irritates eyes / irritates throat
iN17 2(c)(iii): it has 8 electrons in its outer shell
iN17 2(e)(i): bleach / treating wood pulp / preservative
iN17 3(c)(i): H2
iN17 3(c)(ii): filtration / filter
iN17 4(d)(i): low density
iN17 4(f)(ii): drill (bits) / jewellery
iN17 5(f)(ii): cutlery / chemical plant
iN17 6(c)(ii): 3 (H2)
iN17 6(c)(iii): takes in heat (from surroundings) / absorbs heat / absorbs thermal energy
iN17 6(e)(i): (boiling point) increases
iN17 6(e)(ii): any value between –8 and –80 (°C) inclusive of these values
N24 1(a)(ii): Al
N24 1(a)(iv): Ba
N24 1(a)(v): Al
N24 1(a)(vi): Au
N24 1(b)(i): has (only) one atom
N24 2(a)(ii): electrons
N24 2(c)(i): cutting (tools)
N24 3(c)(i): hydrogencarbonate
N24 3(c)(ii): nitrate
N24 3(c)(iii): 0.4 (mg)
N24 3(d)(i): to remove solids
N24 3(d)(i): to kill (harmful) microbes
N24 4(a)(ii): C4H6O5
N24 4(d)(ii): CnH2n
N24 4(d)(iii): increases
N24 5(a)(i): values between 116 °C and 335 °C (inclusive of these values)
N24 5(a)(ii): values between 0.05 and 1.55 g / cm3 (inclusive of these values)
N24 6(b)(ii): 2,8,1
N24 7(a)(i): aqueous / dissolved in water
N24 7(a)(ii): filtration
N24 7(b)(iii): release of thermal energy
N24 7(b)(iv): the energy of the products is lower than the energy of the reactants OR the energy of the reactants is higher than the energy of the products
N24 8(a)(i): 1.0 0.5 2.0
N24 8(a)(iii): shorter time / decreases time / less time
iJ22 1(a)(i): He
iJ22 1(a)(ii): Li+
iJ22 1(a)(iii): H2
iJ22 1(a)(iv): CO2
iJ22 1(a)(v): O2-
iJ22 2(a)(iii): 0.55 (g)
iJ22 3(b)(i): yellow-green (1)
iJ22 4(c)(ii): reaction which absorbs thermal energy / reaction which absorbs heat
iJ22 4(c)(iii): The energy of the reactants is lower than the energy of the products / the energy of the products is higher than the energy of the reactants
iJ22 5(d)(i): reversible reaction
iJ22 5(d)(ii): bleach / manufacture of wood pulp / making paper / food preservative
iJ23 2(a)(i): values between –100 °C and +10 °C (inclusive of these values)
iJ23 2(a)(ii): values lower than 0.003
iJ23 3(a)(ii): contains harmful microbes
iJ23 3(b)(iii): 0.55 (mg)
iJ23 3(c)(i): heat
iJ23 3(c)(ii): hydrated
iJ23 4(b)(i): 2HBr on left horizontal line AND H2 + Br2 on right horizontal line
iJ23 4(b)(ii): the energy of the reactant is lower than the energy of the products / the energy of HBr is lower than the energy of H2 + Br2/ the energy of the products is greater than the energy of the reactants
iJ23 4(b)(iii): surroundings
iJ23 4(c)(i): H+
iJ23 4(c)(iii): red / pink
iJ23 6(a)(i): 40 °C 20 °C 30 °C
iJ23 6(a)(ii): takes shorter time / less time taken
iJ23 7(a)(i): circle around C=C bond
iJ23 7(a)(ii): C4H8O
iJ23 7(b)(i): CnH2n+1OH
iJ23 7(b)(ii): H H │ │ H – C – C – O – H │ │ H H
iJ23 8(c)(iii): a substance that dissolves a solute
iJ21 2(a)(i): Cl – / chloride
iJ21 2(a)(ii): Na+ AND NO3–
iJ21 2(a)(iii): 1.5 (mg)
iJ21 3(c)(i): (the number of nucleons) decreases (1)
iJ21 4(b)(i): C8H14O4
iJ21 4(c)(ii): 23 (cm3)
iJ21 5(a)(i): limestone
iJ21 5(c)(ii): measuring cylinder
iJ21 6(b)(ii): lamps / light bulbs
iJ21 8(b)(ii): it is hard (1)
iJ20 1(a)(ii): H2 / hydrogen
iJ20 1(a)(iii): N2 / nitrogen
iJ20 1(a)(v): Cl - / chloride
iJ20 2(a)(iii): 5.6 (mg)
iJ20 4(b)(ii): C5H10O2
iJ20 5(b)(i): inert / unreactive
iJ20 7(c)(i): filtration / filtering
iN18 2(a)(ii): 3.9 (g)
iN18 3(d)(ii): add water
iN18 4(a)(i): C=C (double bond)
iN18 4(a)(iv): turns it red / pink
iN18 4(b)(iii): 14 cm3
iN18 5(d)(iii): bubbles / strong smell (of chlorine)
iN18 7(b)(i): any value between 5.0 and 5.5 min (inclusive)
iN18 7(b)(ii): 96 cm3
iN18 8(a)(ii): (chlorine is a) gas (at room temperature)
iN18 8(b)(i): to kill bacteria
iN24 1(a)(i): Zn 1 1a(ii) Ca
iN24 1(a)(iv): Al
iN24 1(a)(v): Fe
iN24 2(a)(i): 21 (%)
iN24 3(c)(i): tin
iN24 3(c)(iii): 0.8 (mg)
iN24 4(a)(ii): C3H7NO3
iN24 4(c)(ii): CnH2n+1OH
iN24 4(c)(iii): Increases
iN24 4(d)(ii): H H │ │ H – C – C – O – H │ │ H H
iN24 5(a)(i): values between 116 °C and 335 °C (inclusive of these values)
iN24 5(a)(ii): values less than 22.7 (cm3 / mol) but not below 1.0
iN24 6(b)(ii): 2,8,8,2
iN24 7(a)(i): (l)
iN24 7(a)(ii): filtration
iN24 7(c)(i): thermal energy is released (in the reaction) / (reaction that) transfers thermal energy / (reaction that) gives out heat
iN24 7(c)(ii): ZnO + (2)HCl on the line on the left AND ZnCl2 and H2O on the line on the right
iN24 8(a)(i): 0.8 1.6 0.4
iN20 1(a)(i): H / H2 / hydrogen
iN20 1(a)(ii): Cl / chlorine / Cl 2
iN20 2(a)(ii): 26.5 (ng)
iN20 2(b)(i): oxygen is not in excess / oxygen is limiting / there is excess carbon / there is excess fuel
iN20 2(b)(ii): poisonous / toxic / kills you
iN20 2(d)(ii): reactants on left top line and products on bottom right line
iN20 4(a)(ii): C4H6O2
iN20 7(b)(i): decreases (as time increases)
iN20 7(b)(ii): 60 s
iN20 8(e)(i): add water (1)
iJ18 1(a)(i): chlorine / Cl 2
iJ18 1(b)(ii): shared pair of electrons (between two atoms)
iJ18 2(a)(i): 72 (%)
iJ18 2(a)(ii): hydrogen / H2
iJ18 2(b)(i): breathing difficulties / irritates nose / irritates eyes / asthma attacks
iJ18 2(b)(iii): sodium nitrate
iJ18 4(c)(ii): 4 (HCl ) 1 2 (H2O)
iJ18 5(a)(iv): carbon / platinum
iJ18 5(b)(i): 150 (g)
iJ18 7(a)(ii): it is a gas (at room temperature)
iJ18 8(d)(i): oxygen (on left) 1 water (on right)
iJ18 8(e)(ii): arrangement: in layers / regular / lattice 1 motion: (only) vibrating
iJ19 2(a)(i): hematite
iJ19 2(a)(iii): energy (level) of the products is greater than the energy of the reactants
iJ19 2(c)(ii): reversible reaction
iJ19 3(a)(i): 0.7 (%)
iJ19 5(b)(ii): last box ticked
iJ19 5(d)(i): water / H2O
iJ19 5(e)(ii): clothing
iJ19 6(b)(i): 2nd box down ticked (decomposition)
iJ19 6(b)(ii): 31.7 (g)
iJ19 7(b)(i): any value between and including 92–102 s
iJ19 7(b)(ii): 34 (cm3)
iJ19 7(b)(iv): increases rate / goes faster
iJ19 7(b)(v): decreases rate / goes slower
iJ19 8(a)(ii): brain damage (in children) / damage to nervous system
iN22 1(c)(i): combustion in limited oxygen / combustion in limited air / not enough air to burn completely
iN22 2(a)(i): 0.9 (%)
iN22 2(a)(ii): oxygen
iN22 2(c)(ii): 2 (CO)
iN22 2(c)(iii): loss of oxygen (from a compound)
iN22 2(c)(iv): 20 (g)
iN22 3(b)(i): refinery gases / kerosene / fuel oil
iN22 3(b)(ii): boiling point
iN22 3(b)(iii): X drawn next to bottom right-hand arrow
iN22 3(c)(i): uranium
iN22 5(b)(i): reversible reaction
iN22 5(b)(ii): 78 (%)
iN22 5(d)(ii): chemical weathering / erosion / pitting of surface
iN22 6(b)(i): very small large small
iN22 6(b)(ii): takes longer / time increases
iN22 6(d)(ii): increases reaction rate / makes the reaction go faster / speeds up the reaction
iN22 7(a)(ii): C4H6O2
iN22 7(a)(iii): regular / ordered (1)
iN22 7(c)(ii): protein
iN22 7(c)(iii): block drains / litter / (fills) landfill (sites) / poisonous fumes given off when burned
iN22 8(a)(ii): electrical wiring
iM18 1(a)(i): E / oxygen / O2
iM18 1(a)(iii): E / oxygen / O2
iM18 2(a)(i): 25 (mg)
iM18 2(b)(ii): C3H6O3
iM18 2(c)(i): removal of oxygen (from a compound)
iM18 3(b)(i): density of fluorine: ALLOW: values lower than 1.56 (but not 0 or negative numbers) 1 melting point of chlorine: ALLOW values between –220 and –7 ºC (excluding these two values)
iM18 4(e)(ii): C11H24
iM18 5(a)(ii): chlorine
iM18 5(a)(iv): argon / krypton / xenon
iM18 5(b)(iii): cobalt AND nickel
iM18 7(b)(iv): 4th box down ticked
iM18 8(a)(i): decreases (rate) / slower (rate)
iM18 8(a)(ii): decreases (rate) / slower (rate)
iM18 8(a)(iii): increases (rate) / faster (rate)
iM18 8(b)(i): hematite
iM19 2(a)(ii): energy production
iM19 3(a)(i): Br– / bromide
iM19 3(a)(ii): potassium bromide
iM19 3(a)(iii): 11 (mg)
iM19 3(a)(iv): e–
iM19 3(c)(i): idea of solid turning (directly) to gas
iM19 4(b)(i): 54 (cm3)
iM19 5(d)(i): from car engines / lightning / high temperature furnaces
iM19 5(d)(ii): irritates eyes / nose / mouth / skin / lungs
iM19 6(b)(ii): energy of reactants greater than energy of products
iM19 6(d)(ii): spoon silvery in colour
iM19 7(a)(i): increases as number of carbon atoms increases / decreases as number of carbon atoms decreases
iM19 7(a)(ii): propane
iM21 2(a)(i): B3O63– / metaborate
iM21 2(a)(ii): K+ AND SO42–
iM21 2(a)(iii): 80 (mg)
iM21 2(a)(v): bromide
iM21 2(d)(i): cancer treatment / tracer (e.g. for thyroid function)
iM21 3(a)(ii): increases
iM21 3(b)(i): 2,7
iM21 5(c)(i): C + (2)S on lower line to left AND CS2 on upper line to right (1)
iM21 5(c)(ii): the product energy level is above the reactant energy level
iM21 5(f)(ii): food preservation / food preservative
iM21 6(a)(iii): C5H8O3
iM21 6(a)(iv): has a C=C double bond
iM20 1(a)(i): potassium manganate(VII)
iM20 1(a)(iii): potassium iodide / iodide
iM20 1(a)(iv): calcium oxide
iM20 2(d)(ii): 2.8 (g)
iM20 4(a)(ii): C5H8O2
iM20 5(d)(ii): lilac
iM20 6(a)(i): transfers thermal energy to surrounding / transfers heat to surroundings / gives out heat
iM20 6(a)(iii): combustion
iM20 8(a)(ii): ionic
iM22 2(a)(i): 1 (%)
iM22 3(b)(iii): cutlery / chemical plant / surgical equipment
iM22 5(a)(ii): volume increases (as temperature increases)
iM22 5(a)(iii): they have a full outer shell (of electrons) / they have a complete outer shell (of electrons)
iM22 6(c)(ii): inert / unreactive
iM22 7(a)(iv): C4H8O2
iM22 8(c)(ii): releases thermal energy / releases heat
iM23 2(b)(i): chloride / Cl –
iM23 2(b)(iii): 3.1 (mg)
iM23 3(b)(i): car engines / car exhausts / vehicle exhausts
iM23 4(c)(i): Mg + Cl2 on line on left AND MgCl2 on line on right
iM23 4(c)(ii): the energy of the reactants is greater than the energy of the products / the energy of the products is less than the energy of the reactants
iM23 5(d)(i): I2
iM23 5(d)(ii): displacement
iM23 5(d)(iii): (pale) yellow-green
iM23 6(d)(i): covalent
iM23 6(d)(ii): H H │ │ H – C – C – H │ │ H H
iM23 7(a)(i): hematite
iM23 7(c)(i): (substance) chemically combined with water
iM23 8(a)(i): 27 (cm3)
iM23 8(b)(i): (rate) decreases / reaction slows down
iM23 8(b)(ii): (rate) decreases / reaction slows down
iM23 8(c)(ii): H+
iM17 6(f)(ii): 315 g 1
iM17 7(c)(ii): energy (production) / nuclear power 1
iM16 6(c)(ii): filtration; 1
iJ17 2(d)(ii): platinum / Pt 1
J24 6(b)(ii): 1.
J24 8(c)(iii): combustion (1) substitution with chlorine (1) 2
iJ16 1(b)(ii): 8; 1
iJ16 4(d)(ii): C5H10; 1
iJ16 6(e)(iii): 2 (CO2); 3 (H2O); 2 1 1
iJ16 7(d)(iii): preservative / bleach / papermaking / wine-making; 1
iJ15 2(b)(i): Any one from: (making) car (bodies); machinery; chains; pylons; white goods; nails; screws; as a building material; sheds / roofs; reinforcing concrete; 1 A bridges A tools I cutlery
iJ15 2(b)(ii): Any one from: knives; drills; railway tracks; machine / cutting tools / hammers; razor blades; chisels; 1 I cutlery items I bridges
iJ15 4(c)(ii): butyl ethanoate; 1 A butanyl R ethenoate and ethanoic
iN15 5(d)(i): 2NH3 + H2SO4 → (NH4)2SO4 / NH3 + H2SO4 → (NH4)HSO4; 1
iN15 5(d)(iii): Fe + H2SO4 → FeSO4 + H2; FeSO4; rest of equation correct; or Fe + 2H+ → Fe2+ + H2; Fe2+; rest of equation correct; or 2Fe + 3H2SO4 → Fe2(SO4)3 + 3H2; Fe2(SO4)3; rest of equation correct; or 2Fe + 6H+
J22 3(d)(ii): brown 1
J22 6(a)(iii): C 1
J23 4(c)(i): reaction that transfers thermal energy / reaction that gives out heat (1) to the surroundings (1) 2
J23 7(a)(iii): has a C=C bond / has a carbon – carbon double bond 1
iN16 2(c)(iii): random / zigzag / go anywhere / irregular 1
iN16 6(c)(i): H2 (on left)
J21 3(c)(i): 2 (Fe) (1) 3 (NaOH) (1) 2
J21 5(b)(i): gas syringe / upturned measuring cylinder dipping into container (1) apparatus is workable and airtight (1) 2
J20 5(c)(ii): red-brown 1
iN17 5(f)(i): car bodies / bridges / railings 1
iJ22 4(c)(iv): 24 (cm3) 1
iJ22 6(a)(iv): D 1
iJ23 4(d)(iii): conducts electricity / inert 1
iJ21 2(d)(i): 2 (NaOH) (1) 2 (NH3) (1) 2
iJ21 5(c)(iii): gas syringe 1
iJ20 5(c)(ii): red-brown 1
iN24 2(b)(ii): 4th box down ticked (strong electrostatic attraction between cations and anions) 1
iN20 2(d)(i): 2 (CO) (on left) (1) 2 (CO2) (on right) (1) 2
iN20 7(a)(i): idea of greater values for volume than mass lost / in method 2 mass of flask decreases only slightly / I method 2 idea of small decreases in mass involved / in method 2 mass loss too small (to measure
iN20 8(e)(ii): hydrated (1) 1
iN22 1(c)(ii): poisonous / toxic
iN22 3(c)(ii): testing for leaks in pipes / measuring paper thickness 1
iN22 7(b)(i): H H │ │ H – C – C – O – H │ │ H H 1
iM21 2(d)(ii): source of energy / energy production 1
iM22 2(c)(i): 2 (H2S) (1) 3 (O2) (1) 2
iM22 5(a)(iv): arrangement: irregular / random (1) separation: far apart (1) 2
iM23 6(a)(iii): C4H8O 1
iM23 6(d)(iv): 2 (O2) (1) CO2 (1) 2
iM23 7(d)(i): filtration / filter 1
iM23 8(c)(iv): yellow 1
ij15 2(b)(i): Any one from: (making) car (bodies); machinery; chains; pylons; white goods; nails; screws; as a building material; sheds / roofs; reinforcing concrete; 1 A bridges A tools I cutlery
ij15 2(b)(ii): Any one from: knives; drills; railway tracks; machine / cutting tools / hammers; razor blades; chisels; 1 I cutlery items I bridges
ij15 2(b)(iii): M1 atoms or cations or (positive) ions or metal ions; M2 arranged in a lattice or in layers or in rows or in a regular structure; M3 rows or layers slide over one another; 3 I (sea of) electrons R pro
ij15 2(b)(iv): M1 carbon atoms or particles in structure different size (to cations); M2 so reduce moving or interrupt movement; 2 R ions and molecules for M1 A M2 for prevents sliding A M2 for ‘stops’ sliding
ij15 4(a)(ii): propanol / propan-1-ol / propan-2-ol;
ij15 4(c)(ii): butyl ethanoate; 1 A butanyl R ethenoate and ethanoic
ij15 5(c)(ii): Any two from: (a reaction) M1 which can take place in both directions OR which can be approached from both directions; M2 in which concentrations / macroscopic properties do not change (with time); M3
ij15 6(c)(ii): C; M2 it has a lower (relative) molecular mass (than HBr); M3 ethylamine diffuses faster (than HBr); 3 A ethylamine is less dense A ethylamine is a lighter molecule but I ‘ethylamine is lighter’ I eth
ij16 1(a)(i): C and E;
ij16 1(a)(ii): B;
ij16 1(a)(iii): B;
ij16 1(a)(iv): B;
ij16 1(a)(v): C5H5Cl 5 / CHCl;
ij16 1(b)(i): different number of neutrons / different mass numbers / different numbers of nucleons;
ij16 1(b)(ii): 8; 1
ij16 2(c)(i): breakdown of an ionic compound by the passage of electricity (1 mark for breakdown of a compound by the passage of / using electricity)
ij16 3(a)(i): black / grey-black / grey;
ij16 3(a)(ii): (boiling point) increases down the Group / decreases up the Group;
ij16 3(b)(i): potassium bromide; astatine; 2 1
ij16 3(b)(ii): bromine is less reactive than chlorine / chlorine more reactive than bromine;
ij16 4(c)(i): the higher the values of the boiling range, the greater the number of (carbon) atoms / boiling range is higher, the greater the number of (carbon) atoms / the more atoms, the more energy it takes to b
ij16 4(c)(ii): 52%;
ij16 4(c)(iii): A;
ij16 4(c)(iv): road surfaces / roofing / cattle sprays / synthetic crude oil / battery sealant / treating fences / waterproofing;
ij16 4(d)(i): high temperature / heat;
ij16 4(d)(ii): C5H10; 1
ij16 6(d)(i): (percentage yield) decreases as temperature increases;
ij16 6(d)(ii): 32%;
ij16 6(e)(i): structure of ethanol completed to show all atoms and all bonds;
ij16 6(e)(ii): any suitable use, e.g. fuel / solvent;
ij16 6(e)(iii): 2 (CO2); 3 (H2O); 2 1 1
ij16 7(b)(ii): 3 minutes / 180 s (unit required);
ij16 7(b)(iii): line of steeper gradient than the one shown on the grid and starting at (0, 0); line ends at the same volume as the one shown on the grid but reaches this volume sooner; 2 1
ij16 7(d)(i): (substance containing) 2 or more different atoms bonded / joined together;
ij16 7(d)(ii): named sulfur ore, e.g. zinc sulfide / underground deposits of element;
ij16 7(d)(iii): preservative / bleach / papermaking / wine-making; 1
ij16 8(c)(i): carbon dioxide loses oxygen;
ij16 8(c)(ii): “reaction of an acid with a metal oxide” box ticked;
ij16 8(c)(iii): any 2 from: • climate change / more extreme weather; • desertification; • melting ice caps; • rise in sea levels / increased flooding of low-lying areas; • temperature of atmosphere / oceans increases
ij17 2(a)(i): 8 (mg)
ij17 2(a)(ii): hydrogencarbonate / HCO3 –
ij17 2(a)(iii): nitrate
ij17 2(a)(iv): 12.5 (mg)
ij17 2(d)(ii): platinum / Pt 1
ij17 4(a)(i): hematite / any other ore of iron
ij17 4(a)(ii): from the reaction of carbon dioxide 1 with carbon / coke 1 OR reaction of carbon / coke 1 with insufficient oxygen for compete combustion / idea of oxygen not in excess or not limiting
ij17 4(a)(iii): 2 (Fe) 1 3 (CO2)
ij17 4(a)(iv): iron(III) oxide loses oxygen / iron(III) oxide loses oxygen
ij17 4(a)(v): 160 IF full credit is not awarded, allow 1 mark for (Fe =) 56 and (O =16)
ij17 4(b)(i): hydrogen / H2
ij17 4(b)(ii): gas syringe connected to flask OR this described in words 1 closed apparatus / workable apparatus OR this described in words 1 timer / stop-watch OR this described in words
ij17 5(e)(i): decreases with an increasing number of carbon atoms ORA
ij17 5(e)(ii): any value between 118 and 164 (°C) (exclusive of these values)
ij17 6(a)(i): J it is (very) strong / it is the strongest 1 it is cheap
ij17 6(a)(ii): M because it is the hardest
ij17 6(a)(iii): K because its density is the lowest
ij17 6(b)(i): line at a steeper gradient than W 1 ends up at same mass loss
ij17 6(b)(iii): 1.05 days
ij17 7(d)(i): water 1 air / oxygen
ij17 7(d)(ii): any 2 methods from: greasing / covering with plastic / galvanising / painting / (electro)plating
ij18 1(a)(i): chlorine / Cl 2
ij18 1(a)(ii): ammonia / NH3
ij18 1(a)(iv): carbon monoxide / CO
ij18 1(b)(i): (molecules) made up of two atoms
ij18 1(b)(ii): shared pair of electrons (between two atoms)
ij18 2(a)(i): 72 (%)
ij18 2(a)(ii): hydrogen / H2
ij18 2(b)(i): breathing difficulties / irritates nose / irritates eyes / asthma attacks
ij18 2(b)(ii): 2 (NO2) 1 2 (NaOH)
ij18 2(b)(iii): sodium nitrate
ij18 3(a)(ii): ring around the OH group
ij18 3(a)(iii): (substance which) speeds up a reaction / increases the rate of reaction
ij18 3(a)(iv): idea of very long chains of repeating units / idea of lots of monomers joined together
ij18 3(b)(i): any typical property of an acid e.g. reacts with sodium hydroxide / reacts with hydroxides / reacts with carbonates / reacts with metals / has pH below 7 / colourless / turns litmus red
ij18 3(c)(ii): addition 1 ethene 1 high 1 catalyst 1
ij18 4(c)(i): glowing splint 1 relights
ij18 4(c)(ii): 4 (HCl ) 1 2 (H2O)
ij18 5(a)(i): test tubes of solution covering each electrode
ij18 5(a)(ii): cathode
ij18 5(a)(iv): carbon / platinum
ij18 5(b)(i): 150 (g)
ij18 5(b)(ii): decreases the melting point / melting point is not sharp
ij18 7(a)(i): density of iodine: values between 3.10 and 6.35 (excluding these two values) 1 melting point of At2 values greater than 114 °C but less than 500 °C 1 colour of At2: black / grey-black
ij18 7(a)(ii): it is a gas (at room temperature)
ij18 7(a)(iii): (boiling point) increases down (the group) / (boiling point) decreases up (the group) / increases from chlorine to astatine ORA
ij18 8(d)(i): oxygen (on left) 1 water (on right)
ij18 8(d)(ii): exothermic because energy level of reactants above energy level of products / exothermic because the arrow is going downwards
ij18 8(e)(i): mixture of metals / mixture of metal and non-metal / mixture of metal with another element 1
ij18 8(e)(ii): arrangement: in layers / regular / lattice 1 motion: (only) vibrating
ij19 1(a)(iii): D / Zn / zinc
ij19 1(a)(v): B / NaCl / sodium chloride
ij19 2(a)(i): hematite
ij19 2(a)(ii): iron oxide loses oxygen / oxygen transferred from iron oxide to carbon / carbon takes oxygen away from iron oxide
ij19 2(a)(iii): energy (level) of the products is greater than the energy of the reactants
ij19 2(a)(iv): iron is (relatively) low in the reactivity series
ij19 2(c)(i): 2 (Fe) 3 (Cl2) 2
ij19 2(c)(ii): reversible reaction
ij19 3(a)(i): 0.7 (%)
ij19 3(a)(ii): sodium
ij19 3(a)(iii): any two differences e.g.: • more chlorine / hydrogen / magnesium / oxygen / sodium in oceans than in biosphere ORA • less carbon / silicon / calcium in oceans ORA
ij19 3(b)(i): carbon dioxide
ij19 3(b)(ii): anhydrous copper(II) sulfate / white copper(II) sulfate turns blue OR anhydrous cobalt(II) chloride / blue cobalt(II) chloride turns pink / red 2
ij19 4(c)(i): chlorine sodium iodide 2
ij19 4(c)(ii): chlorine is more reactive than bromine / bromine is less reactive than chlorine
ij19 5(a)(i): circle around COOH group only
ij19 5(b)(ii): last box ticked
ij19 5(d)(i): water / H2O
ij19 5(d)(ii): speeds up reaction / increases the rate of reaction
ij19 5(e)(i): poly(ethene) / polyethene
ij19 5(e)(ii): clothing
ij19 6(b)(i): 2nd box down ticked (decomposition)
ij19 6(b)(ii): 31.7 (g)
ij19 7(b)(i): any value between and including 92–102 s
ij19 7(b)(ii): 34 (cm3)
ij19 7(b)(iii): line steeper than original and starting from 0 line ends up at same final volume AND levels off at or before 90 s 2
ij19 7(b)(iv): increases rate / goes faster
ij19 7(b)(v): decreases rate / goes slower
ij19 8(a)(i): (combustion of) leaded petrol
ij19 8(a)(ii): brain damage (in children) / damage to nervous system
ij19 8(f)(i): methane
ij19 8(f)(ii): global warming / more extreme weather / ice caps melting / sea level rising / glaciers melting / corals die / sea acidified
ij20 1(a)(i): CO2 / carbon dioxide
ij20 1(a)(ii): H2 / hydrogen
ij20 1(a)(iii): N2 / nitrogen
ij20 1(a)(iv): Cu2+ / copper(II) (ions)
ij20 1(a)(v): Cl - / chloride
ij20 2(a)(i): SO42– / sulfate
ij20 2(a)(ii): sulfate
ij20 2(a)(iii): 5.6 (mg)
ij20 2(a)(iv): ammonium nitrate 1
ij20 4(a)(i): decrease down the group / increase up the group
ij20 4(b)(i): lighted splint pops / explodes
ij20 4(b)(ii): C5H10O2
ij20 5(b)(i): inert / unreactive
ij20 5(b)(ii): platinum / graphite
ij20 5(c)(i): chlorine has displaced bromine in sodium bromide / chlorine has taken the place of bromine in sodium bromide
ij20 5(c)(ii): red-brown 1
ij20 6(b)(i): increase in concentration increases rate ORA
ij20 6(b)(ii): larger pieces: decreases (rate) increasing temperature: increases (rate)
ij20 7(c)(i): filtration / filtering
ij20 7(e)(i): H H I I H – C – C – O – H I I H H
ij20 7(e)(ii): steam catalyst
ij21 2(a)(i): Cl – / chloride
ij21 2(a)(ii): Na+ AND NO3–
ij21 2(a)(iii): 1.5 (mg)
ij21 2(c)(i): potassium nitrogen 2
ij21 2(c)(ii): to improve crop yield / to replace nitrogen (or other elements) lost from soil (by being absorbed by plants) / to replace nitrogen (or other elements) absorbed by plants
ij21 2(d)(i): 2 (NaOH) 2 (NH3) 2
ij21 3(a)(i): melting point of Cl any values between –215 and –30 (°C) (inclusive of these values) colour of At: black / grey-black density of F: any values between 0.1 and 1.5 (nm) (inclusive of these values) 3
ij21 3(c)(i): (the number of nucleons) decreases 1
ij21 3(c)(ii): third box down ticked (all isotopes are radioactive) 1
ij21 4(a)(ii): substance which speeds up reaction / substance which increases rate of reaction 1
ij21 4(a)(iii): ethane
ij21 4(b)(i): C8H14O4
ij21 4(b)(iii): universal indicator: turns yellow / orange / red sodium: bubbles / fizzes / sodium decreases in size 2
ij21 4(c)(i): pH 4.2
ij21 4(c)(ii): 23 (cm3)
ij21 4(d)(i): alcohol
ij21 4(d)(ii): addition
ij21 5(a)(i): limestone
ij21 5(a)(ii): methane
ij21 5(c)(ii): measuring cylinder
ij21 5(c)(iii): gas syringe 1
ij21 5(c)(iv): large pieces: rate decreases / (reaction) slower / rate lower lower temperature: rate decreases / (reaction) slower / rate lower 2
ij21 6(b)(i): has a complete outer (electron) shell / has a full outer (electron) shell
ij21 6(b)(ii): lamps / light bulbs
ij21 7(c)(i): separation: far apart / far away (from each other) / distant (from each other) motion: rapid / unrestricted / random 2
ij21 7(c)(ii): glowing splint relights 2
ij21 8(b)(i): giant (structure) covalent (bonding) 2
ij21 8(b)(ii): it is hard 1
ij21 8(b)(iii): graphite
ij22 1(a)(i): He
ij22 1(a)(ii): Li+
ij22 1(a)(iii): H2
ij22 1(a)(iv): CO2
ij22 1(a)(v): O2-
ij22 2(a)(i): PO43- / phosphate
ij22 2(a)(ii): ammonium carbonate
ij22 2(a)(iii): 0.55 (g)
ij22 2(d)(i): group similar 2
ij22 2(d)(ii): 1 mark each for any two of:  carbon monoxide  water  carbon
ij22 3(b)(i): yellow-green 1
ij22 3(b)(ii): the molecule has two atoms
ij22 3(b)(iii): Cl2 2 (NaCl) 2
ij22 3(c)(i): melting point of potassium: values between 42 and 95 (inclusive of these values) atomic radius of sodium: values between 0.160 and 0.230 (inclusive of these values) 2
ij22 3(c)(iii): 1 mark each for any two of:  low(er) density  low(er) melting point  soft(er) 2
ij22 4(c)(ii): reaction which absorbs thermal energy / reaction which absorbs heat
ij22 4(c)(iii): The energy of the reactants is lower than the energy of the products / the energy of the products is higher than the energy of the reactants
ij22 4(c)(iv): 24 (cm3) 1
ij22 5(d)(i): reversible reaction
ij22 5(d)(ii): bleach / manufacture of wood pulp / making paper / food preservative
ij22 5(e)(i): pH 4
ij22 5(e)(ii): (chemical) erosion / corrosion
ij22 6(a)(iv): D 1
ij22 7(b)(iii): inert / unreactive
ij23 2(a)(i): values between –100 °C and +10 °C (inclusive of these values)
ij23 2(a)(ii): values lower than 0.003
ij23 2(b)(i): bromine sodium chloride 2
ij23 2(b)(ii): flame test / put sodium (compound) in (non-luminous) flame (flame colour) yellow 2
ij23 3(a)(i): 1 mark each for any two of:  plastics  phosphates  microbes
ij23 3(a)(ii): contains harmful microbes
ij23 3(b)(i): nickel
ij23 3(b)(ii): sulfate
ij23 3(b)(iii): 0.55 (mg)
ij23 3(c)(i): heat
ij23 3(c)(ii): hydrated
ij23 4(b)(i): 2HBr on left horizontal line AND H2 + Br2 on right horizontal line
ij23 4(b)(ii): the energy of the reactant is lower than the energy of the products / the energy of HBr is lower than the energy of H2 + Br2/ the energy of the products is greater than the energy of the reactants
ij23 4(b)(iii): surroundings
ij23 4(c)(i): H+
ij23 4(c)(ii): salt carbon dioxide water 3
ij23 4(c)(iii): red / pink
ij23 4(d)(iii): conducts electricity / inert 1
ij23 6(a)(i): 40 °C 20 °C 30 °C
ij23 6(a)(ii): takes shorter time / less time taken
ij23 6(a)(iii): takes longer time / more time taken
ij23 7(a)(i): circle around C=C bond
ij23 7(a)(ii): C4H8O
ij23 7(b)(i): CnH2n+1OH
ij23 7(b)(ii): H H │ │ H – C – C – O – H │ │ H H
ij23 8(c)(iii): a substance that dissolves a solute
ij23 8(c)(iv): pH 7
im16 1(a)(i): N / nitrogen;
im16 1(a)(ii): C / carbon / carbon dioxide;
im16 1(a)(iii): Al / aluminium;
im16 1(b)(i): substance containing only one type of atom;
im16 1(b)(ii): number of protons: 20 and 20; number of neutrons: 23 and 28; number of electrons: 20 and 20;
im16 1(b)(iii): 18;
im16 2(b)(i): they are inert / they do not react;
im16 2(b)(ii): any suitable use, e.g. lubricant / pencil leads / brake linings / steelmaking / walls of blast furnace;
im16 3(d)(i): rate increases with increasing temperature; idea that graph is not linear / rate does not increase proportionally / upward curve;
im16 3(d)(ii): 16 ( cm3 hydrogen / min);
im16 4(b)(i): speeds up (rate of) reaction;
im16 4(b)(ii): 3(H2); 2(NH3);
im16 5(a)(iii): magnesium; low density;
im16 5(d)(i): ⇋;
im16 5(d)(ii): add water to anhydrous cobalt sulfate / add water to CoSO4; colour changes (from blue) to red / pink;
im16 6(b)(i): ring around one or more COOH groups;
im16 6(c)(i): carbon dioxide; water;
im16 6(c)(ii): filtration; 1
im16 6(e)(i): 2(C2H5OH) 2(CO2)
im16 6(e)(iii): 180; one row correct = [1], e.g. 12 × 1 = 12 or 6 × 16 = 96
im16 7(d)(i): pH 2; 1
im16 7(d)(ii): water;
im16 7(d)(iii): potassium carbonate;
im17 1(a)(i): oxygen / O2
im17 1(a)(iii): aluminium / Al
im17 2(a)(i): A placed either on the left hand lower tube (or on the one on the right directly opposite this) 1 W placed on both or either of the tubes at the top
im17 2(a)(ii): the slag is above the molten iron / the iron is below the molten slag
im17 2(b)(i): breakdown of a substance / breakdown of a compound 1 using heat / using high temperature
im17 2(b)(ii): CO2
im17 2(b)(iii): calcium oxide reacts with silicon(IV) oxide / sand 1 to form calcium silicate / slag
im17 2(d)(i): graphite / platinum / (pure) iron
im17 2(d)(ii): conducts electricity / inert
im17 2(e)(i): Fe(CO)5 / FeC5O5
im17 2(f)(i): water 1 oxygen / air
im17 2(f)(ii): the lower the pH, the greater the rate / it is faster at a lower pH 1 the higher the temperature, the greater the rate / it is faster at a higher temperature
im17 3(b)(ii): oxygen on left 1 water on right
im17 3(b)(iv): incomplete combustion (of hydrocarbon)
im17 3(b)(v): correct molar mass = 114 8 × 12/96 (in final column) scores [1]
im17 3(c)(i): increases as the number of carbon atoms increases
im17 3(c)(ii): pentane / C5H12 1 20 °C is in between its melting and boiling points / boiling point is above 20 °C and melting point is below 20 °C
im17 3(c)(iii): correct structure of methane showing all four C–H bonds
im17 4(d)(i): neutralises (the acid) / lowers the acidity / raises pH
im17 4(d)(ii): plants cannot grow (well) under acidic conditions 1
im17 5(c)(i): double C=C bond
im17 5(f)(i): on the baseline / on the starting line
im17 6(f)(i): 1.8 g
im17 6(f)(ii): 315 g 1
im17 7(c)(i): atoms with the same number of protons and different numbers of neutrons
im17 7(c)(ii): energy (production) / nuclear power 1
im18 1(a)(i): E / oxygen / O2
im18 1(a)(ii): A / sodium bromide / NaBr
im18 1(a)(iii): E / oxygen / O2
im18 1(a)(iv): C / carbon dioxide / CO2
im18 1(a)(v): A / sodium bromide / NaBr
im18 2(a)(i): 25 (mg)
im18 2(a)(iii): magnesium sulfate
im18 2(b)(i): circle around COOH group
im18 2(b)(ii): C3H6O3
im18 2(c)(i): removal of oxygen (from a compound)
im18 2(c)(ii): 46 If 2 marks not obtained: 1 mark for 1 row all correct e.g. hydrogen 6 × 1 = 6 oxygen 1 × 16 = 16
im18 3(b)(i): density of fluorine: ALLOW: values lower than 1.56 (but not 0 or negative numbers) 1 melting point of chlorine: ALLOW values between –220 and –7 ºC (excluding these two values)
im18 3(b)(ii): lighter because the trend of colour down (the Group) is towards dark(er) colours / lighter because the trend of colour up (the Group) is towards light(er) colours
im18 4(e)(i): one mark each for any two of: • high temperature • catalyst • high pressure max
im18 4(e)(ii): C11H24
im18 5(a)(i): magnesium floats (on the molten magnesium chloride)
im18 5(a)(ii): chlorine
im18 5(a)(iii): to stop the magnesium oxidising / to stop the magnesium reacting with the air / to stop it oxidising / to stop it reacting with the air
im18 5(a)(iv): argon / krypton / xenon
im18 5(b)(i): aluminium 1 has the lowest density / has a low density
im18 5(b)(ii): aluminium 1 has the best (electrical) conductivity
im18 5(b)(iii): cobalt AND nickel
im18 5(d)(i): mixture of metals / mixture of metal and non-metal / mixture of a metal with another element 1
im18 6(a)(i): methane
im18 6(a)(ii): speeds up the reaction / increases the rate of reaction
im18 6(b)(ii): (chemical) erosion (of buildings) / pitting (of buildings) / corrosion (of metalwork) / weathering
im18 6(b)(iii): sulfur dioxide gains oxygen / it gains oxygen
im18 7(b)(i): neutralisation
im18 7(b)(ii): pH 13
im18 7(b)(iii): ammonia
im18 7(b)(iv): 4th box down ticked
im18 8(a)(i): decreases (rate) / slower (rate)
im18 8(a)(ii): decreases (rate) / slower (rate)
im18 8(a)(iii): increases (rate) / faster (rate)
im18 8(b)(i): hematite
im19 2(a)(i): electrons: 92 neutrons: 143 2
im19 2(a)(ii): energy production
im19 3(a)(i): Br– / bromide
im19 3(a)(ii): potassium bromide
im19 3(a)(iii): 11 (mg)
im19 3(a)(iv): e–
im19 3(c)(i): idea of solid turning (directly) to gas
im19 4(b)(i): 54 (cm3)
im19 4(b)(ii): S on any portion of the graph above 2.0 min and below 3.8 min
im19 4(b)(iii): steeper gradient starting at 0-0 ends up at same volume (70 cm3) 2
im19 4(b)(iv): decreases rate / goes slower increases rate / goes faster 2
im19 5(d)(i): from car engines / lightning / high temperature furnaces
im19 5(d)(ii): irritates eyes / nose / mouth / skin / lungs
im19 6(a)(i): chromium is a reactive metal / chromium is high in the reactivity series / chromium is too reactive to be made by reduction with carbon
im19 6(b)(ii): energy of reactants greater than energy of products
im19 6(d)(ii): spoon silvery in colour
im19 6(d)(iii): more corrosion resistant / more attractive appearance
im19 7(a)(i): increases as number of carbon atoms increases / decreases as number of carbon atoms decreases
im19 7(a)(ii): propane
im19 7(b)(ii): carbon dioxide water 2
im20 1(a)(i): potassium manganate(VII)
im20 1(a)(ii): methane
im20 1(a)(iii): potassium iodide / iodide
im20 1(a)(iv): calcium oxide
im20 1(a)(v): ethene
im20 2(b)(i): slag floats on iron / slag is above the iron ORA
im20 2(d)(i): oxygen removed from Fe2O3 / iron oxide loses oxygen
im20 2(d)(ii): 2.8 (g)
im20 4(a)(i): circle round COOH group
im20 4(a)(ii): C5H8O2
im20 5(d)(i): 2 (K) (on left) H2 (on right) 2
im20 5(d)(ii): lilac
im20 6(a)(i): transfers thermal energy to surrounding / transfers heat to surroundings / gives out heat
im20 6(a)(ii): salt
im20 6(a)(iii): combustion
im20 6(a)(iv): (chemical) erosion (of mortar / building materials) / corrodes (iron) 1
im20 6(b)(i): measure volume of gas / measure volume of hydrogen / idea of measuring mass of the reaction mixture reference to (measurement at certain) time(s) suitable collection apparatus related to method sugges
im20 6(b)(ii): large pieces: (rate) decreases / gets slower / slows down increasing temperature: (rate) increases / gets faster 2
im20 8(a)(ii): ionic
im20 8(d)(i): Cl2 (on left) 2 (KCl) (on right) 2
im20 8(d)(ii): chlorine is more reactive than iodine / iodine is less reactive than chlorine 1
im21 2(a)(i): B3O63– / metaborate
im21 2(a)(ii): K+ AND SO42–
im21 2(a)(iii): 80 (mg)
im21 2(a)(iv): sodium chloride
im21 2(a)(v): bromide
im21 2(d)(i): cancer treatment / tracer (e.g. for thyroid function)
im21 2(d)(ii): source of energy / energy production 1
im21 3(a)(ii): increases
im21 3(b)(i): 2,7
im21 3(b)(ii): the number of electrons is one more than the number of protons / it has 9 protons and 10 electrons 1
im21 5(c)(i): C +S on lower line to left AND CS2 on upper line to right 1
im21 5(c)(ii): the product energy level is above the reactant energy level
im21 5(f)(i): (chemical) weathering / ironwork corrodes
im21 5(f)(ii): food preservation / food preservative
im21 6(a)(i): circle around COOH group
im21 6(a)(iii): C5H8O3
im21 6(a)(iv): has a C=C double bond
im21 6(c)(i): idea of breaking down large hydrocarbons to smaller hydrocarbons (using heat)
im21 6(c)(ii): heat / high temperature catalyst 2
im21 7(b)(i): graphite / platinum
im21 7(b)(ii): ‘square’ in middle of diagram labelled anode
im21 7(b)(iii): the sodium floats on top of the sodium chloride
im21 7(e)(i): sodium + hydrogen → sodium hydride 1
im21 7(e)(iii): the iron oxide has lost oxygen
im22 2(a)(i): 1 (%)
im22 2(c)(i): 2 (H2S) 3 (O2) 2
im22 2(c)(ii): sulfur has gained oxygen / hydrogen sulfide has gained oxygen
im22 3(b)(i): mixture of metal with another element
im22 3(b)(ii): (alloy is) hard(er) / (more) resistant to corrosion / strong(er)
im22 3(b)(iii): cutlery / chemical plant / surgical equipment
im22 4(a)(i): sodium nitrate (and) water 2
im22 4(a)(ii): named suitable indicator e.g. methyl orange / litmus correct colour in alkali e.g. blue (for litmus) / yellow (for methyl orange) 2
im22 4(a)(iii): ammonia sodium chloride 2
im22 5(a)(i): G is oxygen H is nitrogen 2
im22 5(a)(ii): volume increases (as temperature increases)
im22 5(a)(iii): they have a full outer shell (of electrons) / they have a complete outer shell (of electrons)
im22 5(a)(iv): arrangement: irregular / random separation: far apart 2
im22 5(b)(i): oxides of nitrogen: breathing difficulties / irritates lungs / irritates eyes / irritates throat / irritates skin / lung problems lead compounds: poisonous / toxic / harms nervous system / harms brain
im22 6(a)(i): boiling point of Na any values between 800 and 1300 (°C) (inclusive of these values) hardness of Li: any value above 0.70 (MPa) up to a maximum of 5.0 (MPa) 2
im22 6(c)(i): carbon / graphite
im22 6(c)(ii): inert / unreactive
im22 7(a)(iv): C4H8O2
im22 7(b)(i): alkenes
im22 7(b)(ii): breakdown of a compound using heat / by heat 2
im22 8(c)(i): 2 (P) 5 (Cl2) 2
im22 8(c)(ii): releases thermal energy / releases heat
im22 8(d)(i): bromine sodium chloride 2
im22 8(d)(iii): bromine is less reactive than chlorine / chlorine more reactive than bromine
im23 2(b)(i): chloride / Cl –
im23 2(b)(ii): sulfate
im23 2(b)(iii): 3.1 (mg)
im23 3(b)(i): car engines / car exhausts / vehicle exhausts
im23 4(c)(i): Mg + Cl2 on line on left AND MgCl2 on line on right
im23 4(c)(ii): the energy of the reactants is greater than the energy of the products / the energy of the products is less than the energy of the reactants
im23 5(b)(ii): anode
im23 5(d)(i): I2
im23 5(d)(ii): displacement
im23 5(d)(iii): (pale) yellow-green
im23 6(a)(i): circle around the OH group
im23 6(a)(ii): C=C bond
im23 6(a)(iii): C4H8O 1
im23 6(a)(iv): 1 mark each for any two of: • (when mixture is heated) water boils off first / water boils off before crotyl alcohol • (because) water has a lower boiling point / crotyl alcohol has a higher boiling p
im23 6(d)(i): covalent
im23 6(d)(ii): H H │ │ H – C – C – H │ │ H H
im23 6(d)(iii): chlorine
im23 6(d)(iv): 2 (O2) CO2 2
im23 7(a)(i): hematite
im23 7(c)(i): (substance) chemically combined with water
im23 7(c)(ii): air / oxygen water 2
im23 7(d)(i): filtration / filter 1
im23 7(d)(ii): 1 mark each for any 2 of: • evaporate to point of crystallisation / evaporate until saturated solution formed • leave to crystalise • filter off crystals / pick out crystals • dry with filter paper
im23 8(a)(i): 27 (cm3)
im23 8(a)(ii): steeper initial gradient starting at 0-0 line levels off at 44 cm3 2
im23 8(b)(i): (rate) decreases / reaction slows down
im23 8(b)(ii): (rate) decreases / reaction slows down
im23 8(c)(i): sodium chloride water 2
im23 8(c)(ii): H+
im23 8(c)(iii): pH 13
im23 8(c)(iv): yellow 1
in15 3(a)(i): vibrate (about fixed position) / vibration;
in15 3(a)(iii): regular / repeated / pattern / framework / ordered / alternating / organised (arrangement of); positive and negative ions / oppositely charged ions / cations and anions / unlike charged ions; 1
in15 3(b)(ii): Li+ + e– → Li / Li+ → Li – e–;
in15 3(b)(iii): 2Br– → Br2 + 2e– / 2Br– – 2e– → Br2 formulae; balancing;
in15 4(a)(i): any three from: • (same) general (molecular) formula; • (consecutive members) differ by CH2; • same functional group; • common (allow similar) methods of preparation; • same / similar chemical propert
in15 4(b)(ii): any correct equation producing an alkane and an alkene adding up to seven carbon atoms in the products; 1
in15 4(c)(i): 150 (cm3);
in15 4(c)(ii): 100 (cm3);
in15 4(c)(iii): This question was discounted.
in15 5(a)(i): proton donor / H+ donor / hydrogen ion donor;
in15 5(b)(i): barium sulphite / barium sulfate(IV) / BaSO3;
in15 5(b)(ii): barium sulfate / BaSO4;
in15 5(b)(iii): Br2 + 2e– → 2Br– / Br2 → 2Br– – 2e–;
in15 5(c)(i): (→) magnesium sulfate + water;
in15 5(c)(ii): (→) zinc sulfate + hydrogen;
in15 5(c)(iii): (→) copper(II) sulfate / copper sulfate + carbon dioxide + water;
in15 5(d)(i): 2NH3 + H2SO4 → (NH4)2SO4 / NH3 + H2SO4 → (NH4)HSO4; 1
in15 5(d)(ii): 2NaOH + H2SO4 → Na2SO4 + 2H2O Na2SO4; rest of equation correct; or H+ + OH– → H2O H2O as the only product on the right hand side; rest of equation correct; or NaOH + H2SO4 → NaHSO4 + H2O NaHSO4; rest
in15 5(d)(iii): Fe + H2SO4 → FeSO4 + H2; FeSO4; rest of equation correct; or Fe + 2H+ → Fe2+ + H2; Fe2+; rest of equation correct; or 2Fe + 3H2SO4 → Fe2(SO4)3 + 3H2; Fe2(SO4)3; rest of equation correct; or 2Fe + 6H+
in15 7(b)(i): repeat experiment using same volume / amount of (same) H2SO4; and same volume / amount of (same) KOH; or (add activated) charcoal / carbon; filter out the charcoal; or mix volumes / amounts of H2SO4 a
in16 1(a)(i): O / oxygen
in16 1(a)(iv): Br / bromine
in16 2(a)(i): phosphate / PO4 3–
in16 2(a)(ii): sulfate
in16 2(a)(iii): 0.5 (g)
in16 2(c)(i): filtration / filter
in16 2(c)(ii): carbohydrate AND protein
in16 2(c)(iii): random / zigzag / go anywhere / irregular 1
in16 2(d)(i): any 2 from: • improve growth of plants • increase protein (in plants) • fertilisers add nitrogen / nitrates / phosphorous / phosphates / potassium • to put back nitrogen / nitrates / phosphorous / pho
in16 2(d)(ii): ammonia is produced / formed (ammonia) is a gas 1
in16 3(b)(ii): values between 125(°C)–145 (ºC) inclusive
in16 3(b)(iii): increases with (increasing) number of carbon atoms
in16 3(c)(i): structure of ethanol showing all of the atoms and all of the bonds OH instead of O─H and rest of structure correct = [1]
in16 4(c)(i): A (volumetric) pipette B burette 1
in16 5(a)(i): endothermic because heating is needed
in16 5(a)(ii): arrow(s) pointing in both directions / ⇌
in16 5(b)(i): C in or just outside the tube at the top left L in or just outside the tube at the bottom right 1
in16 5(b)(ii): to produce a high temperature / for heat(ing)
in16 5(d)(ii): SiO2 / Si6O12
in16 5(e)(i): pH 12
in16 5(e)(ii): H2O
in16 6(a)(iii): any 2 from: • density increases • melting / boiling point decreases • hardness decreases • reactivity increases
in16 6(b)(i): from: colourless / (light) green to: brown 1
in16 6(b)(ii): iodine is more reactive than astatine ORA
in16 6(c)(i): H2 (on left)
in16 6(c)(ii): one pair of bonding electrons between H and Cl 6 non-bonding electrons around Cl and none around H 1
in16 6(c)(iii): lithium chloride water 1 1
in17 1(b)(i): burning fossil fuels / volcanoes / high temperature furnaces / burning named fossil fuel
in17 1(b)(ii): breathing difficulties / irritates nose / irritates eyes / irritates throat
in17 2(c)(iii): it has 8 electrons in its outer shell
in17 2(d)(ii): 98 IF full credit is not awarded, award 1 mark for (S =) 32 , (O = 16) and (H =1)
in17 2(e)(i): bleach / treating wood pulp / preservative
in17 2(e)(ii): pH 2
in17 3(b)(i): condensation (at mouth of tube)
in17 3(c)(i): H2
in17 3(c)(ii): filtration / filter
in17 3(d)(i): structure completed correctly with all of the atoms and all of the bonds IF full credit is not awarded, award 1 mark for OH instead of O–H
in17 3(d)(ii): bubbles OR effervesces / magnesium decreases in size OR magnesium disappears 1
in17 4(d)(i): low density
in17 4(d)(ii): electrolysis
in17 4(f)(ii): drill (bits) / jewellery
in17 5(d)(i): to oxidise impurities / to oxidise named impurities (restricted to phosphorus / sulfur / carbon / silicon)
in17 5(d)(ii): potassium oxide 1 it is the oxide of a metal / metal oxides are basic
in17 5(f)(i): car bodies / bridges / railings 1
in17 5(f)(ii): cutlery / chemical plant
in17 6(c)(i): correct structure of ethane showing all of the atoms and all of the bonds
in17 6(c)(ii): 3 (H2)
in17 6(c)(iii): takes in heat (from surroundings) / absorbs heat / absorbs thermal energy
in17 6(e)(i): (boiling point) increases
in17 6(e)(ii): any value between –8 and –80 (°C) inclusive of these values
in18 2(a)(i): One mark each for any 2 of: • concentration of sodium in squid / nerves lower ORA • concentration of potassium in squid / nerves higher ORA • concentration of hydrogencarbonate in squid / nerves lower
in18 2(a)(ii): 3.9 (g)
in18 3(a)(ii): harder / stronger / more resistant to corrosion
in18 3(b)(ii): nitrogen dioxide / NO2 lightning / high temperature furnaces 2
in18 3(d)(ii): add water
in18 4(a)(i): C=C (double bond)
in18 4(a)(ii): orange / red-brown to colourless / decolourised 2
in18 4(a)(iii): structure of COOH group showing all atoms and all bonds
in18 4(a)(iv): turns it red / pink
in18 4(b)(i): One mark each for any two of: • not much decrease / gradual decrease in pH at first • sudden decrease in pH as more acid added • not much decrease / gradual decrease in pH when acid in excess
in18 4(b)(ii): any value between pH 12.65 and 12.75 (inclusive)
in18 4(b)(iii): 14 cm3
in18 5(d)(iii): bubbles / strong smell (of chlorine)
in18 7(b)(i): any value between 5.0 and 5.5 min (inclusive)
in18 7(b)(ii): 96 cm3
in18 7(d)(i): hematite / any other ore of iron e.g. siderite
in18 7(d)(ii): air monoxide decomposes slag 4
in18 8(a)(ii): (chlorine is a) gas (at room temperature)
in18 8(b)(i): to kill bacteria
in18 8(b)(ii): any suitable use e.g. coolant / solvent / chemical use in named reaction e.g. hydration of alkenes
in19 1(a)(i): carbon monoxide
in19 1(a)(ii): propene
in19 1(a)(iii): carbon dioxide
in19 1(a)(iv): chlorine
in19 1(a)(v): sulfur dioxide
in19 1(b)(i): goes from solid to gas directly / without liquid (being formed) 2
in19 1(b)(ii): solid: particles (only) vibrating particles close together / particles touching gas: particles moving rapidly / particles moving randomly particles far apart 4
in19 2(a)(i): 1.5 (%)
in19 2(a)(ii): 1 pair of electrons between each O and H 4 non-bonding electrons on oxygen and none on the hydrogens 2
in19 2(a)(iii): anhydrous copper(II) sulfate turns blue IF: 2 marks not scored 1 mark for anhydrous copper sulfate or copper sulfate turns blue OR anhydrous cobalt(II) chloride turns pink / red IF: 2 marks not scored
in19 2(b)(i): 2 (CH4) 4 (H2) 2
in19 2(b)(ii): butane
in19 2(d)(i): circle round the COOH group
in19 4(e)(i): food preservative / manufacture of wood pulp
in19 4(e)(ii): magnesium sulfate hydrogen 2
in19 5(a)(i): melting point of lithium: values between 110 ºC and 210 ºC (inclusive) atomic radius of potassium: values between 190 pm and 240 pm (inclusive) 2
in19 5(a)(ii): decreases (down the group)
in19 5(b)(i): 4 (Li) 2 (Li2O) 2
in19 5(b)(ii): basic (oxide) AND Li is a metal
in19 5(b)(iii): electron
in19 5(b)(iv): 36 if 2 marks not scored: 1 mark for C = 2 × 12 OR 24
in19 6(d)(i): speeds up rate of reaction / makes reaction faster
in19 6(d)(ii): any suitable source, e.g. from car engines / lightning / high temperature furnaces
in19 6(d)(iii): irritates eyes / nose / mouth / skin / airways / lungs
in19 8(b)(ii): oxidation
in20 1(a)(i): H / H2 / hydrogen
in20 1(a)(ii): Cl / chlorine / Cl 2
in20 1(a)(iii): Al / aluminium / Al 3+
in20 1(a)(v): Al /aluminium
in20 1(b)(i): 2nd box down ticked (they are atoms with the same number of protons …)
in20 1(b)(ii): protons = 16 neutrons = 17 2
in20 2(a)(i): ozone
in20 2(a)(ii): 26.5 (ng)
in20 2(b)(i): oxygen is not in excess / oxygen is limiting / there is excess carbon / there is excess fuel
in20 2(b)(ii): poisonous / toxic / kills you
in20 2(c)(i): increases rate of reaction / speeds up a reaction
in20 2(c)(ii): decomposition of plants / waste gases from digestion of animals / natural gas
in20 2(d)(i): 2 (CO) (on left) 2 (CO2) (on right) 2
in20 2(d)(ii): reactants on left top line and products on bottom right line
in20 2(d)(iii): the reactants have more energy / the product(s) have less energy
in20 2(e)(ii): pH 6
in20 4(a)(i): circle round C = C group
in20 4(a)(ii): C4H6O2
in20 4(a)(iii): 86 If two marks not scored, 1 mark for 6 × 1 = 6 / 2 × 16 = 32 2
in20 4(c)(ii): breakdown of a compound by heating / by high temperature 2
in20 5(d)(ii): fractional distillation 2
in20 7(a)(i): idea of greater values for volume than mass lost / in method 2 mass of flask decreases only slightly / I method 2 idea of small decreases in mass involved / in method 2 mass loss too small (to measure
in20 7(a)(ii): carbon dioxide goes out of the flask / carbon dioxide escapes / gas escapes
in20 7(b)(i): decreases (as time increases)
in20 7(b)(ii): 60 s
in20 7(b)(iii): line starts at 0, 0 and steeper gradient line levels out at 48 cm3 carbon dioxide and before the line already on the grid 2
in20 7(b)(iv): temperature: increases / gets faster concentration: decreases / gets slower 2
in20 8(a)(i): 1st box down ticked (relatively soft metal) 4th box down ticked (lower density) 2
in20 8(a)(ii): R: freezing S: boiling / evaporation 2
in20 8(e)(i): add water 1
in20 8(e)(ii): hydrated 1
in21 1(a)(i): LiCl
in21 1(a)(ii): MgCl2
in21 1(a)(iii): CO2
in21 1(a)(iv): SO2
in21 1(a)(v): O2
in21 2(a)(i): Fe3+
in21 2(a)(ii): calcium nitrate
in21 2(a)(iii): 5.5 (mg)
in21 2(c)(i): OH alcohol group circled 1
in21 2(c)(ii): C3H7O3N
in21 2(c)(iii): 88 if two marks nor scored, 1 mark for 8 × 1 = 8 OR 2 × 16 = 32 2
in21 3(b)(i): hematite
in21 3(b)(ii): 3 (Fe) 4 (CO2) 2
in21 3(b)(iii): Fe3O4 loses oxygen / it loses oxygen
in21 3(d)(i): mixture of metal with another substance
in21 3(d)(iii): electrons: 23 neutrons: 28 protons: 23 3
in21 3(d)(iv): 1 mark each for any two of: • lustrous / shiny • conducts heat • ductile 2
in21 4(a)(i): boiling point of I: values from 120 to 330 °C (inclusive of these values) density of Br: values from 1.6 to 4.9 (inclusive of these values) 2
in21 4(a)(ii): increases
in21 4(b)(i): 2.8.7
in21 4(b)(ii): it has one more electron than protons / it has 35 protons and 36 electrons 1
in21 5(d)(i): breakdown of (large / long-chain) hydrocarbons by heat / by heating 2
in21 5(d)(ii): ethanol
in21 5(d)(iii): polymer
in21 6(c)(i): incomplete combustion / combustion in limited air / combustion in limited oxygen
in21 6(c)(ii): poisonous / toxic 1
in21 7(a)(i): melting / fusion
in21 7(a)(ii): separation: solid: particles close to each other liquid: particles close to each other motion: solid: vibrating liquid: sliding over each other / limited motion / restricted motion 4
in21 7(f)(i): natural gas
in22 1(c)(i): combustion in limited oxygen / combustion in limited air / not enough air to burn completely
in22 1(c)(ii): poisonous / toxic
in22 2(a)(i): 0.9 (%)
in22 2(a)(ii): oxygen
in22 2(c)(i): to oxidise the carbon / to oxidise the coke / to make carbon dioxide
in22 2(c)(ii): 2 (CO)
in22 2(c)(iii): loss of oxygen (from a compound)
in22 2(c)(iv): 20 (g)
in22 2(d)(i): calcium oxide oxygen 2
in22 2(d)(ii): mixture of metal(s) and other elements
in22 3(b)(i): refinery gases / kerosene / fuel oil
in22 3(b)(ii): boiling point
in22 3(b)(iii): X drawn next to bottom right-hand arrow
in22 3(c)(i): uranium
in22 3(c)(ii): testing for leaks in pipes / measuring paper thickness 1
in22 4(a)(i): boiling point of sodium: values between 770 and 1300 (inclusive of these values) hardness of rubidium: values between 0.1 and 0.35 (inclusive of these values) 2
in22 4(b)(i): 2 (Na) 2 (Na2O) 2
in22 4(b)(ii): lighted splint pops / explosion 2
in22 5(b)(i): reversible reaction
in22 5(b)(ii): 78 (%)
in22 5(d)(i): sulfur dioxide
in22 5(d)(ii): chemical weathering / erosion / pitting of surface
in22 6(b)(i): very small large small
in22 6(b)(ii): takes longer / time increases
in22 6(c)(i): from red / pink to yellow 2
in22 6(c)(ii): pH 14
in22 6(d)(ii): increases reaction rate / makes the reaction go faster / speeds up the reaction
in22 7(a)(i): circle around COOH group
in22 7(a)(ii): C4H6O2
in22 7(a)(iii): regular / ordered 1
in22 7(b)(i): H H │ │ H – C – C – O – H │ │ H H 1
in22 7(b)(ii): (reaction of) ethene with steam 2
in22 7(c)(i): monomer(s)
in22 7(c)(ii): protein
in22 7(c)(iii): block drains / litter / (fills) landfill (sites) / poisonous fumes given off when burned
in22 8(a)(ii): electrical wiring
in22 8(b)(ii): spoon gets brown / red-brown / pink pure copper rod gets smaller 2
in23 2(b)(i): X in lowest section of the column / X in the tube where bitumen collects
in23 2(b)(ii): diesel (oil) / gas oil
in23 2(b)(iii): refinery gas
in23 2(b)(iv): chemical feedstock / making chemicals 1
in23 3(a)(i): hydrocarbons
in23 3(a)(ii): sulfur dioxide
in23 3(a)(iii): 4.4 (ng)
in23 3(b)(i): car engines / vehicle engines / lightning
in23 3(b)(iii): pH 7
in23 3(d)(i): 2(SO2) O2 2
in23 3(d)(ii): reversible (reaction)
in23 5(a)(i): values between 20 and 62 °C (inclusive of these values)
in23 5(a)(ii): values between 24 and 55 cm3 / mol (inclusive of these values)
in23 5(a)(iii): bubbles form rapidly
in23 5(b)(i): 21 (%)
in23 5(b)(ii): the carbon dioxide is reduced and the carbon is oxidised
in23 5(b)(iii): reaction that transfers thermal energy / reaction that gives out heat to the surroundings 2
in23 5(c)(i): thermal decomposition
in23 5(c)(ii): slag / calcium silicate
in23 6(a)(i): 42 (cm3)
in23 6(a)(ii): shallower gradient with line starting at 0,0 line levels off at 46 cm3 AND not hitting original line before it reached 46 cm3 2
in23 6(b)(i): (rate) decreases / rate slower / more slowly
in23 6(b)(ii): (rate) decreases / rate slower / more slowly
in23 6(c)(i): soluble base
in23 6(c)(ii): OH−
in23 6(c)(iii): yellow
in23 6(c)(iv): ammonium chloride 1
in23 7(b)(i): alcohol
in23 7(b)(ii): one mark each for any two of: • 25–45 °C (inclusive of these values) • yeast • absence of oxygen / anaerobic
in23 7(c)(i): circle around C=C bond
in23 7(c)(ii): orange
in23 7(c)(iii): C4H6O2
in23 8(c)(i): decomposition of an ionic compound / breaking down of an ionic compound by an electric current 2
in23 8(e)(i): covalent
in23 8(e)(ii): giant structure AND hard / strong bonds AND hard / many bonds AND hard 1
in24 1(a)(i): Zn 1 1a(ii) Ca
in24 1(a)(iv): Al
in24 1(a)(v): Fe
in24 2(a)(i): 21 (%)
in24 2(a)(iii): poly(ethene)
in24 2(a)(iv): monomer(s)
in24 2(b)(ii): 4th box down ticked (strong electrostatic attraction between cations and anions) 1
in24 3(c)(i): tin
in24 3(c)(ii): sulfate
in24 3(c)(iii): 0.8 (mg)
in24 4(a)(i): COOH group circled
in24 4(a)(ii): C3H7NO3
in24 4(c)(i): alcohol(s) 1
in24 4(c)(ii): CnH2n+1OH
in24 4(c)(iii): Increases
in24 4(d)(i): substances required: • ethene • steam / water • conditions: one mark each for any two of: • 300 °C • 6000 kPa / 60 atm (pressure) • acid catalyst 4
in24 4(d)(ii): H H │ │ H – C – C – O – H │ │ H H
in24 4(d)(iii): carbon monoxide
in24 5(a)(i): values between 116 °C and 335 °C (inclusive of these values)
in24 5(a)(ii): values less than 22.7 (cm3 / mol) but not below 1.0
in24 5(b)(i): iodine sodium chloride 2
in24 5(b)(ii): bromine is less reactive than chlorine / chlorine is more reactive than bromine / chlorine is higher in the electrochemical series than bromine
in24 6(b)(i): number of neutrons in Ca = 28 number of electrons in Cu2+= 27 number of protons in Ca = 20 AND number of protons in Cu2+ = 29 3
in24 6(b)(ii): 2,8,8,2
in24 7(a)(i): (l)
in24 7(a)(ii): filtration
in24 7(a)(iii): one mark each for any two of: • heat to point of crystallisation / heat to form saturated solution • filter off crystals / pick out crystals • dry with filter paper
in24 7(c)(i): thermal energy is released (in the reaction) / (reaction that) transfers thermal energy / (reaction that) gives out heat
in24 7(c)(ii): ZnO +HCl on the line on the left AND ZnCl2 and H2O on the line on the right 1
in24 7(c)(iii): the energy (level) of the reactants is higher than the energy (level) of the products / the energy (level) of the ethene is higher than the energy (level) of the poly(ethene) / the energy of the produ
in24 8(a)(i): 0.8 1.6 0.4
in24 8(a)(ii): longer time / increases time / more time
in24 8(a)(iii): longer time / increases time / more time
j18 1(a)(i): ammonia / NH3
j18 1(a)(iv): carbon dioxide / CO2
j18 1(b)(ii): (old) light bulbs / welding / to protect reactive metals from oxidation / lasers
j18 2(a)(i): 15.5(%)
j18 2(a)(ii): hydrogen / H2
j18 2(a)(iii): nitrogen AND oxygen
j18 2(a)(iv): NO2
j18 2(a)(v): the air / the atmosphere
j18 2(b)(ii): poisonous / toxic
j18 2(b)(iii): 5 (CO2) 1 6 (H2O)
j18 3(b)(i): (substance which) speeds up a reaction / substance which increases the rate of reaction
j18 3(c)(i): C=C bond
j18 3(c)(ii): orange / red-brown / brown 1 to colourless
j18 4(e)(ii): Fe2Cl 6
j18 7(a)(i): atomic radius of Rb: any value between 228 and 264 (inclusive of these values) 1 relative thermal conductivity of K: any value between 3.8 and 1.7 (inclusive of these values)
j18 7(a)(ii): decreases down (the Group) / increases up (the Group) / decreases from sodium to caesium ORA
j18 7(a)(iii): bursts into flame / extremely rapid bubbling / explodes
j19 1(a)(i): B / diamond D / nitrogen / N2 2
j19 1(a)(ii): D / nitrogen / N2
j19 1(a)(iii): C / lithium chloride / LiCl
j19 1(a)(iv): C / lithium chloride / LiCl
j19 1(a)(v): B / diamond
j19 2(d)(i): thermal decomposition
j19 2(d)(ii): basic oxide calcium is a metal (oxide) 2
j19 3(a)(i): 5.0%
j19 3(a)(ii): oxygen
j19 3(a)(iii): any two from: • more hydrogen in Universe (or reverse argument) • more helium in Universe (or reverse argument) • more oxygen on Earth (or reverse argument) • more magnesium on Earth (or reverse argum
j19 3(c)(i): has complete outer (electron) shell / has full outer (electron) shell / outer shell cannot gain or lose electron(s)
j19 3(c)(ii): lamps / inert atmosphere (in metal extraction) 1
j19 4(c)(i): bromine potassium iodide 2
j19 4(c)(ii): chlorine more reactive than iodine / iodine less reactive than chlorine
j19 4(d)(i): 2 (Na2S2O3) 2 (NaI) 2
j19 4(d)(ii): the energy of the reactants is more than the energy of the products / the energy of the products is less than the energy of the reactants / the reactants lose energy when they form products
j19 5(a)(i): methane
j19 5(a)(iii): with methane (aqueous) bromine remains orange with ethene (aqueous) bromine decolourised 2
j19 5(b)(ii): monomers
j19 5(b)(iii): cannot be decomposed by organisms / cannot be broken down by bacteria / cannot be broken down by fungi
j19 5(b)(iv): gets stuck in gullets of birds / gets stuck in gullets of animals / blocks drains
j19 6(b)(i): reversible reaction
j19 6(b)(ii): heat / warm
j19 6(e)(i): mixture of metal and other elements
j19 6(e)(ii): (alloy) more resistant to wear / stronger / harder / more resistant to corrosion ORA for copper 1
j19 7(b)(i): gas released / gas escapes / gas lost
j19 7(b)(ii): 0.7 (g)
j19 7(b)(iii): line steeper than original and starting from 0 and 200.0 g line ends up at same final mass AND levels off at or before 104 s 2
j19 7(b)(iv): 0.22 (g)
j19 7(b)(v): large pieces → 0.005 small pieces → 0.030 powder → 0.100
j19 8(a)(i): burning fossil fuels / volcanoes / heating (sulfide) ores
j19 8(a)(ii): substance which speeds up a reaction / substance which increases the rate of reaction
j19 8(a)(iii): pH4
j20 1(a)(i): CO2 / carbon dioxide
j20 1(a)(ii): H2 / hydrogen
j20 1(a)(iii): N2 / nitrogen
j20 1(a)(iv): Cu2+ / copper(II) (ions)
j20 1(a)(v): Cl - / chloride
j20 2(a)(i): SO42– / sulfate
j20 2(a)(ii): sulfate
j20 2(a)(iii): 5.6 (mg)
j20 2(a)(iv): ammonium nitrate 1
j20 4(a)(i): decrease down the group / increase up the group
j20 4(b)(i): lighted splint pops / explodes
j20 4(b)(ii): C5H10O2
j20 5(b)(i): inert / unreactive
j20 5(b)(ii): platinum / graphite
j20 5(c)(i): chlorine has displaced bromine in sodium bromide / chlorine has taken the place of bromine in sodium bromide
j20 5(c)(ii): red-brown 1
j20 6(b)(i): increase in concentration increases rate ORA
j20 6(b)(ii): larger pieces: decreases (rate) increasing temperature: increases (rate)
j20 7(c)(i): filtration / filtering
j20 7(e)(i): H H I I H – C – C – O – H I I H H
j20 7(e)(ii): steam catalyst
j21 2(a)(i): Cl – / chloride
j21 2(a)(ii): NH4+ AND SO42-
j21 2(a)(iii): 24 (mg)
j21 3(a)(i): boiling point of Rb: any values between 675 and 755 (°C) (inclusive of these values) atomic radius of K: any values between 0.195 and 0.245 (nm) (inclusive of these values) 2
j21 3(a)(ii): decreases 1
j21 3(b)(i): number of protons in the nucleus of an atom / number of positive charges in the nucleus of an atom
j21 3(b)(ii): any suitable, e.g. detecting leaks in pipes / measuring thickness of paper / energy production
j21 3(c)(i): 2 (Fe) 3 (NaOH) 2
j21 3(c)(ii): iron(III) oxide loses oxygen / it loses oxygen
j21 4(a)(i): OH alcohol group circled
j21 4(a)(ii): C4H6O5
j21 4(c)(i): large molecules / long chain molecules / macromolecules built up from (many) small units / made from monomers 2
j21 4(c)(ii): poly(ethene)
j21 4(e)(i): pH 13
j21 4(e)(ii): 18 (cm3)
j21 5(a)(i): breakdown of substance / idea of one substance forming two or more substances using heat / on heating 2
j21 5(b)(i): gas syringe / upturned measuring cylinder dipping into container apparatus is workable and airtight 2
j21 5(c)(ii): alkane(s)
j21 5(c)(iii): 1 mark each for any 2 of: • carbon monoxide • carbon • water
j21 6(b)(i): nitrogen oxygen 2
j21 6(b)(ii): large(r) particles cannot get through (the small gaps in) the filter / large(r) particles get trapped in the filter / large(r) particles too big to get through (filter) water passes through 2
j21 6(b)(iii): to kill bacteria / to kill micro-organisms
j21 7(a)(ii): platinum 1
j22 1(a)(i): CO2
j22 1(a)(ii): K+
j22 1(a)(iii): O2
j22 1(a)(v): Br-
j22 2(a)(i): Mg2+ / magnesium
j22 2(a)(ii): magnesium sulfate
j22 2(a)(iii): 6.4 (g)
j22 2(d)(i): H H │ │ H─C─C─O─H │ │ H H
j22 2(d)(ii): carbon dioxide water 2
j22 2(d)(iii): fuel / solvent
j22 3(c)(i): melting point of sodium: values between 65 and 178 (inclusive of these values) hardness of potassium: values between 0.3 and 0.6 (inclusive of these values) 2
j22 3(d)(i): bromine displaces iodine from potassium iodide / bromine replaces iodide in potassium iodide
j22 3(d)(ii): brown 1
j22 4(d)(i): exothermic
j22 4(d)(ii): reactants on top left horizontal line and products on bottom left horizontal line
j22 5(c)(i): bauxite
j22 5(c)(ii): aluminium is too reactive / aluminium is above carbon in the reactivity series
j22 6(a)(i): D and E
j22 6(a)(iii): C 1
j22 7(a)(ii): density is low(er) / melting point is low(er) / soft
j23 2(a)(i): values between 115 °C and 335 °C (inclusive of these values)
j23 2(a)(ii): values between 4.95 and 15.0 (inclusive of these values)
j23 2(b)(i): iodine potassium bromide 2
j23 2(b)(ii): bromine is more reactive than iodine / iodine is less reactive than bromine
j23 3(a)(i): 1 mark each for any two of:  plastics  sewage  microbes
j23 3(a)(ii): deoxygenation of water / remove oxygen from water
j23 3(b)(i): potassium
j23 3(b)(ii): nitrate
j23 3(b)(iii): 0.4 (mg)
j23 3(c)(i): add water
j23 3(c)(ii): anhydrous
j23 4(c)(i): reaction that transfers thermal energy / reaction that gives out heat to the surroundings 2
j23 4(c)(ii): Cl2 + H2 on left horizontal line AND 2HCl on right horizontal line
j23 4(c)(iii): the energy of the reactants is greater than the energy of the product / the energy of Cl2 + H2 is greater than the energy of HCl / the energy of the products is less than the energy of the reactants
j23 4(e)(i): sodium chloride water 2
j23 4(e)(ii): OH-
j23 5(a)(i): hematite
j23 5(a)(ii): carbon carbon dioxide 2
j23 6(a)(i): medium small large
j23 6(a)(ii): takes shorter time / less time taken
j23 6(a)(iii): takes longer time / more time taken
j23 7(a)(i): circle around OH group
j23 7(a)(ii): C5H6O5
j23 7(a)(iii): has a C=C bond / has a carbon – carbon double bond 1
j23 7(b)(ii): aqueous bromine turns colourless / decolourises 2
j23 7(c)(i): catalyst high temperature 2
j23 7(c)(ii): C8H18
j23 8(b)(ii): CnH2n+2
j23 8(b)(iii): decomposition of vegetation / waste gases from digestion in animals
j23 8(b)(v): carbon monoxide
j23 8(c)(i): pH 4
j24 2(a)(i): magnesium
j24 2(a)(ii): hydrogen phosphate
j24 3(a)(i): anode correctly labelled
j24 3(a)(ii): graphite
j24 3(d)(i): H+
j24 3(d)(ii): hydrogen
j24 3(d)(iii): blue to colourless 2
j24 3(d)(iv): universal (indicator) 1
j24 4(a)(i): H H │ │ C = C │ │ H H
j24 4(a)(ii): 1 mark each for any 2 of:  carbon monoxide  carbon  water
j24 4(b)(i): spot or cross on the chromatography paper vertically below the 4 spots already on the paper solvent level below the dot or cross and chromatography paper dipping into solvent 2
j24 4(b)(ii): 1 mark each for any 2 of:  does not have a fixed composition  the properties of a mixture are those of the substances present  can be separated (into its components by physical means)  (components
j24 5(b)(i): acid rain 1
j24 5(b)(ii): SO2 2 (MgO) 2
j24 6(b)(i): X at beginning of graph line
j24 6(b)(ii): 1.
j24 6(c)(i): pressure: (rate) decreases / slower (reaction) catalyst: (rate) increases / faster (reaction) 2
j24 6(d)(i): pH 1
j24 6(e)(ii): catalytic converter
j24 7(b)(ii): 4th box down ticked (hydrated iron(III) oxide)
j24 8(a)(i): increases with the number of carbon atoms / increases down the series
j24 8(a)(ii): CnH2n+1COOH
j24 8(b)(i): water carbon dioxide 2
j24 8(b)(ii): CH3COONa
j24 8(c)(ii): covalent
j24 8(c)(iii): combustion substitution with chlorine 2
n21 1(a)(i): CH4
n21 1(a)(ii): Cl 2
n21 1(a)(iii): Cl 2
n21 1(a)(iv): NaCl
n21 1(a)(v): CH4
n21 2(a)(i): SiO32-
n21 2(a)(ii): sodium nitrate
n21 2(a)(iii): 1.10 / 1.1 (mg)
n21 2(c)(i): 3 1
n21 2(c)(ii): 192 if two marks not scored, 1 mark for 8 × 1 = 8 OR 7 × 16 = 112 2
n21 3(b)(i): 3 (CO) 2 (Fe) 2
n21 3(b)(ii): loss of oxygen (from a compound)
n21 3(d)(i): cutlery / chemical plant
n21 3(d)(ii): reduced corrosion / harder / stronger
n21 4(a)(i): melting point of K: values from 41 to 96 °C (inclusive of these values) density of Fr: values from 1.9 to 4.0 (inclusive of these values) 2
n21 4(a)(ii): slow bubbling
n21 4(b)(i): 2.8.1
n21 4(b)(ii): it has one more proton than electrons / it has 19 protons and 18 electrons 1
n21 4(c)(i): 2 (NaOH) H2 2
n21 4(c)(ii): pH 14
n21 5(d)(i): high temperature catalyst 2
n21 5(d)(ii): hydrogen
n21 5(f)(i): large molecules / long molecules made from small units / made from monomers 2
n21 5(f)(ii): clothing, ropes
n21 5(f)(iii): filling landfill sites / gets stuck in animals digestive system / animals get stuck in the plastic / blocks drains / stops light getting to plants under water 1
n21 6(b)(i): iodine
n21 6(b)(ii): potassium bromide iodine 2
n21 6(b)(iii): chlorine more reactive than bromine / bromine less reactive than chlorine
n21 7(c)(i): irritates nose / irritates throat / irritates lungs / irritates eyes
n21 7(c)(ii): oxides of nitrogen / nitrogen dioxide
n22 2(a)(i): 3.5 (%)
n22 2(a)(ii): oxygen
n22 2(a)(iii): one mark each for any 2 of: • more aluminium in Earth / less aluminium on moon • less iron in Earth / more iron on moon • more oxygen in Earth / less oxygen on moon • more silicon in Earth / less sili
n22 2(c)(i): 3 (Fe) 2 (O2) 2
n22 2(c)(iii): air reduced dioxide slag 4
n22 2(d)(i): oxidises the carbon / converts it to carbon dioxide
n22 2(d)(ii): basic oxide
n22 4(a)(i): density of iodine: values between 3.2 and 6.2 (inclusive of these values) boiling point of astatine: values between 305 and 1000 (inclusive of these values) 2
n22 4(b)(i): 2 (H2O) 2 (HBr) 2
n22 4(b)(ii): loss of oxygen
n22 5(b)(i): vehicle engines / high temperature furnaces / lightning
n22 5(b)(ii): breathing difficulties / asthma
n22 5(c)(i): phosphorus
n22 5(c)(ii): to increase crop growth / to replace elements taken from soil by previous crops
n22 6(c)(ii): pH 2
n22 6(d)(i): neutralisation
n22 6(d)(ii): step 3 filter (the mixture) step 6 dry crystals on filter paper / dry crystals in drying oven 2
n22 6(e)(i): 40 60 20
n22 6(e)(ii): time taken is less / shorter
n22 7(a)(ii): C5H10O2
n22 7(b)(i): (substance that) speeds up a reaction / (substance that) increases the rate of a reaction / (substance that) makes the reaction go faster
n22 7(b)(ii): fermentation 1
n22 7(c)(i): H H │ │ C = C │ │ H H
n22 7(c)(ii): far apart
n22 7(c)(iii): to produce more needed products / to produce products in greater demand
n22 7(c)(iv): poly(ethene)
n22 8(b)(i): cathode
n22 8(b)(ii): prevents corrosion / makes object (surface) hard(er)
n23 2(b)(i): X in lowest section of the column / X in the tube where bitumen collects
n23 2(b)(ii): naphtha
n23 2(b)(iii): bitumen
n23 2(b)(iv): fuel for ships / fuel for home heating
n23 3(a)(i): sulfur dioxide
n23 3(a)(ii): carbon monoxide
n23 3(a)(iii): 7.0 1
n23 3(b)(i): (lung) cancer / respiratory problems
n23 3(b)(ii): combustion when oxygen / air is limiting
n23 3(c)(i): pH 5
n23 3(c)(ii): catalytic converter
n23 3(c)(iii): aqueous solution: sodium hydroxide / potassium hydroxide metal: aluminium 2
n23 3(d)(i): 2 (NO2) O2 2
n23 3(d)(ii): reversible (reaction)
n23 5(a)(i): values between 770 and 1330 °C (inclusive of these values)
n23 5(a)(ii): values between 46 and 150 cm3 / mol (inclusive of these values)
n23 5(a)(iii): bubbles form slowly
n23 5(b)(i): iron(III) oxide / Fe2O3 / it has lost oxygen
n23 5(b)(iii): calcium oxide carbon dioxide 2
n23 5(c)(i): C 1
n23 5(c)(ii): hard(er) / (more) resistant to corrosion
n23 6(a)(i): 33 (cm3)
n23 6(a)(ii): steeper gradient with line starting at 0,0 line levels off at 43 cm3 AND not hitting original line before it’s reached 43 cm3 2
n23 6(b)(i): rate faster / reaction speeds up / increase
n23 6(b)(ii): rate slower / more slowly / decrease
n23 6(c)(i): lithium chloride water 2
n23 6(c)(ii): neutralisation
n23 6(c)(iii): blue
n23 7(a)(i): circle around a COOH group
n23 7(a)(ii): C4H4O4
n23 7(a)(iii): orange colourless 2
n23 7(d)(i): solvent / fuel
n23 7(d)(ii): CnH2n+1OH
n23 7(d)(iii): one mark each for any two of: • 300 °C • 6000 kPa / 60 atm • (acid) catalyst
n23 8(c)(i): protons: 30 electrons: 37 2
n23 8(c)(ii): cations 1
n23 8(e)(i): inert / unreactive
n23 8(e)(ii): giant covalent
n23 8(e)(iii): lubricant 1
n24 1(a)(ii): Al
n24 1(a)(iv): Ba
n24 1(a)(v): Al
n24 1(a)(vi): Au
n24 1(b)(i): has (only) one atom
n24 1(b)(ii): outer electron shell is complete / outer electron shell is full
n24 2(a)(i): low melting point / low boiling point poor electrical conductivity 2
n24 2(a)(ii): electrons
n24 2(c)(i): cutting (tools)
n24 2(c)(ii): 2nd box down ticked (giant covalent) 1
n24 3(c)(i): hydrogencarbonate
n24 3(c)(ii): nitrate
n24 3(c)(iii): 0.4 (mg)
n24 3(d)(i): to remove solids
n24 3(d)(i): to kill (harmful) microbes
n24 4(a)(i): O-H group circled
n24 4(a)(ii): C4H6O5
n24 4(d)(i): alkene(s)
n24 4(d)(ii): CnH2n
n24 4(d)(iii): increases
n24 4(e)(i): one mark each for any three of: • larger alkane molecules • using high temperatures • using catalyst • smaller molecules (also produced)
n24 4(e)(ii): to produce more hydrocarbons / fractions that are in demand e.g. gasoline or diesel / to produce more hydrocarbons / fractions that are in short supply / to produce hydrogen 1
n24 5(a)(i): values between 116 °C and 335 °C (inclusive of these values)
n24 5(a)(ii): values between 0.05 and 1.55 g / cm3 (inclusive of these values)
n24 5(b)(i): bromine lithium chloride 2
n24 5(b)(ii): iodine is less reactive than bromine / bromine is more reactive than iodine / bromine is higher in the electrochemical series than iodine
n24 5(b)(iii): damp litmus paper is bleached 2
n24 6(b)(i): number of neutrons in Na = 12 number of electrons in Ag+ = 46 number of protons in Na = 11 AND number of protons in Ag+ = 47 3
n24 6(b)(ii): 2,8,1
n24 7(a)(i): aqueous / dissolved in water
n24 7(a)(ii): filtration
n24 7(b)(ii): (H+) + OH– → H2O OH– H2O 2
n24 7(b)(iii): release of thermal energy
n24 7(b)(iv): the energy of the products is lower than the energy of the reactants OR the energy of the reactants is higher than the energy of the products
n24 8(a)(i): 1.0 0.5 2.0
n24 8(a)(ii): longer time / increases time / more time
n24 8(a)(iii): shorter time / decreases time / less time
n24 8(b)(ii): graphite

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