All 82 decoded questions of ESAT 2018, in paper order. · A question can reward more than one move, so the counts overlap.
ENGAA 2018 Section 1, Part B (Mathematics questions) 18 decoded 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 The paper at a glance, coloured by move. Click a square to open its question; empty squares are not decoded yet.
55 Oxygen sag below organic pollution: bacteria strip the oxygen, and indicator species track the curve Key method Biology Ecology & Plant Physiology 3 other sittings Same method, other sittings
56 Heterozygote advantage keeps a harmful recessive allele in a population under pressure Key method Biology Inheritance, Variation & Evolution 1 other sitting Same method, other sittings
57 Animal cells never have a cell wall or chloroplasts: use it as an instant eliminator Structure implies function: name the cell or tissue from what it is shown doing, then read off its properties The biological organisation ladder: check every noun sits at the level (cell, tissue, organ) the option claims One person, one genome: division type, stem cells, and same DNA but different proteins Pavlov Biology Cells 4 other sittings Same method, other sittings
58 Ecological abundance: frequency is presence in quadrats, density is count per area, and both need a random sample Key method Biology Ecology & Plant Physiology 5 other sittings Same method, other sittings
59 Probability of a specific sex and a specific genotype: multiply the two independent chances Key method Biology Inheritance, Variation & Evolution 3 other sittings Same method, other sittings
60 Mitosis keeps the chromosome number and makes two cells, meiosis halves it and makes four Key method Biology Membrane Transport, Cell Division & Reproduction 6 other sittings Same method, other sittings
61 Trace the auxin: shoots bend to light, roots to gravity, driven by uneven hormone from an intact tip Pavlov Biology Ecology & Plant Physiology 2 other sittings Same method, other sittings
62 Osmosis moves water toward the more concentrated solution The three osmosis definition traps examiners plant in statements Rate of diffusion or osmosis is set by the steepness of the gradient Pavlov Biology Membrane Transport, Cell Division & Reproduction 7 other sittings Same method, other sittings
63 DNA base arithmetic: pairing rules bind the whole molecule, never a single strand Key method Biology DNA, Protein Synthesis & Gene Technology 3 other sittings Same method, other sittings
64 Follow the product to fix the pH direction and read the indicator Structure implies function, and every enzyme is specific to its substrate Key method Biology Enzymes 2 other sittings Same method, other sittings
65 A mutation present in every cell must have arisen in a gamete or the fertilised egg Key method Biology Inheritance, Variation & Evolution 1 other sitting Same method, other sittings
66 Genetic engineering means moving or altering a gene; cloning a whole nucleus does not Key method Biology DNA, Protein Synthesis & Gene Technology 1 other sitting Same method, other sittings
67 Plateaux and the compensation point: a level rate means another factor limits, a falling rate means denaturation Key method Biology Ecology & Plant Physiology 3 other sittings Same method, other sittings
68 Genetic engineering means moving or altering a gene; cloning a whole nucleus does not Key method Biology DNA, Protein Synthesis & Gene Technology 1 other sitting Same method, other sittings
69 Read gene facts off a cross-organism sequence table Key method Biology DNA, Protein Synthesis & Gene Technology only this sitting Same method, other sittings
This one has only struck here so far.
70 Separate chromosome, DNA molecule and strand, and watch for the replication doubling Key method Biology Membrane Transport, Cell Division & Reproduction 3 other sittings Same method, other sittings
71 Natural selection edits pre-existing random variation, the environment never writes it Key method Biology Inheritance, Variation & Evolution 4 other sittings Same method, other sittings
72 Gene, allele and base sequence are three different levels Pavlov Biology DNA, Protein Synthesis & Gene Technology only this sitting Same method, other sittings
This one has only struck here so far.
NSAA 2018 Section 1 Part B (ESAT Physics) 18 decoded 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 The paper at a glance, coloured by move. Click a square to open its question; empty squares are not decoded yet.
37 Read a nuclide symbol into protons, neutrons and electrons Pavlov Chemistry Atomic Structure, Bonding & the Periodic Table 5 other sittings Same method, other sittings
38 Screen an equilibrium with the three Le Chatelier levers Key method Chemistry Rates of Reaction & Energetics 2 other sittings Same method, other sittings
39 Aqueous electrolysis discharge rules: below hydrogen deposits, halide gives the halogen Cathode is reduction, anode is oxidation, and electrons flow from plus to minus outside Key method Chemistry Electrolysis & Metals 5 other sittings Same method, other sittings
40 Relative atomic mass as an abundance-weighted mean, forwards or reversed Bound the relative atomic mass between the isotope masses to eliminate options Electron configuration gives the Period, the Group and the element Tunnel Chemistry Atomic Structure, Bonding & the Periodic Table 6 other sittings Same method, other sittings
41 Pick the separation technique from the property that differs Key method Chemistry Organic Chemistry, Separation & Analysis 2 other sittings Same method, other sittings
42 Aqueous electrolysis discharge rules: below hydrogen deposits, halide gives the halogen Track the bulk solution, not just the electrodes: concentration and pH changes Key method Chemistry Electrolysis & Metals 5 other sittings Same method, other sittings
43 Judge a reaction as redox from its type before assigning oxidation numbers Key method Chemistry Chemical Reactions, Acids, Bases & Redox 5 other sittings Same method, other sittings
44 Isoelectronic species share an electron count but differ in protons Key method Chemistry Atomic Structure, Bonding & the Periodic Table 2 other sittings Same method, other sittings
45 Read the balanced equation directly in gas volumes, and track the change in the number of gas molecules Pin exactly what is asked: the examiner plants the natural intermediate value as an option Key method Chemistry Quantitative Chemistry 5 other sittings Same method, other sittings
46 Classify the structure and bonding, then read off the property Key method Chemistry Atomic Structure, Bonding & the Periodic Table 6 other sittings Same method, other sittings
47 Purity and hydration are just multiplying factors: scale in the right direction and the pre-scaled value is the trap Key method Chemistry Quantitative Chemistry 2 other sittings Same method, other sittings
48 Recall Group 1 and Group 17 trends whole, without deriving them Pavlov Chemistry Atomic Structure, Bonding & the Periodic Table 3 other sittings Same method, other sittings
49 Rf equals spot distance over solvent-front distance Interpreting a chromatogram: purity, identity, mobility and phases Pavlov Chemistry Organic Chemistry, Separation & Analysis 6 other sittings Same method, other sittings
50 Gas volume to moles: convert cm3 to dm3 before dividing by 24 Pavlov Chemistry Rates of Reaction & Energetics 1 other sitting Same method, other sittings
51 Balance a skeleton equation one element at a time, most constrained first Tunnel Chemistry Chemical Reactions, Acids, Bases & Redox 3 other sittings Same method, other sittings
52 Back titration: acid that reacted equals acid supplied minus acid left over Tunnel Chemistry Quantitative Chemistry 1 other sitting Same method, other sittings
53 Ion charges fix the formula, the reacting ratio and the number of ions Limiting reagent by moles over coefficient, and the graph plateau marks the exact stoichiometric point Pavlov Chemistry Quantitative Chemistry 4 other sittings Same method, other sittings
54 Base heat and yield on the equilibrium amount, not the input Key method Chemistry Rates of Reaction & Energetics only this sitting Same method, other sittings
This one has only struck here so far.
NSAA 2018 Section 1, Part A (Mathematics questions) 16 decoded 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 The paper at a glance, coloured by move. Click a square to open its question; empty squares are not decoded yet.
1 Fill the two-way table for overlapping categories Tunnel Prob & Stats Probability & Statistics 2 other sittings Same method, other sittings
2 3D solids: equating volumes and surface areas algebraically Tunnel Pure Geometry 5 other sittings Same method, other sittings
3 Implicit line equations: isolate y to find the gradient safely Pavlov Pure Coordinate Geometry 3 other sittings Same method, other sittings
4 Circle theorems: angle chasing Tunnel Pure Geometry 2 other sittings Same method, other sittings
5 Setting up the proportionality constant Tunnel Pure Ratio & Proportion 5 other sittings Same method, other sittings
6 Scaling laws for similar figures and solids Pavlov Pure Ratio & Proportion 4 other sittings Same method, other sittings
7 Convert means into absolute totals Pavlov Prob & Stats Probability & Statistics 4 other sittings Same method, other sittings
8 Areas bounded by intersecting lines: use an axis as the base Key method Pure Coordinate Geometry 3 other sittings Same method, other sittings
9 Scaling laws for similar figures and solids Pavlov Pure Ratio & Proportion 4 other sittings Same method, other sittings
10 Regular polygons: work with exterior angles, not interior Pavlov Pure Geometry 3 other sittings Same method, other sittings
11 Successive percentage changes as a product of decimal multipliers Pavlov Pure Ratio & Proportion 5 other sittings Same method, other sittings
12 Pick a convenient starting value for pure ratio and percentage problems Key method Pure Ratio & Proportion 1 other sitting Same method, other sittings
13 Bearings: use back-bearings and subtraction to find angles Pavlov Pure Geometry 3 other sittings Same method, other sittings
14 Avoid overlapping regions in Venn diagrams Tunnel Prob & Stats Probability & Statistics only this sitting Same method, other sittings
This one has only struck here so far.
15 Circle theorems: angle chasing Tunnel Pure Geometry 2 other sittings Same method, other sittings
18 Calculate the complement for at least one or complex conditions Key method Prob & Stats Probability & Statistics 1 other sitting Same method, other sittings
NSAA 2018 Section 1, Part C (Chemistry questions) 4 decoded 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 The paper at a glance, coloured by move. Click a square to open its question; empty squares are not decoded yet.
35 Sector and Segment Mechanics Tunnel Pure Trigonometry 2 other sittings Same method, other sittings
39 Discarding the Extraneous Root Three Consecutive Terms Equation Key method Pure Sequences & Series 3 other sittings Same method, other sittings
45 Distance relations: square both sides to avoid surds Pavlov Pure Coordinate Geometry only this sitting Same method, other sittings
This one has only struck here so far.
51 Fundamental Theorem for Net Change Tunnel Pure Integration only this sitting Same method, other sittings
This one has only struck here so far.
NSAA 2018 Section 1, Part D (Biology questions) 9 decoded 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 The paper at a glance, coloured by move. Click a square to open its question; empty squares are not decoded yet.
73 Symmetric Limits and Even Functions Area Between Curves via Single Integral Pavlov Pure Integration 2 other sittings Same method, other sittings
75 Factor Out, Never Divide Pavlov Pure Trigonometry 1 other sitting Same method, other sittings
77 Roots via the Discriminant System to Single Quadratic Key method Pure Algebra, Functions & Graphs 3 other sittings Same method, other sittings
79 AP Conditions to Linear Relations Tunnel Pure Sequences & Series 1 other sitting Same method, other sittings
81 Sum of Logarithms → Product of Arguments Pavlov Pure Exponentials & Logarithms 1 other sitting Same method, other sittings
83 Extremes on a circle: use geometry, not calculus Key method Pure Coordinate Geometry 1 other sitting Same method, other sittings
85 Look Ahead in Binomial Expansions Key method Pure Sequences & Series 2 other sittings Same method, other sittings
87 Symbolic Evaluation of Parametric Integrals Tunnel Pure Integration only this sitting Same method, other sittings
This one has only struck here so far.
89 Geometric Optimisation Tunnel Pure Differentiation 2 other sittings Same method, other sittings
NSAA 2018 Section 1, Part E (Mathematics questions) 17 decoded 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 The paper at a glance, coloured by move. Click a square to open its question; empty squares are not decoded yet.
19 Alpha and beta decay bookkeeping: fix the alpha count from the mass number first Tunnel Physics Radioactivity 5 other sittings Same method, other sittings
20 Label the circuit with the two invariants, then carry the one given number across In a two state question, lock the invariant from state one before touching state two Tunnel Physics Electricity & Magnetism 7 other sittings Same method, other sittings
21 Classify a wave on the spectrum by converting band edges with the wave equation Tunnel Physics Waves, Sound & the Electromagnetic Spectrum 3 other sittings Same method, other sittings
22 Read a motion graph by gradient and area, one phase at a time Distance, displacement and average speed are three different readings of the same motion Tunnel Physics Kinematics & Forces 5 other sittings Same method, other sittings
23 Power is energy per second: convert the time first, and use force times velocity at constant speed Efficiency chain: multiply going out, divide coming back, never add the losses Pavlov Physics Energy, Work & Momentum 2 other sittings Same method, other sittings
24 Heat transfer is driven by the temperature difference alone, never by the individual temperatures Conduction along a bar: rate is proportional to area times temperature difference, divided by length Which expression questions: settle them by units and by one variable at a time Key method Physics Thermal Physics 4 other sittings Same method, other sittings
25 Efficiency chain: multiply going out, divide coming back, never add the losses Tunnel Physics Energy, Work & Momentum 1 other sitting Same method, other sittings
26 The bridge between momentum and kinetic energy Key method Physics Energy, Work & Momentum 2 other sittings Same method, other sittings
27 Count-rate questions: subtract the background before reading anything Key method Physics Radioactivity 1 other sitting Same method, other sittings
28 Free body first: list every force with its sign, then set the resultant equal to ma Tunnel Physics Kinematics & Forces 3 other sittings Same method, other sittings
29 Total path of an oscillating particle is four times the amplitude per cycle Key method Physics Waves, Sound & the Electromagnetic Spectrum 3 other sittings Same method, other sittings
30 Turn what you are given into a mass before you divide by a volume Pavlov Physics Matter 2 other sittings Same method, other sittings
31 Read a motion graph by gradient and area, one phase at a time Steady motion is a free equation, and after a perturbation only the change is unbalanced Tunnel Physics Kinematics & Forces 6 other sittings Same method, other sittings
32 Across a boundary the frequency is fixed, so speed and wavelength change together Pavlov Physics Waves, Sound & the Electromagnetic Spectrum 2 other sittings Same method, other sittings
33 Alpha and beta decay bookkeeping: fix the alpha count from the mass number first Nuclear reactions: balance nucleon number and proton number across the arrow Tunnel Physics Radioactivity 5 other sittings Same method, other sittings
34 When the resistances are identical or never given, call each one R and let it cancel Choose the power formula by the shared quantity, then split power as R or as one over R Key method Physics Electricity & Magnetism 6 other sittings Same method, other sittings
35 In a two state question, lock the invariant from state one before touching state two For a non ohmic component the graph is its Ohm law: the circuit picks the axis Key method Physics Electricity & Magnetism 6 other sittings Same method, other sittings
