Chemistry / Topic coverage

Physical

Numerical machine: thermo, equilibrium, electrochem, solutions, gaseous — still ~half of Chem.

Weight highIntensity Core · dailyTrend Falling share300-target 50.3 /100high

Path to 300

Mark budget for this portion

At ~49.8% of chemistry weight, this portion should reliably deliver ~52 of your 100 chemistry marks — treat misses here as rank-droppers.

37.7Floor marks

50.3Target marks

57.8Stretch marks

49.8%Of subject weight

100Subject target

At a glance

Coverage metrics

120Tagged questions

49.8%Of Chemistry

17.14Average / year

2020Peak year (26 Q)

7/7Years present

Official · 2026

Syllabus map for this portion

Full Chemistry syllabus →

All Physical Chemistry units from mole concept through surface chemistry (bonding shared with inorganic).

Must cover from syllabus

Stoichiometry & concentration measures
Thermodynamics ΔG criteria
Ionic equilibrium buffers/Ksp
Nernst + conductance
Zero/first order kinetics + Arrhenius
Colligative + packing fractions

Gaps / exclusions to watch

Surface chemistry definitions (often neglected)
Solid state seven systems parameters

Unit 01

General topics (Mole & Stoichiometry)

high

Exam focusMole fraction/molarity/molality/normality; redox stoichiometry.

Syllabus points

Atoms/molecules; Dalton; mole concept; formulae; balanced equations
Calculations for redox, neutralisation, displacement
Concentration: mole fraction, molarity, molality, normality

Do / check

Convert all concentrations to one basis before mixing

Unit 02

States of Matter: Gases and Liquids

medium

Exam focusvan der Waals, rms velocities, vapour pressure/viscosity ideas.

Syllabus points

Gas laws; ideal gas; absolute temperature; van der Waals; kinetic theory velocities
Partial pressures; diffusion
Intermolecular interactions; liquids: vapour pressure, surface tension, viscosity

Do / check

Relate <v>, v_rms, v_mp to T before plugging numbers

Unit 03

Atomic Structure

medium

Exam focusBohr spectrum, quantum numbers, orbital shapes, Aufbau/Pauli/Hund.

Syllabus points

Bohr model; H spectrum; de Broglie; uncertainty
H-atom QM picture: energies, quantum numbers, ψ and probability density (plots), s/p/d shapes
Aufbau, Pauli, Hund

Do / check

Write n,l,m,s constraints before electronic configuration

Unit 04

Chemical Bonding and Molecular Structure

high

Exam focusHybridisation, MO diagrams to Ne₂, VSEPR shapes list in syllabus.

Syllabus points

Orbital overlap; covalent bond; hybridisation s/p/d
MO diagrams for homonuclear diatomics up to Ne₂; H-bond; polarity/dipole
VSEPR shapes: linear, angular, triangular, square planar, pyramidal, square pyramidal, TBP, tetrahedral, octahedral

Do / check

Count electrons carefully for MO bond order

Unit 05

Chemical Thermodynamics

high

Exam focusHess, ΔG criteria, entropy, lattice enthalpy.

Syllabus points

Intensive/extensive; state functions; First law; U, w (P–V), q; H; heat capacity; standard state; Hess
Enthalpy of reaction/fusion/vaporization/lattice
Second law; entropy; Gibbs energy; equilibrium & spontaneity criteria

Do / check

State function vs path function before cycle problems

Unit 06

Chemical and Ionic Equilibrium

high

Exam focusKp/Kc, Le Chatelier, buffers, salt hydrolysis, Ksp.

Syllabus points

Mass action; ΔG and ΔG°; Kp, Kc, Q; Le Chatelier
Ksp, common ion, pH, buffers; Brønsted/Lewis acids–bases; salt hydrolysis

Do / check

Write Q vs K before predicting shift

Unit 07

Electrochemistry

high

Exam focusNernst, conductance, Faraday, batteries/fuel cells/corrosion.

Syllabus points

Cells and cell reactions; standard potentials; electrochemical work; Nernst; series; galvanic emf
Faraday electrolysis; specific/equivalent/molar conductivity; Kohlrausch
Primary/secondary batteries; fuel cells; corrosion

Do / check

Write cell reaction and n before Nernst

Unit 08

Chemical Kinetics

high

Exam focusZero/first order integrated laws, Arrhenius, catalysis ideas.

Syllabus points

Rate, order, molecularity; rate law; half-life
Differential/integrated zero and first order; Arrhenius; activation energy
Homogeneous/heterogeneous catalysis; enzyme catalysis mechanism idea

Do / check

Confirm order before integrating

Unit 09

Solid State, Solutions, Surface Chemistry

medium

Exam focusfcc/bcc/hcp packing, colligative + van’t Hoff, adsorption isotherm basics.

Syllabus points

Crystalline solids; seven systems; close packing; fcc/bcc/hcp; defects; radius ratio
Henry, Raoult; ideal solutions; colligative properties; van’t Hoff factor
Physisorption/chemisorption; Freundlich; colloids; emulsions/surfactants/micelles (defs)

Do / check

Track i-factor carefully in colligative numericals

2020–2026

Year-wise appearance

Counts of tagged questions for this topic each year.

2026

2118

2217

2317

2416

2514

2612

Reading the pattern

Physical accounts for ~49.8% of tagged chemistry questions (2020–2026).
Trend signal: falling (early-window avg 20.3/yr vs recent avg 14.0/yr).
Appears in 7/7 tagged years; peak 2020 (26 Q), low 2026 (12 Q).
Dominant subtopics: Mixed (36), Mole/Gaseous (24), Electrochemistry (14), Thermodynamics (11).
Question-type mix: Numerical 49.2%, Multi correct 25.0%, Single correct 22.5%, Matching 3.3%.

Internal breakdown

Subtopic coverage

Start with the top subtopics — they usually carry most of this portion’s weight.

Mixed36 · 30%
Mole/Gaseous24 · 20%
Electrochemistry14 · 11.7%
Thermodynamics11 · 9.2%
Equilibrium7 · 5.8%
Kinetics7 · 5.8%
Atomic Structure7 · 5.8%
Solutions6 · 5%
Solid State4 · 3.3%
Surface4 · 3.3%

Subtopic	Count	Share	Years (count)
Mixed	36	30%	2020·12 2021·5 2022·8 2023·1 2024·5 2025·5
Mole/Gaseous	24	20%	2020·7 2021·3 2022·1 2023·6 2024·4 2025·2 2026·1
Electrochemistry	14	11.7%	2020·1 2021·3 2022·3 2023·2 2024·2 2025·2 2026·1
Thermodynamics	11	9.2%	2020·3 2021·2 2022·1 2023·1 2024·1 2025·1 2026·2
Equilibrium	7	5.8%	2020·1 2021·2 2022·2 2023·1 2025·1
Kinetics	7	5.8%	2021·1 2023·1 2024·2 2025·1 2026·2
Atomic Structure	7	5.8%	2022·1 2023·2 2024·2 2026·2
Solutions	6	5%	2020·1 2023·1 2025·1 2026·3
Solid State	4	3.3%	2020·1 2021·1 2022·1 2023·1
Surface	4	3.3%	2021·1 2023·1 2025·1 2026·1

Exam form

Type & difficulty mix

Question types

Numerical — 59 questions (49.2%)
Multi correct — 30 questions (25%)
Single correct — 27 questions (22.5%)
Matching — 4 questions (3.3%)

Difficulty (heuristic)

M — 74 questions
H — 46 questions

Use for planning load only — not an official difficulty label.

Focused study

Plan for this portion

Must know

First law / work for irreversible paths
Kp/Kc & Le Chatelier quantitative
Nernst & conductance
Colligative & vapour composition
Rate laws & half-life

Common traps

Wrong system vs surroundings sign
Mole fraction vs molality mix-ups

Weekly drill checklist

2 thermo/equilib
2 electrochem/solutions
1 kinetics
1 gaseous state

Prerequisite chain

Mole→thermo→equilib→electrochem→kinetics/solutions

Often joins with

Inorganic (bonding energetics)Organic (practical analysis)

Paper pointers

Sample tagged questions

Use these as deliberate practice targets from past papers.

Year	Paper	Q	Subtopic	Type	Diff
2020	P1	Q1	Mole/Gaseous	SC	M
2020	P1	Q2	Mixed	SC	M
2020	P1	Q4	Mole/Gaseous	SC	M
2020	P1	Q5	Mixed	SC	M
2020	P1	Q7	Thermodynamics	MC	H
2020	P1	Q11	Mole/Gaseous	MC	H

Connections

Related mixed joins

Where this topic must connect with another concept in one stem.

Chemistry2022 · Paper 1 · Q6–Q8numerical

Organic practical + named-reaction NUM burst

Organic practical/analysis+Named reactions+Physical mixed NUM nearby

Knowledge bridge

Step 1: decode practical/analysis data into a count or identification. Step 2: push named-reaction reagents to the major product / stoichiometric ask. Step 3: keep Physical mixed NUMs mentally separate so Organic logic is not diluted.

Why it feels hard

Organic numericals feel unfamiliar if you only practised MCQ mechanisms.

What to practise

Convert two named reactions per week into a numerical ask (moles, isomers, mass).

Open 2022 year review →

Chemistry2021 · Paper 1 · Q5–Q9linked-numerical

Organic linked NUM + Physical thermo/mixed

Organic named/reactions (linked)+Physical thermodynamics+Metallurgy / mixed Physical

Knowledge bridge

Step 1: resolve the Organic linked numerical using reaction stoichiometry. Step 2: switch to thermo/mixed Physical NUMs with fresh variables. Step 3: keep metallurgy facts (if present) as recall, not calculation, items.

Why it feels hard

Branch switching inside one NUM section.

What to practise

Label each Chem NUM as Org/Phy/Inorg in the margin before solving.

Open 2021 year review →

Chemistry2020 · Paper 1 · Q16–Q17numerical

Physical mixed numerical pair

Physical – Mixed+Mole / gas / thermo blend+Numerical

Knowledge bridge

Step 1: parse which Physical sub-ideas are fused (mole + thermo, gas + equilibrium, etc.). Step 2: write governing equations for each piece. Step 3: combine numerically without dropping stoichiometric factors.

Why it feels hard

‘Mixed’ Physical tags mean the stem will not stay in one textbook chapter.

What to practise

Practise deliberately cross-chapter Physical sets (thermo×gases×equilibrium).

Open 2020 year review →

Chemistry

Other portions

Organic Inorganic

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