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How To Score An A In O Level & IGCSE Chemistry (Step-By-Step Strategy Students Actually Follow)

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How To Score An A In O Level & IGCSE Chemistry (Step-By-Step Strategy Students Actually Follow)

Step 1: Build A Complete Topic-Map From Day 1

Understand What the Subject Wants From You

  • Chemistry is 70% memory + 30% understanding.
  • The syllabus expects:
    • Definition accuracy
    • Reaction patterns
    • Knowing trends
    • Strong practical knowledge
    • Problem-solving in calculations
  • Students who score A build topic maps early.

How To Build Your Topic-Map

  • Make one map per chapter:
    • Key definitions
    • Key formulas
    • Key reactions
    • Key trends
    • High-weight questions
  • Add sub-maps for:
    • Stoichiometry
    • Electrolysis
    • Rates
    • Organic Chemistry
    • Acids, Bases & Salts
    • Practical Techniques

Step 2: Master the “Non-Negotiable” Chemistry Definitions

How A Students Memorise Definitions

  • Short, one-line, keyword-based bullets.
  • No extra words.
  • Memorised using:
    • Flashcards
    • Active recall
    • Weekly revision sessions

Core Definitions You Must Master

  • Atom
  • Isotope
  • Ion
  • Mole
  • Empirical formula
  • Molecular formula
  • Electrolysis
  • Oxidation & reduction
  • Rate of reaction
  • Catalyst
  • Acid, base, alkali
  • Polymer
  • Exothermic & endothermic
  • Activation energy

Sub-Techniques

  • Break each definition into:
    • What it is
    • What makes it unique
    • What keyword MUST appear

Step 3: Build the A-Student Calculation System

Calculation Types That Come Every Year

  • Moles
  • Mass-mole conversions
  • Gas volumes
  • Concentration
  • Empirical & molecular formula
  • Stoichiometric ratios
  • Limiting reactants
  • Percentage yield
  • Percentage purity
  • Titrations

The A-Student Calculation Routine

  • Convert cm³ to dm³ first
  • Always write the formula first
  • Substitute values with units
  • Solve step by step
  • Round only the final answer

Sub-Strategy

  • Do 10–12 calculation questions every day.
  • Re-solve wrong questions after 48 hours.
  • Build a formula sheet and revise daily.

Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Chemistry Free Material

Step 4: Learn Reaction Patterns Instead of Memorising Random Reactions

Why A Students Learn Patterns Instead of Lists

  • Chemistry follows predictable behaviour.
  • Understanding patterns = easy full marks.

Acid Reaction Patterns

  • Acid + metal → salt + hydrogen
  • Acid + base → salt + water
  • Acid + carbonate → salt + water + carbon dioxide

Organic Reaction Patterns

  • Alkane + halogen → substitution (requires UV)
  • Alkene + bromine → addition (brown → colourless)
  • Alcohol oxidation → aldehyde → carboxylic acid
  • Alcohol + carboxylic acid → ester + water
  • Cracking → smaller alkanes + alkenes

Metal Reaction Patterns

  • More reactive metal displaces less reactive metal
  • Potassium, sodium, calcium react with water violently
  • Magnesium reacts with steam
  • Copper, silver, gold do not react with acids

Sub-Pattern Strategy

  • Make one page for each pattern.
  • Memorise using comparisons:
    • Addition vs substitution
    • Acid reactions vs neutralisation
    • Oxidation vs reduction

Step 5: Use the A-Student Explanation Template

Explanation Template (You Must Use This In The Exam)

  • Start with cause
  • Describe mechanism
  • End with effect
  • Keep each line one bullet

Examples

Why increasing temperature increases rate

  • Particles gain kinetic energy
  • They collide more frequently
  • More collisions have energy to overcome activation energy
  • Rate increases

Why ionic compounds conduct when molten

  • Ions become free to move
  • Movement of ions allows current to flow

Sub-Rule

  • Examiners reward:
    • Cause
    • Mechanism
    • Result
    • Scientific keyword

Step 6: Practical Skills (30% of Exam Weight) — A Students Don’t Ignore

Observation Skills

  • Use correct colours only:
    • Blue precipitate
    • Green precipitate
    • Brown precipitate
    • White precipitate
    • Colourless (never “clear”)

Gas Tests

  • Hydrogen → pop
  • Oxygen → relight
  • CO₂ → milky
  • Chlorine → bleaches
  • Ammonia → red to blue

Ion Tests

  • Sodium hydroxide vs ammonia
  • Solubility patterns of precipitates
  • Flame colours:
    • Lithium red
    • Sodium yellow
    • Potassium lilac
    • Calcium orange-red
    • Copper blue-green

Graphs & Tables

  • Use at least 50% of the graph
  • Label axes with units
  • Plot accurate points
  • Draw best-fit line
  • Use large triangle for gradient

How A Students Prepare

  • They write summaries for:
    • Cation tests
    • Anion tests
    • Flame tests
    • Gas tests
    • Chromatography
    • Filtration & crystallisation
    • Distillation

Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Chemistry Free Material

Step 7: Learn the Topic-Wise Weightage (The Secret Most Students Ignore)

High-Weight Topics for A Students

  • Stoichiometry (moles, reacting masses)
  • Electrolysis
  • Rates of reaction
  • Acids & bases
  • Organic chemistry
  • Periodic table & trends
  • Metals & reactivity series
  • Practical techniques

Medium-Weight Topics

  • Atmosphere & environment
  • Water treatment
  • Air pollutants
  • Chemical energetics

Low-Weight but Easy Marks

  • States of matter
  • Separation techniques
  • Simple equations

A Student Strategy

  • Start with high-weight topics
  • Build mid-weight topics after
  • Finish low-weight topics last
  • Weekly rotation:
    • 2 high weight
    • 1 medium
    • 1 practical

Step 8: Past Papers — The A-Student Way

MCQs

  • Do 20 per day
  • Mark immediately
  • Create flashcards for mistakes
  • Track patterns of wrong answers

Structured Questions

  • Answer in bullets
  • Underline given values
  • Show clear working
  • Use keywords from mark schemes

Practical Questions

  • Write down:
    • Observations
    • Errors
    • Improvements
    • Variables

A-Student Weekly Cycle

  • 4 MCQ sets
  • 2 structured sections
  • 1 practical section
  • 1 mock under timed conditions

Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Chemistry Free Material

Step 9: Build a Formula & Reaction Sheet

Formula Sheet Must Include

  • Mole formulas
  • Empirical/molecular formulas
  • Gas volumes
  • Concentration conversions
  • Yield & purity formulas
  • Bond energy formula

Reaction Sheet Must Include

  • Acid reactions
  • Alkane vs alkene reactions
  • Alcohol reactions
  • Carboxylic acid reactions
  • Metal reactions
  • Displacement rules
  • Test results

Sub-Technique

  • Rewrite the sheet every 7 days
  • Memorise using active recall

Step 10: Weekly Revision System (The A-Student Advantage)

Weekly Breakdown

  • Day 1:
    • Stoichiometry
  • Day 2:
    • Electrolysis
  • Day 3:
    • Acids, bases, salts
  • Day 4:
    • Organic chemistry
  • Day 5:
    • Practical chemistry
  • Day 6:
    • Mixed past paper
  • Day 7:
    • Revise every summary sheet

Sub-Rules

  • Never skip revision
  • Keep all notes bullet-based
  • Create mindmaps every Sunday

Written and Compiled By Sir Hunain Zia, World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change O Level And IGCSE Chemistry Free Material

Step 11: Exam-Hall Strategy for A

Before You Start

  • Read entire paper
  • Mark easy questions
  • Start with easiest first

During Paper

  • Bullet-point answers
  • Avoid long paragraphs
  • Always state units
  • Don’t overwrite explanations
  • Use command-word logic

For Calculations

  • Write formula
  • Substitute
  • Solve
  • Round at the end

For Explanation Questions

  • Use cause → mechanism → effect
  • Avoid storytelling
  • Keep bullets short
Hunain Zia

Hunain Zia has previously achieved considerable success in the high-school educational stream, gaining a massive 154 Total A Grades and 7 Major Distinctions, a process in which he broke/ set 11 different world records, including the most A grades ever achieved, most subjects ever appeared in, most distinctions, gaining distinctions across two separate boards (Pearson Edexcel and CAIE) within the same year/ ever, and even 19 hours of constant examination. All records stand intact today. Hunain pursued his Honors Accounting Degree from the prestigious Bentley University, and then completed an LLB (in Honors) from University of London. Currently, he manages multiple social and commercial projects, has founded digital streams and works tirelessly in the education sector.

Educate A Change focuses on truly bringing change in the educational sector worldwide. All our courses are designed to ensure success, and provide complete preparation without requiring any other external material. Therefore, it takes away the expense of academies, books, past paper compilations and other miscellaneous items. Instead, by just the courses we offer, the student can prepare fully for the best grades in their CAIEs, Edexcel and other high-school exams. The earnings from our course-sales are invested in social projects and growing the free educational activities of Educate A Change.