WAEC Chemistry: Topics to Focus On

Chemistry can feel like three subjects at once: a calculation subject (the mole), a memory subject (reactions and tests) and a reasoning subject (why things react). A good plan treats them differently, and starts with the topics that the rest depend on.

The three groups below are our study-priority judgement for 2027, built on which topics the others depend on; WAEC does not publish how often each topic is set, and this is not an official weighting. The paper format, the practical component and the marking approach are in the syllabus on waecnigeria.org, so this guide gives no question numbers, marks or timings.

The map of the subject

Group one: must master

Atomic structure, the periodic table and bonding. Electron arrangement, trends across periods and down groups, and the three bond types: ionic, covalent and metallic. Questions on properties (melting point, conductivity, solubility) usually come from understanding bonding.

The mole and stoichiometry. The mole concept, relative atomic and formula masses, balanced equations, and calculations on reacting masses, volumes and concentrations. This is the core of the numerical side of the paper.

Original practice: How many moles are there in 18 g of water? (H = 1, O = 16.) The molar mass of water is 18 g/mol, so 18 g is 1 mole. Start every mole question by writing the formula you will use and the molar mass.

Acids, bases and salts. Properties, pH, neutralisation, titration, preparation of salts and solubility rules. This topic is close to the practical work, so it repays hands-on practice.

Group two: commonly tested

Oxidation, reduction and electrolysis. Oxidation numbers, redox reactions, electrolysis of molten and aqueous compounds, products at each electrode, and applications such as electroplating. Draw the cell and label the anode, cathode and ions; many questions are answered from the picture.

Organic chemistry. Alkanes, alkenes, alkynes, alkanols, alkanoic acids and esters; their general formulae, naming, properties and reactions; and polymers. The pattern is: learn the homologous series, then the reactions of each. Make a table with the functional group, the general formula and a typical reaction.

Rates, equilibrium and energy. Factors that affect the rate of reaction, Le Chatelier's principle in plain words, and exothermic versus endothermic changes. Conceptual; learn them with examples.

Gas laws. Boyle's, Charles's and the combined law; usually a short calculation with a clear structure.

Group three: lower priority

• Industrial chemistry. Manufacture of ammonia, sulphuric acid and other named processes on the syllabus: raw materials, conditions and uses. Learn the main steps and conditions in a flowchart.
• Environmental chemistry. Pollution, water treatment, acid rain, greenhouse effect. Learn causes, effects and controls.
• Qualitative analysis detail. Know the standard tests; the rare ones can wait.

These may feel like "story" topics, but they are easy marks when you have learned the flowcharts. Many candidates leave them until the last night and then rush. A better habit is one flowchart a week from the start: for the Haber process, for instance, write the raw materials (nitrogen from air, hydrogen from natural gas or water), the iron catalyst and the product, ammonia, and then say in a line what the ammonia is used for.

The practical component

Chemistry at WAEC includes practical skills. Read the syllabus for how they are examined. Whatever the format, practise the tests for common gases (hydrogen, oxygen, carbon dioxide, chlorine, ammonia), the tests for common cations and anions, and titration technique including how to read a burette and calculate concentration. Our WAEC Chemistry practical tips cover the common mistakes.

How to practise

Reaction cards and the periodic table both suit the recall methods in how to memorise faster. Keep an error log using the method in how to use past questions: mole errors are often arithmetic, while bonding errors are usually conceptual.

For the overall strategy, read how to pass WAEC Chemistry.

Mistakes to avoid

1. Learning reactions without balancing equations.
2. Starting mole problems without writing the formula and molar mass.
3. Mixing up anode and cathode in electrolysis.
4. Chasing "expo" papers. They waste revision time and put your result at risk.

A readiness check

Close each group with a closed-book test. Can you write the electron arrangement of the first twenty elements? Can you do a reacting-mass calculation from a balanced equation? Can you name the products at each electrode in a simple electrolysis? Can you name and draw the first four alkanes? Any "no" means going back before you add new material. The test shows whether your trouble is the concept, the arithmetic or the vocabulary.

Practise the topics

Begin with structure and the mole, then move on through the groups. ExamPadi offers free WAEC Chemistry practice with worked explanations and a timed CBT mode, drawn from a bank of 46,182 questions across the four exam bodies. The WAEC hub covers your other subjects. No plan can promise a particular grade, but starting with the foundation topics makes the rest of the syllabus far less intimidating.