Chemistry is an elective science for school candidates and for private candidates. WAEC sets the paper. Glearn Technologies writes this guide. Glearn does not set the paper, and glearn does not publish a pass rate. Read the timetable for your own series. Anna marks WASSCE Chemistry. Kevin marks BECE Science.
Objective, theory, and the practical paper
The examination has three kinds of paper: an objective paper, a theory paper, and a practical paper. The practical paper is either work you carry out with apparatus, or an alternative to practical work that you answer in writing. The timetable for your series names each paper and gives the time. This page does not copy those times or the marks, because a later file can change them. If the timetable and this page disagree, follow the timetable.
Paper 1 is the objective paper. The items come from the syllabus, and you answer the items the paper asks you to answer.
Paper 2 is the theory paper. It mixes short written answers, explanations, and calculations. You answer a choice of the questions, not every one. Read the instruction on the front of the paper. A calculation with no working is harder to mark than one that shows each step.
The practical paper tests an experiment you do, or an experiment you write about. Qualitative work asks what you observe and what you infer. Volumetric work asks for readings you can follow, then a calculation. When your entry is the alternative to practical work, you still describe the method, the observation and the conclusion. Confirm the name on the WAEC Ghana timetable. Glearn does not decide which version a centre sits.
Topic areas to revise
These are the areas candidates revise for WASSCE Chemistry. A heading is not a promise that every unit appears on your paper. Glearn does not host the WAEC file. If the file your school gives you uses a different name, follow the file.
1. Atomic structure, periodicity and bonding
Protons, neutrons and electrons, and how the arrangement of electrons leads to the periodic table. Ionic bonding transfers electrons. Covalent bonding shares them. Say which one the substance uses, and one property that follows.
2. The mole and chemical equations
Amount of substance, molar mass, and a balanced equation. The mole ratio comes from that equation. Mass on its own is not a ratio of moles.
3. Acids, bases, salts, energy and rates
How acids and bases behave, how salts form, and what changes the speed or the energy of a reaction. Strong is not the same word as concentrated.
4. Organic chemistry
The families of carbon compounds you meet in class, their general behaviour, and a test that tells one family from another. Name the observation, not only the reagent.
5. Metals and practical analysis
How metals and other elements behave, then qualitative tests and volumetric work. An observation and an inference are two different sentences.
WASSCE syllabusWASSCE Chemistry past questionsAtomic structureChemical bondingThe moleAcids, bases and saltsOrganic chemistry
How to answer theory and practical questions
Theory in Chemistry is part explanation and part arithmetic. Practical work is part what you saw and part what you calculated. Keep those jobs apart.
1. Match the command
Define is the meaning. State is a short fact. Explain is a fact plus a reason. Calculate is the working, not a definition of the quantity. A definition does not answer a question that asked for a test or a mass.
2. Answer every part you were given
A question in parts is several marks. Label (a), (b) and (c) and do not skip the easy part at the end because the calculation took longer than you hoped.
3. Lead with the point
In an explanation, write the point in the first line, then the reason. In a calculation, write the relationship you are using before you substitute.
4. Separate observation and inference
What you saw is the observation. What it tells you is the inference. A colour you did not see, or a name of a salt with no observation, is not evidence.
5. Record volumetric work so it can be followed
A table of readings comes before the average you use. Use the readings the instruction tells you to use. Then calculate. A single number with no table is hard to mark.
6. Obey the rubric
Answer the number of questions the paper asks for. An extra unfinished calculation does not replace one you were required to attempt.
Calculations, equations and the mole
Most calculation marks are for a relationship you show, a conversion you do on purpose, and a unit on the final quantity. The mole is the amount of substance. It is not a mass.
1. Balance the equation first
A chemical equation shows what reacts and what is produced. Count each kind of atom on both sides. Do not change a formula to force a balance. Change the numbers in front of the formulas. Add state symbols when the question asks for them.
2. Take the mole ratio from the equation
The numbers in front of the formulas are the mole ratio. The masses you were given are not that ratio. For a reaction whose equation shows one mole reacting with one mole, the ratio is 1 to 1. Use the ratio your balanced equation actually shows.
3. Turn a mass into an amount
When the question gives a mass, the amount in moles is that mass divided by the molar mass. The molar mass comes from the relative atomic masses the question gives, or from the values your syllabus uses. Do not invent a molar mass.
4. Convert the volume before you multiply
Concentration links amount to volume. Put the volume into the unit the concentration uses before you multiply or divide. Mixing a mass in grams with a volume you have not converted is a common way to miss the answer by a large factor.
5. Show the working and the unit
Each line should be readable on its own. Keep extra digits through the working and round at the end, to the precision the question asks for. Put the unit on the final quantity. This page does not invent a rule about how many marks a rounding error costs.
6. Write an ionic equation only when asked
An ionic equation keeps the species that change. Ions that appear unchanged on both sides are spectators, and you leave them out. Check that charge, as well as atoms, still balances.
A short way to revise
Rotate the three papers. A week of definitions with no equation and no titration table leaves the calculation and the practical paper cold.
1. Give each paper a turn
One session for objective items, one for a theory answer that includes a calculation, one for a practical account or a results table. Do not save volumetric work for the night before.
2. Redo one mole question with the book closed
Balance the equation, write the ratio, convert the unit, and put the unit on the answer. Then open the book and see which line failed.
3. Reject the wrong options
On an objective item, say why the other options fail. An equation that is not balanced is a reason to reject an option, not a detail to ignore.
4. Have the answer marked
Anna marks WASSCE Chemistry on glearn. Kevin marks BECE Science. A written answer is marked point by point. Practise with Kevin and Anna on glearn.now. The first questions need no account.
5. Keep Chemistry inside the wider plan
The revision plan orders the weeks across every subject you sit. Integrated Science uses some of the same ideas and is still a different paper. This page does not copy a date.
WASSCE revision planHow to pass the WASSCEWASSCE Integrated Science tipsTry WASSCE practice free
Mistakes chief examiners keep returning to
WAEC chief examiners write a report after a sitting. This page describes the habits in general. It does not quote a report, and it does not give a figure.
1. An equation that is not balanced
Reports often describe equations that do not have the same atoms on both sides, or a formula that was changed to make the count look right. Balance with the numbers in front.
2. A mass used as a mole ratio
The ratio comes from the balanced equation. Dividing two masses by each other, with no molar mass, is not an amount of substance.
3. A missing unit or a volume left unconverted
A bare number is not a result. A volume in the wrong unit makes the rest of a correct method give a wrong quantity. Convert first, then substitute.
4. A definition where a calculation was asked
Explaining what a mole is does not answer a question that asked you to find a mass. Do the arithmetic, and define the term only when the command says define.
5. An inference with no observation
In qualitative work, the observation and the inference are separate. Naming a salt you did not earn from an observation does not score the observation mark.
6. Rounding in the middle
Rounding each line, then using that rounded value, makes the last line hard to follow. Keep the digits until the end, then round as the question asks.
Keep these open while you revise
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Practise with Kevin and Anna