Your child has studied the Chemistry notes. They can define a catalyst, name common gases and describe factors that affect a reaction.
Then a test question presents an experiment they have never seen before.
There is a table of results. The question asks them to explain a difference between two reactions. Your child reads it twice, writes one sentence and loses marks.
For parents of IGCSE students in Nigeria, this is frustrating. You can see that your child has revised. Why does that knowledge disappear when the question changes?
Often, the knowledge has not disappeared. The learner needs help connecting a familiar Chemistry idea to new information, then explaining that connection clearly.
The way forward is to examine where that process breaks down.
Knowing a Fact and Using It Are Different Skills
Consider a learner who knows this fact:
A greater surface area can increase the rate of a reaction.
They might answer that question correctly when it appears under the heading “Factors Affecting Reaction Rates.”
But an examination question might describe two experiments using the same mass of calcium carbonate: one uses large pieces and the other uses powder. The learner must recognise that powder exposes more surface area, connect that to the rate of reaction, and use the question’s results to support the answer.
That requires more than recalling a sentence. It involves reading the situation, choosing the relevant idea and explaining why it applies.
Cambridge IGCSE Chemistry, for example, includes fundamental concepts, applications and practical skills. Ask your child’s school whether they follow Cambridge, Pearson Edexcel or another qualification so that revision uses the correct syllabus and question types.
A Worked Example: What Is the Question Really Testing?
Here is an illustrative practice question, not a past-paper question.
A student reacts 5 g of calcium carbonate powder with an excess of dilute acid. They repeat the experiment using 5 g of calcium carbonate in large pieces. The acid concentration and temperature stay the same.
After 30 seconds, the powder has produced 24 cm³ of carbon dioxide. The large pieces have produced 10 cm³.
Explain why the powder produces carbon dioxide faster at the start.
A weak answer might say:
“Powder reacts faster.”
That repeats the observation. It does not explain it.
A stronger answer is:
“The powder has a larger surface area exposed to the acid. This allows more frequent successful collisions between reacting particles, so carbon dioxide is produced faster at the start.”
Notice the chain of reasoning:
What changed? The size of the calcium carbonate pieces.
What does that change affect? The surface area exposed to the acid.
How does that affect the reaction? It allows more frequent successful collisions.
What result does the question show? More carbon dioxide was collected from the powder after 30 seconds.
Your child may remember the phrase larger surface area but leave out its connection to the faster reaction. Or they may explain the theory but never refer to the results. Reviewing the missing link is more productive than telling them to read the entire chapter again.
Use Three Questions to Find the Gap
When your child misses an application question, ask:
1. “What information does the question give you?”
Can they identify what was changed, what was measured and what stayed the same? In the example above, the particle size changed; the amount of gas produced over time was measured.
If the child cannot describe the experiment in plain language, begin there. A long question can be difficult to process even when the Chemistry concept is familiar.
2. “Which Chemistry idea might explain the result?”
Do not tell them the topic immediately. Give them time to connect the situation to something they have studied.
If they identify surface area after a small hint, they may mainly need practice recognising the idea in unfamiliar contexts. If they cannot explain surface area even when it is named, revisit the concept itself.
3. “How does that idea explain these results?”
Ask them to make a complete connection between the scientific idea and the observation. This is often where an answer becomes too brief.
Your child should be able to say more than “because of surface area.” They need to explain what the greater surface area changes and how that leads to the result described.
Four Reasons Students Lose Marks on Application Questions
They misread the experiment
A learner may overlook that the acid is in excess, or that both experiments used the same mass of calcium carbonate. They then explain a difference that the question has already controlled.
Ask them to underline the variable that changed and circle the conditions kept the same.
They recognise a keyword and rush to an answer
The word powder may remind the student of reaction rates, but they still need to read what the question actually asks. Does it ask about the initial rate, the total amount of product, or how to make the comparison fair?
Those are different questions.
They know the idea but omit the reasoning
The learner writes “more collisions” without explaining why the collisions occur more often, or states “higher rate” without linking it to the collected gas.
Practise building an answer in a logical sequence: change → scientific reason → observed result.
They struggle to interpret tables or graphs
A student may understand the topic verbally but find it hard to read values, compare trends or distinguish a faster reaction from a greater final amount of product.
Give them time to describe what the data shows before asking for an explanation.
How Parents Can Review a Marked Chemistry Paper
You do not need to know every answer yourself. Sit with your child and their teacher’s feedback or the correct mark scheme for the paper. Choose three missed questions.
For each, record the main difficulty:
DifficultyWhat to ask your childMissing knowledge“Can you explain the underlying concept without looking at the notes?”Misreading“Which detail in the question did you miss?”Choosing the wrong idea“What did the question change or measure?”Incomplete explanation“How does your Chemistry idea cause the result?”Data interpretation“What does each column or axis represent?”
Then ask your child to answer a different question testing the same skill. Correcting the original answer is a start; applying the idea again shows whether they have learned from it.
If several errors share the same cause, tell the teacher or tutor. “My child can recall reaction-rate factors but struggles to use experimental results in explanations” is a useful description of the problem.
Should Your Child Do More Past Papers?
Yes, at the appropriate stage—but doing more papers alone will not necessarily solve an application gap.
Try this sequence:
- Review the concept until your child can explain it in their own words.
- Work through one question together, discussing what changed and what was measured.
- Let your child attempt a new question independently.
- Review the reasoning, not just the final sentence.
- Return to the skill later to see whether it still holds.
Use papers and materials that match the qualification your child is taking. Cambridge notes that some older past papers may not reflect the content of the current syllabus, so confirm suitability with the school when selecting practice.
What About Practical Chemistry Questions?
A child may be able to describe an experiment they performed in class but become unsure when an examination describes a different setup.
Help them develop a routine:
- What is the purpose of the experiment?
- What is being changed?
- What is being measured?
- Which conditions must remain the same?
- What do the results show?
- Is the conclusion supported by the data?
These questions encourage the learner to think through the investigation instead of searching their memory for a paragraph to copy.
If your child has had limited experience interpreting practical work, raise this with the school. Ask what practical activities and assessment preparation are planned for their course.
When Can One-to-One Chemistry Support Help?
Consider extra support if your child repeatedly knows the notes but cannot answer new questions, or if low marks appear mainly in explanations, data interpretation or practical work.
A useful tutor should inspect the child’s actual answers and separate content gaps from application gaps. The learning goal might be:
“Read an unfamiliar reaction-rate experiment, identify the variable, interpret the results and write a complete explanation using the relevant Chemistry concept.”
You can then check progress with a new question, rather than relying on whether the learner remembers a worked example.
IGCSE Chemistry Support in Nigeria
Glareminds provides one-to-one online academic support for learners studying international curricula in Nigeria, including IGCSE Chemistry. We can review a learner’s schoolwork, identify the questions they find difficult and build focused lessons that develop both understanding and independent problem solving.
If your child attends a British or international school in Lagos, Abuja, Port Harcourt or elsewhere in Nigeria, book an academic consultation with Glareminds. Bring a recent marked Chemistry test or a few questions your child could not answer. That gives us a concrete place to begin.
Book an academic consultation with Glareminds
Frequently Asked Questions
Why can my child define Chemistry terms but not answer exam questions?
They may know a fact but struggle to recognise when it applies, interpret new information or explain the link between an idea and a result. Review their written answers to locate the specific difficulty.
Should my child memorise mark schemes?
Mark schemes can show what a question rewards, but memorising one answer is unlikely to prepare a learner for every new situation. Practise explaining the underlying idea in different contexts.
Are practical questions important in IGCSE Chemistry?
Yes, practical and investigative skills are part of Cambridge IGCSE Chemistry. Confirm the precise requirements and assessment format for your child’s qualification with their school.
How can I tell whether tutoring is working?
Give your child an unfamiliar question from a topic they have studied. Check whether they can identify the relevant Chemistry idea, use the information provided and explain the result with less help.