5 Tips for Smashing the GCSE Chemistry Exams

GCSE Chemistry is notorious for its tough 6-markers, tricky calculations, and picky mark schemes. However, with the right techniques and mindset, you can achieve excellent results.

As a current medical student who’s been tutoring GCSE Chemistry for over three years, I’ve solidified the perfect revision strategy for those wanting to walk into their exams with confidence that they can beat those daunting mark schemes.

1. Learn the Exam Command Words

A commonly reported theme in GCSE Chemistry exam reports is that students do not understand the exam keywords! Or they rush to answer the question in a way the examiner is not looking for...

Your answers need to be specifically tailored to what the question is asking you to secure top marks, and you should be confident in the difference between the command words so that you can concisely answer questions and tick off the marking points. 

Here is a table summarising the most common ones, as well as my top tips for each one. Real past exam questions have been used as examples to illustrate each point.

Command Word: Name, Give or State

Meaning

Just recall a simple piece of knowledge!

Typically low tariff questions so don’t waste time writing out too much detail.

Example Question and Model Answer

Q: Name the compound formed when cobalt reacts with oxygen. [1 mark]

A: Cobalt oxide [1 mark]

Command Word: Describe

Meaning

Link together a series of facts in a logical order. Don’t waste time explaining why the process happens, just write out the steps of it.

When used for questions with a graph or other figures, you have to only say what you see using the information provided. Don’t waste time using your chemistry knowledge about what it means and its causes or effects - that is for more of an “explain” scenario.

Example Question and Model Answer

Q: Describe the formation of polypeptides. [2 marks]

A:

• Amino acids have two different functional groups; [1 mark] 
• Which react by condensation polymerisation to form polypeptides [1 mark]

Command Word: Suggest

Meaning

Students often skip this thinking “I’ve not been taught this!”, but remember these questions are normally higher marks because they require you to apply your prior knowledge to a new situation, testing your understanding.

Example Question and Model Answer

Q: Short-chain fractions have low supply and high market demand. Suggest three ways in which the oil industry could overcome this problem. [3 marks]

A: 

• Develop a market for low-demand fractions; [1 mark]
• Crack long chain hydrocarbons: [1 mark]
• Convert low-demand fractions to high-demand fractions or bigger molecules to smaller molecules; [1 mark]

Command Word: Explain

Meaning

Say why or how something takes place. You should link descriptions to a deeper explanation of the reasons behind why it happens. 

Example Question and Model Answer

Q: Explain why diamond has a higher melting and boiling point than carbon dioxide. [3 marks]

A: Diamond has a higher melting/boiling point because:

• Diamond has strong covalent bonds; [1 mark]
• Carbon dioxide has weak intermolecular forces; [1 mark]
• These need less energy to overcome than covalent bonds; [1 mark]

Command Word: Discuss

Meaning

‘Discuss’ can either ask you to compare some factors and then explain them, or they can be more similar to ‘describe’ questions where they ask you to consider different parts of a topic. They typically need you to follow a strong chain of reasoning and sometimes need a concluding statement.

Example Question and Model Answer

Q: Discuss the difference in pH between a weak acid and a strong acid of the same concentration

A: The difference in pH between a weak acid and a strong acid of the same concentration is:

• The pH of a weak acid is higher than the pH of a strong acid; [1 mark] 

   OR

   The pH of a strong acid is lower than the pH of a weak acid; [1 mark] 

Explanation:

• Strong acids dissociate completely in aqueous solutions; [1 mark]  
• Weak acids only partially dissociate; [1 mark]
• Therefore, weak acids produce fewer H+ ions in solution than strong acids; [1 mark]
• Because a lower number of acid molecules dissociate; [1 mark] 

Command Word: Evaluate

Meaning

Use the available evidence and your pre-existing knowledge to make a judgement and justify your answer. This is similar to a “discuss” question but you normally need a proper conclusion with these questions. Typical pitfalls where students drop marks are not including an argument from both sides.

Example Question and Model Answer

Q: Evaluate the production and use of plastic bottles and glass bottles using Table 1 [6 marks]

A: Crude oil is used to make plastic bottles which is a non-renewable resource, whereas soda lime glass is made from limestone, sand and salt. They are therefore both produced from limited raw materials but a higher percentage of recycled materials are used in glass so raw materials are conserved.

There are 2 stages of production to make soda-lime glass, with the second stage involving heating the sand, limestone and sodium carbonate. However, there are 3 stages in the production of the plastic bottle. The second stage would involve cracking of naphtha to obtain ethene and the third stage would involve polymerisation of ethene. The production of plastic may therefore be slower as there are more stages. 

A glass bottle can be reused and other glass products can be produced from recycled glass, but to reuse them they need collecting and cleaning. Plastic has a range of sizes compared to glass.

Overall I believe glass bottles have more pros compared to plastic bottles because they can be reused, conserve more raw materials, and have fewer stages in their production compared to plastic bottle production.

Command Word: Compare

Meaning

Make sure to give BOTH similarities and differences between the things you are comparing. 

Example Question and Model Answer

Q: Compare the structures and reactions of propene with propane. [6 marks]

A: With regards to structure and bonding, both are hydrocarbons with three carbon atoms per molecule. Both have covalent bonds and are small molecules. However, propane contains 8 H atoms per molecule whereas propene contains 6. Also, propane contains single C-C bonds only whereas propene contains a double bond.

With regards to their reactions, both react with oxygen in complete combustion reactions to produce water and carbon dioxide. Both also react with oxygen in incomplete combustion reactions to produce water, carbon monoxide and carbon.

However, propene decolourises bromine water whereas propane does not. Also, propene is more reactive than propane and can undergo additional reactions that propane cannot. 

Source for questions: AQA 



2. Get up to Scratch With Your Required Practicals

There are plenty of videos online detailing how to do all of the required practicals. Here is a useful link to a summary video for all of them in one place. 

Malmesbury Science is a great channel for concisely demonstrating each required practical too if you’re looking for more detail.

When it comes to revision, make sure you get a clear understanding of the apparatus and techniques used for each one, as well as the strengths and limitations of the equipment. For example, we’d use a Bunsen burner to bring liquids to a boil, but a water bath to maintain them at a constant temperature. 

Additionally, make sure you’re confident about the independent, dependent and control variables for each practical. It’s very commonly asked to suggest potential control variables for a practical. As always, supplement this with plenty of exam questions so you can practise applying your knowledge. 

In my experience, the identifying ions practical and the electrolysis practical are the most poorly understood by students, so perhaps these might be ones to pay particular attention to!

3. Calculation Questions

Students often are unsure how to go about complex calculation questions. Ask yourself “what information do I need to know to work out what the question wants from me?”. 

I find that tables are a great way to organise information and figure out what info is missing. There are plenty of exam practice run-throughs on YouTube and worksheets from MME Revise for example. Balancing equations is also an important skill that can come up on every paper - so make it a priority to get confident with these!

Also, be sure that you’re confident with your unit conversions. Common conversions you’ll need are displayed below:

Source: BBC bitesize 

4. Come up With Memory Aids

There’s a lot of specific facts that you need to remember for GCSE Chemistry, so you can use techniques such as word association to ensure you don’t forget! For example, I remember that cations are positive because I like cats (so I think positively of them). 

You could also use acronyms such as ‘OIL RIG’ which stands for “oxidation is lost, reduction is gained” in terms of electrons.

Mnemonics are also a favourite for me - I use “Lazy Penguins Keep Drinking Hot Beer” to remember the fractions of fractional distillation which stands for “liquified petroleum gas, petrol, kerosene, diesel, heavy fuel oil, bitumen”. 

A lot of people also use the technique of creating “memory palaces” for small facts. Write a fact on a post-it note and stick it in an area you’re likely to look at every day such as the fridge or your bedroom mirror. This works because you’ll start to associate that fact with that area in your house, compounding it in your memory.

5. Being intentional with your time. 

The highest-scoring Chemistry students will revise little and often. You need to employ spaced repetition in your revision, which is where you repeat looking at content in systematic intervals. Check out point 4 in this blog on the most effective revision tips - backed up by science!

You will review newer, more difficult concepts more frequently than ones you understand better. You can use flashcard apps like anki to do this automatically for you.

In terms of when you revise, try to work out what time of day your mind is most fresh and make it a routine to revise intensely during those hours, rather than doing long sessions of unfocused work during the day. 

Likewise, during the hours of the day when you feel a little sluggish (this was always right after lunch or after just coming home from school for me!) intentionally keep that time as breaks to do what you enjoy - whether that’s going to the gym, seeing your friends or just winding down with some Netflix. 

Don’t feel guilty for setting time to take off as it will make you more productive in the long run…as long as you don’t get too comfortable!