• Unsurprisingly, multistep calculations are most often cited as difficult, particularly those relating to amount of substance, acids, bases and buffers, and thermodynamics.
• Examiner’s often report that “only the best” A-Level chemistry students scored full marks on 6-mark level of response questions, reflecting their difficulty.
• K_p calculations provide a greater challenge than K_c, especially when mole fractions and partial pressures are required.
• Halogen redox chemistry, a problem at AS level, continues to cause difficulties at A-Level.
• Transition metals is a problematic topic for many students, who find it difficult to contend with its formulae, equations, and advanced concepts.
• Understanding, and writing equations for, the redox chemistry of cells and fuel cells is a challenging area.

Contents

A lot of my students hate Paper 1 and its focus on inorganic and physical chemistry (as opposed to merely disliking papers 2 and 3).

It’s not hard to see why.

The physical chemistry topics (like acids, bases and buffers) are full of complex calculations that can even be a problem for strong mathematicians. Paper 1 also examines some of the hardest A-Level chemistry concepts to understand, and has tons of content to memorise that isn’t exactly very memorable. Who doesn’t love the random behaviour of the different transition metals, with all their different colours, complexes, and equations?

If you’re aiming for a top grade though, you have to meet the challenge of paper 1 head-on.

To help you do this, I have listed all the difficult paper 1 questions (according to examiner reports), and summarised the most frequently occurring areas of difficulty. These are your priority topics to understand and practise when studying:

Please do check out my guide to the difficult AS questions on papers 1 and 2 here.

Here are the hardest topics, based on their appearance in examiner reports:

Amount of substance

• Unstructured, multistep titration and back-titration calculations.
• Writing and balancing chemical equations for unfamiliar reactions (particularly those described in words).
• Unstructured, multistep ideal gas equation calculations.

Atomic structure

• TOF-MS calculations, particularly involving rearranging equations.
• Calculating isotopic abundances from RAM (especially involving algebra).
• Describing the operation of the TOF mass spectrometer (particularly ionisation methods and determination of abundances).
• Giving accurate definitions for key terms (e.g. RAM).

Acids and bases

• Calculating the pH of buffers.
• Calculating quantities needed to prepare a buffer of a given pH.
• Using K_w to calculate pH of strong bases.
• Relating pH and solubility.
• Calculating the pH of a solution after partial neutralisation.
• Understanding and applying extension concepts such as half-equivalence points.
• Calculating the pH of solutions after dilution.
• Understanding the logarithmic nature of the pH scale and how small quantities of acid/alkali produce large pH changes.

Bonding and structure

• Drawing displayed formula for unfamiliar covalent molecules and ions.
• The polarising ability of some ions.
• Drawing diagrams to show hydrogen bonds for unfamiliar molecules.
• The common AS misconception that covalent bonds are broken during melting and boiling is still present at A-Level.

Electrode potentials

• Comparing oxidising/reducing agent ability based on standard electrode potentials
• The chemistry of fuel cells, particularly half-equations for unfamiliar fuel cells.
• Predicting or explaining reactions based on standard electrode potentials
• The electrode reactions in a lithium-ion cell.
• Deducing electrode half-equations from complete redox equations.

Equilibrium

• Deducing or explaining optimal reaction conditions based on data and reaction characteristics.
• K_p calculations and working out partial pressures from equilibrium data.

Inorganic chemistry

• Writing redox reactions for reactions of halogens and halide ions.
• Solubility of group 2 compounds.

Qualitative analysis

• Precipitation reactions for metal ions, particularly those based on solubility.
• Test-tube reactions to identify or distinguish metal ions.

Redox titrations

• Multistep, unstructured redox titration calculations based on practical data .

Thermodynamics

• Understanding how temperature affects Gibbs energy and feasibility.
• Graphical representations of the Gibbs energy equation.
• Using Born-Haber cycles to calculate quantities other than lattice enthalpy.
• Experimental vs. theoretical lattice enthalpy (perfect ionic model).
• Explaining trends in lattice enthalpy and hydration enthalpy.
• Writing equations for standard enthalpy changes of specific substances.

Transition metals

• Homogeneous catalysis.
• Catalysis of the peroxodisulfate-iodide reaction.
• Recalling equations for aqueous chemistry.
• Stereoisomerism in complex ions.
• Writing formulae for complex ions.
• Explaining the origin of colour (and lack of colour) for transition metals.
• ‘Flowchart’ questions, requiring you to work out colour and formulae of complexes, and reagents required.
• Explaining/comparing the acidity of metal aqua ions.

Navigating through multistep calculations in A-Level Chemistry can be daunting, but it’s a skill you can master with the right approach. One of the most important things is to remember that complex calculations are not just about numbers, it’s also about understanding the logic behind each step.

Here’s how you can become more proficient in handling these challenges:

Understand the Logic

Start by understanding the ‘why’ behind each calculation. This means looking at each step not just as a number to crunch but as a part of a larger process. Knowing the reason for each step helps in retaining the method and applying it correctly. This is especially important with calculations that use experimental data. It’s really important to connect the data with the steps in the right way, otherwise you can start mixing and matching numbers with the wrong substances (for example, inadvertently combining a volume for one solution with the concentration of another).

Break Down the Problem

When faced with a complex problem, divide it into smaller sections. Tackle each section one at a time. This approach makes the problem more manageable and less overwhelming.

Diversify Your Practise

Regular practise is essential, but it’s important to vary the types of problems you work on. This ensures you are prepared for different scenarios and helps reinforce your understanding of the underlying concepts.

Develop a Methodical Approach

Create a systematic method for approaching common types of problems. This could be a checklist, or a set of steps that you follow. Having a consistent approach can be a reliable tool during exams.

For example, the steps required to solve acid-base titrations and redox titrations are largely the same, and the majority of calculations have many steps in common. Having a checklist that instructs you what to do at each step of the calculation can be very effective (though bear in mind, this won’t help with the hardest calculations that will require you to come up with an original solution).

Learn from Your Mistakes

Reviewing and understanding your mistakes is the most important part of studying.

Take time to analyse where you went wrong and why. This reflection is key to improving your problem-solving skills.

It’s about building a strong foundation in understanding the concepts and practicing systematically. With time and effort, you’ll gain confidence and proficiency in handling the complex paper 1 chemistry calculations that students often dread.

If you’re struggling to keep track of all the factual content needed for paper 1, you’re not alone.

Inorganic chemistry is full of equations, reagents and reactivity trends. This knowledge must be committed to memory before it can be applied in questions.

Here are some effective ways to embed this information in your memory:

The Magic of Mind Maps

Mind maps are a game-changer for memorising connected concepts in chemistry. Start with a central concept and branch out to related topics, creating a visual web of information. This method helps in organising and connecting different pieces of information, making it easier to recall them during exams.

It works especially well for transition metals aqueous chemistry, to show the reaction pathways that connect different complex ions.

Flashcards: Your Portable Study Aids

Flashcards are a classic for a reason. They’re simple, versatile, and effective.

Write a key term or concept on one side and its explanation or definition on the other. Regularly reviewing these cards helps reinforce your memory and makes revision more interactive.

Some students like to make flashcards for common calculations. On one side, they write the question, on the other, they show the model answer, together with the relevant mathematical equation. This can also help you to get quicker at selecting the right approach for a given calculation, which is important when you’re up against the clock in the exam.

Regular Review Sessions

The key to memorisation is repeatedly and actively recalling information (aka active recall). Schedule regular sessions to go over your mind maps and flashcards. Use your mind maps and flashcards when answering past paper questions.

This consistent review helps transfer information from short-term to long-term memory, making recall easier during exams.

Teach What You Learn

One of the best ways to solidify your understanding of a concept is to explain it to someone else. Teaching forces you to organize your thoughts and explain concepts clearly, which in turn strengthens your own understanding and memory.

Connect New Information with What You Already Know

Linking new concepts to things you already understand can make them easier to remember. Try to find connections between new information and your existing knowledge. This creates a stronger mental association and aids in recall.

By incorporating these techniques into your study routine, memorising the huge amount of content needed for paper 1 becomes less daunting.

Remember though, effective memorisation is not about cramming; it’s about creating a structured and interactive way to engage with the material. With these methods, you’ll be well on your way to mastering the factual side of chemistry.

And please, do your poor teacher a favour and follow their advice: LEARN DEFINITIONS! A surprising number of discriminating questions on paper 1 simply tested straightforward recall of key definitions. You don’t want to be throwing away marks due to not memorising things.

Ever wondered how some students seem to have an effortless grasp of A-Level Chemistry?

I’m willing to bet that one of their secrets is they’ve spent time mastering the core skills. While others are struggling to remember mathematical formulae, or how to balance redox half-equations, they’re putting the finishes touches on their answer.

Here’s how you can build and refine these essential skills:

Consistent Practice

Consistency is key in mastering any skill.

Set aside regular time for practicing core chemistry skills. This could be solving equations, balancing reactions, or working through titration problems. The more you practice, the more natural these skills become. You’re aiming for fluency, so that the skills become almost automatic.

Focus on Understanding, Not Just Doing

When practicing, focus on understanding the ‘why’ behind each step. Don’t just go through the motions. Ask yourself why a particular reaction happens or why a certain rule applies. This deeper understanding will make your skills more adaptable.

Use a Variety of Resources

Don’t limit yourself to just textbooks.

Use a mix of resources like YouTube videos, websites, blogs, online tutorials, and interactive simulations. Different resources can offer new perspectives and explanations, helping to reinforce your understanding.

Apply Skills in New Contexts

Try applying your chemistry skills to new and different problems. This could mean tackling problems that are not directly from your textbook or syllabus. Applying skills in varied contexts helps to deepen your understanding and flexibility.

Get Feedback

Feedback is crucial for improvement. Work with teachers, tutors, or study groups to get feedback on your problem-solving approach. Understanding where you can improve helps you refine your skills more effectively.

Reflect on Your Learning

Take time to reflect on what you’ve learned and how you’ve applied your skills.

Reflective learning helps you understand your strengths and areas for improvement, guiding your future study sessions. By focusing on these strategies, you’ll develop a strong command of the core skills needed for paper 1.

Mastering the hardest questions from AQA A-Level Chemistry paper 1 is about more than just memorising facts and formulae.

It involves developing a deep understanding of concepts, refining problem-solving skills, and effectively memorising facts.

By embracing the strategies we’ve discussed — breaking down complex calculations, using mind maps and flashcards for memorisation, and consistently practicing core skills — you’re setting yourself up for success.

How have these strategies worked in your study routine? Do you have any tips or experiences you’d like to share with fellow students? Drop a comment below and let’s continue the conversation!