Hard A-Level Chemistry Questions:
AQA AS Paper 1 and 2
This guide is part of a series on difficult AQA AS/A-Level chemistry questions.
- The guide to Paper 1 (inorganic and physical chemistry) is here
- The guide to Paper 2 (organic and physical chemistry) is here
- The guide to Paper 3 is here
Key Points:
- Amount of substance calculations account for a high proportion (33%) of difficult questions
- Questions on practical chemistry consistently pose a significant challenge
- Novel questions not seen on previous papers are a common source of difficulty
- 6-mark level of response questions are frequently among the hardest questions on AS exam papers
The Importance of Hard Questions in Exam Preparation
“Read examiner reports” is standard advice in online guides about mastering A-Level chemistry, including mine here.
Why should you read examiner reports? First, they tell you what students did well in the exam. Second, they tell you what things students did badly. And last of all, they tell you which questions caused students problems, and why.
If you’re aiming to master AQA A-Level chemistry, this is all valuable information for you.
Knowing common exam mistakes are obviously things you want to avoid. Difficult questions extend your understanding and improve your analytical skills, making them vital preparation for the exam. Topics that are repeatedly identified as problem areas are ones you want to prioritise when studying.
In this article, I’ve analysed the available examiner reports for AQA AS chemistry and listed the questions that were described in various ways as difficult. These are typically questions with a low success rate (i.e. a small percentage of students got them right).
If you’re an AQA student wanting to test your knowledge against the hardest AS questions, this article is for you.
You can use this article in several ways:
- Use it to find and attempt all the difficult questions on a given topic
- Use it to structure your revision – devote extra time to mastering the difficult topics that I’ve listed
- Use it to find all the hard questions in each AS paper so that you use them to extend your knowledge and skills
Not studying AQA A-Level chemistry? Comment below if you’d like to see a similar article for CAIE, Edexcel, or OCR A-Level chemistry.
Recurring Topics That Students Found Difficult
These are the topics that tend to come up repeatedly in the hardest AS questions:
Amount of Substance Calculations
- Multistep calculations, especially those involving the ideal gas equation.
- Practical data-based calculations, novel problems not seen in previous papers, and limiting reactants.
- Calculations involving density, non-standard units, and either very large or very small quantities.
- The use of algebra in various calculations and the application of Avogadro’s constant.
- Writing ionic equations and half-equations.
Atomic Structure
- Transition metal ions and their electron configurations.
- The principles of Time-of-Flight (TOF) mass spectrometry and predicting mass spectra, especially m/z peak ratios.
- Multistep TOF mass spectrometry calculations.
Bonding & Structure
- Intermolecular forces, in particular, relating intermolecular forces to physical properties, such as melting and boiling points.
- The common misconception that melting or boiling simple covalent substances involves breaking covalent bonds was frequently seen.
- Determining the shapes of unfamiliar molecules and ions.
Equilibrium
- Calculation of moles at equilibrium from Kc.
- The effects of temperature on equilibrium position and yield.
- Understanding compromise conditions in industrial processes.
Group 17 Halogens
- The redox chemistry of halide ions with concentrated sulfuric acid.
- The ability to write redox equations or half-equations for halogen chemistry.
Organic Chemistry
- Understanding mechanisms involving unsymmetrical alkenes and cyclic molecules.
- Interpreting skeletal formulae.
- Deducing the identity and number of isomers from molecular formulae
- Drawing repeating units and monomers in polymers.
Practical Chemistry
- A clear understanding of apparatus and their purposes, practical techniques, and the principles behind certain techniques was often found lacking.
- Accurately describing experimental procedures.
- Suggesting improvements to experiments.
- Selecting the most appropriate technique for a given practical requirement.
Qualitative Analysis
- Identifying or distinguishing organic functional groups using tests.
- Tests for ions and gases to distinguish/identify substances.
Redox
- Writing balanced redox equations and deducing half-equations.
Level of Response Questions
- These 6-mark questions demand a well-structured and reasoned answer, encompassing multiple marking points. They have been significant discriminators in all AQA AS exams.
