Chemistry

    AQA
    A-Level

    Specification: 7405

    Chemistry explores the building blocks of our world - from atoms to complex compounds. You'll learn about atomic structure, bonding, reactions and energy changes, developing practical skills alongside theoretical understanding.

    5

    Topics

    0

    Objectives

    17

    Exam Tips

    20

    Pitfalls

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    Key Features

    • Master chemical calculations
    • Conduct required practicals safely
    • Understand organic chemistry
    • Analyse rates and equilibria

    Assessment Objectives

    AO1
    35%-40%

    Demonstrate knowledge and understanding of scientific ideas, processes, techniques and procedures

    AO2
    40%-45%

    Apply knowledge and understanding of scientific ideas, processes, techniques and procedures: in a theoretical context, in a practical context, when handling qualitative data, when handling quantitative data

    AO3
    28%-30%

    Analyse, interpret and evaluate scientific information, ideas and evidence, including in relation to issues, to: make judgements and reach conclusions, develop and refine practical design and procedures

    What Gets Top Grades

    A*/Grade 9

    Knowledge & Understanding

    Demonstrates comprehensive and accurate knowledge

    • Uses correct subject-specific terminology
    • Shows detailed understanding of concepts
    • Makes accurate connections between topics
    • Demonstrates depth beyond surface-level knowledge

    Application

    Applies knowledge effectively to new contexts

    • Selects relevant knowledge for the question
    • Adapts understanding to unfamiliar scenarios
    • Uses examples appropriately
    • Shows awareness of context

    Analysis & Evaluation

    Develops sophisticated analytical arguments

    • Constructs logical chains of reasoning
    • Considers multiple perspectives
    • Weighs evidence to reach justified conclusions
    • Acknowledges limitations and nuances

    Key Command Words

    AQA
    State
    1 mark

    Give a single fact or term

    Identify
    1 mark

    Name, select, or recognise

    Outline
    2 marks

    Set out main features briefly

    Describe
    2-4 marks

    Give an account of what something is like or what happens

    Explain
    3-6 marks

    Give reasons with developed cause→effect chains

    Compare
    2-4 marks

    State similarities AND differences (both required)

    Analyse
    6-9 marks

    Examine in detail showing cause→effect→consequence chains

    Evaluate
    6-12 marks

    Weigh up BOTH sides, reach JUSTIFIED conclusion

    Assess
    6-12 marks

    Make judgments about importance with justification

    Calculate
    2-4 marks

    Show formula→substitution→calculation→answer with units

    Common Exam Mistakes

    Pitfalls to avoid in your exams

    • •Failure to convert mass into kilograms (kg) when using the kinetic energy equation KE = 0.5mv^2, resulting in calculation errors by orders of magnitude
    • •Removing electrons from the 3d sub-shell before the 4s sub-shell when writing electron configurations for transition metal ions
    • •Omitting state symbols (g) or using incorrect species (molecules instead of atoms) when writing equations for first ionisation energy
    • •Confusing the fragmentation pattern seen in electron impact ionisation with the 'soft' ionisation of electrospray
    • •Confusing the mechanism of separation: stating 'solubility' for TLC (which is adsorption) or 'adsorption' for GC (which is partition)
    • •Measuring the solvent front distance from the bottom of the plate instead of from the pencil baseline (origin)
    • •Failing to explain that the solvent level must be below the baseline to prevent spots from dissolving into the reservoir immediately
    • •Stating that GC identifies substances solely by retention time without acknowledging the need for external calibration standards or MS data

    Top Examiner Tips

    Expert advice for exam success

    • •In TOF calculations, explicitly write out the conversion of mass: Mass of one ion (kg) = (Mr / 6.022x10^23) / 1000
    • •When explaining trends in ionisation energy, always structure your answer around three factors: Nuclear Charge, Distance/Shielding, and Attraction
    • •Memorise the specific definition of 'Relative Atomic Mass' verbatim; AQA examiners penalise missing references to 'weighted mean' or 'carbon-12'
    • •Check the ionisation method specified in the question: if Electrospray is used, the peak is at Mr + 1
    • •In 6-mark practical descriptions, explicitly mention drawing the baseline in pencil to prevent ink contamination affecting results
    • •When comparing substances in GC, link shorter retention times to lower solubility in the stationary phase and higher volatility
    • •Always check the polarity of the solvent and stationary phase; polar components retain longer on polar stationary phases due to stronger intermolecular forces
    • •For GC-MS questions, clearly distinguish that GC separates the components while MS identifies them via m/z ratios

    Specification Topics

    5 topics

    Atomic Structure

    0 objectives4 tips4 pitfalls

    Chromatography

    0 objectives4 tips4 pitfalls

    Alkanes

    0 objectives3 tips4 pitfalls

    Alkenes

    0 objectives3 tips4 pitfalls

    Alcohols

    0 objectives3 tips4 pitfalls

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