AQA A-Level · 考試技巧

Chemistry 7405 考試技巧

Master AQA A Level Chemistry (7405) with this examiner-backed study package. Grounded in insights from the 2022-2024 papers, this guide covers exact timing strategies, strict mark-scheme expectations for mechanisms and calculation units, key inorganic observations, and high-yield calculator techniques to secure your target grade.

閱讀時間 4 分鐘更新於: 2026年6月21日

試卷概覽

卷數
3
總分
300
考試時間
6小時
題型
4
試卷時間分數題數比重題型
Inorganic and Physical Chemistry2小時105935%Structured Explanation, Theory, and Calculations
Organic and Physical Chemistry2小時1051135%Structured Explanation, Mechanism Drawing, and Calculations
Synoptic2小時903530%Structured Practical and Synoptic Questions, 選擇題
評級
A*ABCDEU
計算機規定

A scientific or graphical calculator that meets JCQ regulations may be used (some GCSE Mathematics and Science papers are non-calculator). Graphical calculators must be set to exam mode; you must clear any stored programs, notes or data before the exam, and the calculator must not be able to retrieve stored text or formulae.

  • AO1: AO1: Knowledge and understanding of scientific ideas, processes, techniques and procedures. (35%)
  • AO2: AO2: Apply knowledge and understanding of scientific ideas, processes, techniques and procedures. (40%)
  • AO3: AO3: Analyse, interpret and evaluate scientific information, ideas and evidence. (25%)

根據歷屆試題與評分準則整理(2022–2024)。

計算機程式

Graph: zeros, intersections & turning points

Graphical calculator / GDC (exam mode)

用途: Plot a function to read its roots (zeros), points of intersection, and maxima/minima.

使用時機: Checking solutions, sketching, or solving where an analytic method is hard.

步驟
Graph the function(s) and use the built-in zero, intersect and maximum/minimum tools.

考試提示: Allowed under JCQ rules, but you must still show your method — an unsupported calculator answer earns no method marks. Clear all stored programs, notes and data (graphical calculators in exam mode) before the exam.

Numerical equation solver

Graphical calculator / GDC (exam mode)

用途: Solve an equation or find a variable numerically when an algebraic route is long or implicit.

使用時機: Iterative or implicit equations, or to confirm an algebraic solution.

步驟
Use the equation/zero solver, entering the equation and a sensible starting estimate.

考試提示: Allowed under JCQ rules, but you must still show your method — an unsupported calculator answer earns no method marks. Clear all stored programs, notes and data (graphical calculators in exam mode) before the exam.

Numerical integration & differentiation

Graphical calculator / GDC (exam mode)

用途: Evaluate a definite integral \(\int_a^b f(x)\,dx\) or a gradient \(f'(x)\) at a point.

使用時機: Checking calculus answers, or where only a numerical value is needed.

步驟
Use the GDC's numeric integral / derivative function with the limits or the point.

考試提示: Allowed under JCQ rules, but you must still show your method — an unsupported calculator answer earns no method marks. Clear all stored programs, notes and data (graphical calculators in exam mode) before the exam.

Statistics & probability distributions

Graphical calculator / GDC (exam mode)

用途: 1-var/2-var statistics, linear regression, and cumulative binomial / normal / Poisson probabilities without tables.

使用時機: Statistics questions and hypothesis tests.

步驟
Enter data in the statistics editor, or use the distribution menu (binomial cdf, normal cdf, …).

考試提示: Allowed under JCQ rules, but you must still show your method — an unsupported calculator answer earns no method marks. Clear all stored programs, notes and data (graphical calculators in exam mode) before the exam.

常見錯誤

  1. 1high涉及分數: 2Chemical equilibria, Le Chatelier’s principle and Kc

    Failing to convert volume from cm³ to dm³ in Kc and Ka calculations, or forgetting to square terms in the rearrangement of rate equations.

    如何避免: Always check units before substituting values. Divide volume in cm³ by 1000 to convert to dm³ before calculating concentrations. Write down the rearranged rate equation and verify powers match orders of reactants.
  2. 2high涉及分數: 4Introduction to organic chemistry

    Drawing curly arrows that do not originate clearly from a lone pair or a covalent bond, resulting in zero marks for organic mechanisms.

    如何避免: Draw mechanisms slowly and carefully. Start your arrow directly on the lone pair or the center of the bond, and point it directly to the target atom to show bond formation/cleavage.
  3. 3medium涉及分數: 3Atomic structure

    In Time Of Flight (TOF) calculations, failing to convert the isotopic mass from g/mol to kg/ion by dividing by both Avogadro's constant and 1000.

    如何避免: Use the conversion formula: mass of 1 ion in kg = (molar mass in g / Avogadro's constant) / 1000.
  4. 4high涉及分數: 1Equilibrium constant Kp for homogeneous systems

    Using square brackets instead of round brackets in Kp expressions, which is strictly penalized by AQA examiners.

    如何避免: Write Kp expressions strictly using round brackets and partial pressure notation, e.g., Kp = (p(C))^c / ((p(A))^a * (p(B))^b). Square brackets are exclusively reserved for concentration (Kc).
  5. 5medium涉及分數: 1Optical isomerism

    Describing the overall molecule as planar rather than specifically citing the planar carbonyl group when justifying racemic mixtures.

    如何避免: Always state that the 'planar carbonyl group' or 'planar C=O carbon' is attacked with equal probability from above or below. Avoid stating that the entire molecule is planar unless that is chemically correct and relevant.
  6. 6medium涉及分數: 2Transition metals

    Writing incorrect chemical equations for the reactions of transition metal 3+ ions with sodium carbonate, specifically omitting carbon dioxide gas.

    如何避免: Remember that aqua 3+ ions are highly acidic due to high charge density. When reacted with carbonate ions, they undergo an acid-base reaction forming carbon dioxide gas and a neutral hydroxide precipitate. Always write the gas and water in the equation.
  7. 7medium涉及分數: 1Amount of substance

    Assuming the error in a burette reading is only for a single reading, rather than multiplying by 2 for the total titration error.

    如何避免: Since a titre is calculated by subtracting an initial volume from a final volume, two readings are taken. Multiply the uncertainty of a single reading by 2 to calculate the total titration uncertainty.

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