This guide provides expert exam tips, structural details, and a breakdown of common mistakes for Oxford AQA International A-level Chemistry (9620) to help students maximize their marks across all five units.
Short Answer / Structural Drawing, Mathematical Calculation, 選擇題
评级
A*ABCDEU
计算器规定
A scientific or graphical calculator is permitted. Graphical calculators must be in exam mode with all stored programs and data cleared before the exam; 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: Application of knowledge and understanding to unfamiliar situations, qualitative and quantitative contexts (40%)
AO3: AO3: Analysis and evaluation of scientific information, experimental design and practical procedures (25%)
根据历届试题与评分标准整理（2023–2025）。
计算器程序
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.
使用时机: Checking solutions, sketching, or solving where an analytic method is hard.
步骤
Graph the function(s) and use the built-in zero, intersect and maximum/minimum tools.
考试提示: Allowed, but clear stored programs/data (graphical calculators in exam mode) and show the required working — unsupported calculator answers score no method marks.
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.
使用时机: Iterative or implicit equations, or to confirm an algebraic solution.
步骤
Use the equation/zero solver, entering the equation and a sensible starting estimate.
考试提示: Allowed, but clear stored programs/data (graphical calculators in exam mode) and show the required working — unsupported calculator answers score no method marks.
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.
使用时机: Checking calculus answers, or where only a numerical value is needed.
步骤
Use the GDC's numeric integral / derivative function with the limits or the point.
考试提示: Allowed, but clear stored programs/data (graphical calculators in exam mode) and show the required working — unsupported calculator answers score no method marks.
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.
使用时机: Statistics questions and hypothesis tests.
步骤
Enter data in the statistics editor, or use the distribution menu (binomial cdf, normal cdf, …).
考试提示: Allowed, but clear stored programs/data (graphical calculators in exam mode) and show the required working — unsupported calculator answers score no method marks.
常见错误
1high涉及分数: 2Introduction to organic chemistry (Organic chemistry)
Drawing curly arrows that do not originate exactly from a lone pair of electrons or a bond, but rather start from empty space or from an atom label.
如何避免: Ensure the tail of the curly arrow begins precisely on the double bond or the lone pair of the nucleophile/electrophile and points directly to the atom receiving the electrons.
2high涉及分数: 1Amount of substance (Physical chemistry)
Failing to convert the volume of gas from cm3 to m3 (or dm3 to m3) when using the Ideal Gas Equation (PV = nRT).
如何避免: Always multiply the volume in cm3 by 10^-6 to convert to m3 before substituting it into the equation.
Forgetting to convert the isotopic mass of an element from g/mol to kg/mol (by dividing by 1000) when calculating mass of an ion in TOF calculations.
如何避免: Divide the atomic mass by Avogadro's constant and then multiply by 10^-3 to get the mass of a single ion in kilograms.
4high涉及分数: 1Equilibrium constant Kp for homogeneous systems (Physical chemistry)
Using square brackets [ ] instead of round parentheses ( ) when writing expressions for the equilibrium constant Kp.
如何避免: Use partial pressures denoted as p(reactant) within round brackets. Square brackets are strictly reserved for concentrations in Kc.
5medium涉及分数: 1Thermodynamics (Physical chemistry)
Omitting essential state symbols in Born-Haber cycles or when writing equations for first/second ionization energy.
如何避免: Always write down state symbols, paying special attention to gaseous states (g) for atoms and ions when defining ionization energies or lattice enthalpies.
Describing recrystallisation procedures without mentioning that the minimum volume of solvent must be used, or using a Bunsen burner instead of a water bath for flammable mixtures.
如何避免: Always state 'dissolve the solid in the minimum volume of hot solvent' and specify heating with a water bath when solvents are flammable.
7medium涉及分数: 1Alcohols (Organic chemistry)
Improperly drawing vertical bonds to functional groups (e.g. connecting a carbon-carbon vertical chain directly to the H of an OH group rather than the O atom).
如何避免: Ensure vertical bonds explicitly touch the atom that forms the bridge (e.g., C-O-H, not C-H-O) in structural diagrams.