An evidence-based study and exam-preparation guide for OCR A Level Chemistry B (Salters) (H433). It compiles critical strategies for tackling transition metal chemistry, Arrhenius calculations, buffer explanations, and organic synthesis pathways directly from past paper trends and examiner insights.
読了時間 4 分更新日: 2026年6月21日
試験の概要
試験数
3
満点
270
制限時間
6時間
出題形式
4
試験
時間
配点
問題数
配点比率
出題形式
H433/01 Fundamentals of Chemistry
2時間 15分
110
35
41%
Multiple Choice, Structured & Short Answer
H433/02 Scientific Literacy in Chemistry
2時間 15分
100
5
37%
Comprehension & Structured
H433/03 Practical Skills in Chemistry
1時間 30分
60
4
22%
Practical Structured Questions
評価段階
A*ABCDEU
電卓の規定
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: Demonstrate knowledge and understanding of scientific ideas, processes, techniques and procedures. (35%)
AO2: AO2: Apply knowledge and understanding of scientific ideas, processes, techniques and procedures. (42%)
AO3: AO3: Analyse, interpret and evaluate scientific information, ideas and evidence, make judgements and reach conclusions. (23%)
過去問と採点基準にもとづいて作成（2022–2024）。
電卓プログラム
Graph: zeros, intersections & turning points
Graphical calculator / GDC (exam mode)
目的: Plot a function to read its roots (zeros), points of intersection, and maxima/minima.
使う場面: Checking solutions, sketching, or solving where an analytic method is hard.
手順
Graph the function(s) and use the built-in zero, intersect and maximum/minimum tools.
試験での注意: 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)
目的: Solve an equation or find a variable numerically when an algebraic route is long or implicit.
使う場面: Iterative or implicit equations, or to confirm an algebraic solution.
手順
Use the equation/zero solver, entering the equation and a sensible starting estimate.
試験での注意: 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)
目的: Evaluate a definite integral \(\int_a^b f(x)\,dx\) or a gradient \(f'(x)\) at a point.
使う場面: Checking calculus answers, or where only a numerical value is needed.
手順
Use the GDC's numeric integral / derivative function with the limits or the point.
試験での注意: 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)
目的: 1-var/2-var statistics, linear regression, and cumulative binomial / normal / Poisson probabilities without tables.
使う場面: Statistics questions and hypothesis tests.
手順
Enter data in the statistics editor, or use the distribution menu (binomial cdf, normal cdf, …).
試験での注意: 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.
よくあるミス
1high影響する配点: 3Kinetics (Developing fuels (DF))
Failing to convert Celsius to Kelvin in Arrhenius and gas calculations.
回避方法: Always add 273 (or 273.15) to any temperature in degrees Celsius before using it in the gas law equation pV = nRT or the Arrhenius equation.
2high影響する配点: 2Energetics (Developing fuels (DF))
Using the mass of the solid instead of the mass of the water/solution in calorimetry calculations.
回避方法: In q = mcΔT, the 'm' always refers to the mass of the solution being heated or cooled (where 1 cm³ = 1 g), never the mass of the solid dissolved or fuel burned.
3high影響する配点: 2Reaction mechanisms (Colour by design (CD))
Drawing reaction mechanism curly arrows starting or ending in arbitrary positions.
回避方法: Ensure curly arrows start precisely from a lone pair of electrons or the center of a covalent bond, and point directly to the specific atom forming the new bond or the bond being broken.
4medium影響する配点: 2Modern analytical techniques (What’s in a medicine? (WM))
Omitting the 'minimum volume' and 'cold solvent' details in recrystallisation descriptions.
回避方法: When describing recrystallisation, explicitly state that you dissolve the crude solid in the *minimum volume* of *hot* solvent, filter hot, cool to crystallize, filter under vacuum, and wash with a small volume of *cold* solvent.
5high影響する配点: 4Equilibria (acid–base) (Polymers and life (PL))
Failing to explain the buffer mechanism by neglecting to state that the concentrations of the weak acid [HA] and its conjugate base [A-] must both remain high and virtually constant.
回避方法: Always state that because [HA] and [A-] are present in large reserves, small additions of H+ or OH- do not significantly alter their ratio, keeping the pH virtually constant.
6medium影響する配点: 1Redox (Elements from the sea (ES))
Incorrectly identifying the oxidizing agent in redox systems by writing down the element rather than the entire molecular/ionic species.
回避方法: Identify the entire active chemical species (e.g., writing Br2 or MnO4-) rather than just the element (such as Br or Mn).
7high影響する配点: 1Formulae, equations and amount of substance (Elements from the sea (ES))
Losing accuracy marks in multi-step titration stoichiometry by using intermediate rounded values.
回避方法: Keep the full precision of intermediate values stored in your calculator's memory (using the ANS button or STO registers) and only round to the final appropriate significant figures at the end.
8medium影響する配点: 2Modern analytical techniques (Polymers and life (PL))
Attributing transition metal complex d-orbital splitting to the 'd-block' rather than 'd-orbitals'.
回避方法: Clearly state that ligand coordination causes the energy of the *d-orbitals* (not d-block) to split into two different levels.