Ultimate study guide and exam advice for Cambridge IGCSE Chemistry (0620), compiling actual examiner insights, critical structural pitfalls, and highly high-yield topic blueprints from the 2023-2025 syllabus.
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
160
制限時間
3時間
出題形式
3
試験
時間
配点
問題数
配点比率
出題形式
Paper 2 Multiple Choice (Extended)
45分
40
—
—
—
Paper 4 Theory (Extended)
1時間 15分
80
—
—
—
Paper 6 Alternative to Practical
1時間
40
—
—
—
評価段階
A*ABCDEFGU
電卓の規定
A silent scientific calculator may be used on papers where calculators are permitted (some papers are non-calculator). It must not be graphical or programmable and must hold no stored information.
過去問と採点基準にもとづいて作成（2023–2025）。
電卓プログラム
Table mode for roots & turning points
Scientific calculator (e.g. Casio fx-991 series)
目的: Tabulate \(y\) across a range of \(x\) to locate sign changes (roots) and approximate maxima/minima.
使う場面: Solving or sketching a function when you want to find where its graph crosses or turns.
手順
Enter the function in TABLE mode, set the start, end and step, then read where the sign of \(y\) changes or where it peaks.
試験での注意: Allowed on papers where a calculator is permitted; use a silent scientific calculator with no stored content and show your method.
Statistics mode (mean, SD & regression)
Scientific calculator (e.g. Casio fx-991 series)
目的: Read the mean \(\bar{x}\) and standard deviation directly, and the gradient/intercept (and \(r\)) of a linear regression for bivariate data.
使う場面: Any data-handling, statistics, or required-practical analysis question.
手順
Enter the data in STAT mode (1-VAR or A+BX), then recall \(\bar{x}\), \(\sigma\) or the regression coefficients.
試験での注意: Allowed on papers where a calculator is permitted; use a silent scientific calculator with no stored content and show your method.
Carry exact values with Ans & memory
Scientific calculator (e.g. Casio fx-991 series)
目的: Keep full-precision intermediate values to avoid rounding errors.
使う場面: Multi-step calculations where premature rounding loses the final accuracy mark.
手順
Use Ans, STO/RCL or the M+ memory to reuse the unrounded result of each step; round only the final answer.
試験での注意: Allowed on papers where a calculator is permitted; use a silent scientific calculator with no stored content and show your method.
Equation solver — to CHECK your working
Scientific calculator (e.g. Casio fx-991 series)
目的: Use the built-in EQN/SOLVE mode to verify roots of quadratics or simultaneous equations you have already solved by algebra.
使う場面: As a check only, after solving by hand.
手順
Enter the coefficients in EQN mode (or use SOLVE) and confirm they match your worked solution.
試験での注意: Allowed on papers where a calculator is permitted; use a silent scientific calculator with no stored content and show your method.
よくあるミス
1high影響する配点: 2Formulae, functional groups and terminology (Organic chemistry)
Omitting the single covalent bond line between oxygen and hydrogen (O-H) in displayed organic formulas.
回避方法: Always show every single bond explicitly as '-O-H' instead of '-OH' when drawing fully displayed structures of alcohols, carboxylic acids, or esters.
2medium影響する配点: 1Extraction of metals (Metals)
Stating that cryolite acts as a catalyst or lowers the melting point of alumina in the extraction of aluminium.
回避方法: Specify that cryolite acts as a solvent to dissolve aluminium oxide, reducing the operational processing temperature.
3high影響する配点: 2Preparation of salts (Acids, bases and salts)
Omitting state symbols in chemical and ionic equations representing precipitation reactions.
回避方法: Always label dissolved ionic reactants as (aq) and the resulting insoluble precipitate as (s) (e.g., BaSO4(s)).
4medium影響する配点: 1Exothermic and endothermic reactions (Chemical energetics)
Omitting the positive (+) or negative (-) signs in enthalpy change calculations and oxidation numbers.
回避方法: Always prefix enthalpy values with '-' for exothermic or '+' for endothermic reactions, and include correct signs for oxidation states (e.g., '+6' instead of '6').
5high影響する配点: 2Reversible reactions and equilibrium (Chemical reactions)
Stating that a catalyst shifts the position of dynamic equilibrium or increases the final yield of products.
回避方法: Explain that a catalyst only increases the rate of both forward and reverse reactions equally, speeding up how fast equilibrium is reached without changing the yield.
6high影響する配点: 2Experimental design (Experimental techniques and chemical analysis)
In planning questions, forgetting to wash and dry the collected residue before weighing it.
回避方法: Always include a step to wash the filtered residue with distilled water and dry it in a warm oven or with filter paper to achieve a constant mass.