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.
阅读时间 4 分钟更新于: 2026年6月21日
试卷概览
卷数
3
总分
160
考试时间
3小时
题型
3
试卷
时间
分数
题数
比重
题型
Paper 2 Multiple Choice (Extended)
45分钟
40
—
—
—
Paper 4 Theory (Extended)
1小时 15分钟
80
—
—
—
Paper 6 Alternative to Practical
1小时
40
—
—
—
评级
A*ABCDEFGU
计算器规定
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.
根据历届试题与评分标准整理（2023–2025）。
计算器程序
Table mode for roots & turning points
Scientific calculator (e.g. Casio fx-991 series)
用途: Tabulate \(y\) across a range of \(x\) to locate sign changes (roots) and approximate maxima/minima.
使用时机: Solving or sketching a function when you want to find where its graph crosses or turns.
步骤
Enter the function in TABLE mode, set the start, end and step, then read where the sign of \(y\) changes or where it peaks.
考试提示: 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)
用途: Read the mean \(\bar{x}\) and standard deviation directly, and the gradient/intercept (and \(r\)) of a linear regression for bivariate data.
使用时机: Any data-handling, statistics, or required-practical analysis question.
步骤
Enter the data in STAT mode (1-VAR or A+BX), then recall \(\bar{x}\), \(\sigma\) or the regression coefficients.
考试提示: 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)
用途: Keep full-precision intermediate values to avoid rounding errors.
使用时机: Multi-step calculations where premature rounding loses the final accuracy mark.
步骤
Use Ans, STO/RCL or the M+ memory to reuse the unrounded result of each step; round only the final answer.
考试提示: 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)
用途: Use the built-in EQN/SOLVE mode to verify roots of quadratics or simultaneous equations you have already solved by algebra.
使用时机: As a check only, after solving by hand.
步骤
Enter the coefficients in EQN mode (or use SOLVE) and confirm they match your worked solution.
考试提示: Allowed on papers where a calculator is permitted; use a silent scientific calculator with no stored content and show your method.
常见错误
1high涉及分数: 2Formulae, functional groups and terminology (Organic chemistry)
Omitting the single covalent bond line between oxygen and hydrogen (O-H) in displayed organic formulas.
如何避免: Always show every single bond explicitly as '-O-H' instead of '-OH' when drawing fully displayed structures of alcohols, carboxylic acids, or esters.
2medium涉及分数: 1Extraction of metals (Metals)
Stating that cryolite acts as a catalyst or lowers the melting point of alumina in the extraction of aluminium.
如何避免: Specify that cryolite acts as a solvent to dissolve aluminium oxide, reducing the operational processing temperature.
3high涉及分数: 2Preparation of salts (Acids, bases and salts)
Omitting state symbols in chemical and ionic equations representing precipitation reactions.
如何避免: Always label dissolved ionic reactants as (aq) and the resulting insoluble precipitate as (s) (e.g., BaSO4(s)).
4medium涉及分数: 1Exothermic and endothermic reactions (Chemical energetics)
Omitting the positive (+) or negative (-) signs in enthalpy change calculations and oxidation numbers.
如何避免: 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涉及分数: 2Reversible reactions and equilibrium (Chemical reactions)
Stating that a catalyst shifts the position of dynamic equilibrium or increases the final yield of products.
如何避免: 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涉及分数: 2Experimental design (Experimental techniques and chemical analysis)
In planning questions, forgetting to wash and dry the collected residue before weighing it.
如何避免: 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.