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ICSE chemistry has a reputation for being a memory subject: reactions, colours of precipitates, industrial processes. That is half true. The specimen paper also asks you to calculate moles, read an electrolysis diagram and name organic compounds. This post sets out what CISCE lists for ICSE 2027, how the paper is built, what the practical work involves, and one calculation worked in full.
What does the ICSE 2027 chemistry syllabus include?
The CISCE ICSE 2027 Chemistry syllabus says Class X has "one paper of two hours duration of 80 marks and Internal Assessment of practical work carrying 20 marks." It adds a rule worth copying onto your notebook cover: all reactions "should be studied with reference to the reactants, products, conditions, observations and the (balanced) equations and diagrams."
The nine units are:
Periodic properties and their variations: atomic size, metallic character, ionisation potential, electron affinity, electronegativity. Questions stop at period 4 (calcium).
Chemical bonding: electrovalent, covalent and coordinate bonds with electron dot structures.
Acids, bases and salts: indicators, pH, types of salts and their preparation.
Analytical chemistry: adding sodium hydroxide and ammonium hydroxide to salts of iron, copper, zinc and lead, and amphoteric oxides.
Mole concept and stoichiometry: Gay-Lussac's and Avogadro's laws, molar volume, vapour density, empirical and molecular formulae.
Electrolysis: selective discharge, electroplating and refining of copper.
Metallurgy: ores, extraction of aluminium (Baeyer's and Hall-Heroult processes), alloys.
Study of compounds: hydrogen chloride, ammonia, nitric acid and sulphuric acid.
Organic chemistry: isomerism, homologous series, nomenclature, alkanes to alkynes, ethanol and acetic acid.
Both old (IA to VIIA) and new (1 to 18) group numbers are accepted. CISCE issues a syllabus for each examination year, so check yours.
How is the ICSE 2027 chemistry paper laid out?
The ICSE 2027 Chemistry specimen paper allows two hours after 15 minutes of reading time. Section A (40 marks) is compulsory. Question 1 has 15 one-mark multiple-choice items. Question 2 has five 5-mark parts: an electrolysis diagram, five balanced equations, sentence completion, a matching exercise and IUPAC names. In Section B you answer any four of six questions, each worth 10.
Look at how the draft marking scheme rewards answers. In Question 5, it decides which of two gases has fewer moles in 20 g by dividing 20 by each molar mass. In Question 6, it finds the mass of chromic oxide from a given mass of ammonium dichromate using the equation. Calculations appear across Section B, not in one chapter.
What does the practical assessment test?
The internal assessment asks you to observe the effect of reagents and heat on substances and identify gases (hydrogen, oxygen, carbon dioxide, chlorine, ammonia and others) and ions (copper, iron, lead, zinc, ammonium, carbonate, chloride, nitrate, sulphide, sulphite, sulphate). The minimum practical work includes heating carbonates and nitrates, adding alkalis to unknown salt solutions, and telling an acid from an alkali with two tests each. A formal scheme of analysis is not required. Your subject teacher and an External Examiner each award 10 marks.
Worked example: empirical and molecular formula
A compound contains 40.0% carbon, 6.67% hydrogen and 53.33% oxygen by mass. Its vapour density is 30. Find its molecular formula. (C = 12, H = 1, O = 16.)
Divide each percentage by atomic mass. C: 40.0 ÷ 12 = 3.33. H: 6.67 ÷ 1 = 6.67. O: 53.33 ÷ 16 = 3.33.
Divide by the smallest. 3.33 ÷ 3.33 = 1, 6.67 ÷ 3.33 = 2, 3.33 ÷ 3.33 = 1. Empirical formula: CH2O.
Empirical formula mass: 12 + 2 + 16 = 30.
Molecular mass = 2 × vapour density = 2 × 30 = 60.
n = 60 ÷ 30 = 2, so the molecular formula is C2H4O2. That is acetic acid, which the syllabus covers in unit 9.
Common mistakes: dividing by atomic number instead of atomic mass; rounding 3.33 to 3 too early, which distorts the ratio; and forgetting the factor of 2 between vapour density and molecular mass. More practice is in our post on empirical and molecular formula problems. For unit 4, see our post on ICSE analytical chemistry.
Why test yourself instead of rereading the reactions?
In a well-known study, Roediger and Karpicke (2006) found that students who restudied a passage did better on a test five minutes later, but students who practised recalling it remembered more two days and one week later. A review of ten study techniques by Dunlosky and colleagues (2013) gave practice testing and spaced practice its highest rating. For chemistry, that means writing equations from memory, not reading them again.
A practice routine for the term
Daily, 10 minutes: write five reactions from memory in the five-fact format, then check.
Twice a week: three mole concept or stoichiometry problems.
Weekly: one full Section B question, timed at 15 minutes.
Before each practical: predict the observation, then compare with what you see.
If a gap is in the idea rather than the reaction, such as why ionisation potential rises across a period, the Fermi Concept Library covers every concept in chemistry with its own lesson.
Tonight, write the five facts for the laboratory preparation of ammonia without opening your book.
