Should I Choose H1 or H2 Chemistry?
Students interested in taking chemistry at Singapore GCE A Levels are able to choose between H1 Chemistry (Syllabus 8873) and H2 Chemistry (Syllabus 9729).
This article is an in-depth comparison between the 2 syllabuses, scrupulously compiled by Chemistry Guru, one of the top JC chemistry tuition centres in Singapore since 2010.
This will help new JC students decide which course to take.
It will also be useful to existing H2 Chemistry students who are considering dropping to H1 Chemistry and help them make a well-informed decision.
| Contents (click to jump to section) |
1. Career Prospects of H1 and H2 Chemistry
Candidates are assumed to have knowledge and understanding of O-Level Chemistry (Pure or Combined), and not allowed to take both H1 and H2 Chemistry concurrently.
The aims of both syllabuses are similar but H2 Chemistry has the additional objective to build the knowledge, skills and attitudes needed for further studies in related fields.
This means H2 Chemistry will be a subject requirement in certain university courses such as dentistry, medicine, nursing, pharmacy and pharmaceutical science (source:NUS) while H1 Chemistry is not.
For instance, students will need a "good H2 pass in Chemistry and H2 pass in either Biology or Physics" to apply for NUS Medicine.
Therefore students are advised to consider the university courses they are interested in pursuing before choosing H1 or H2 Chemistry.
2. Curriculum Framework of H1 and H2 Chemistry
The key features of both curriculum are similar which consist of Core Ideas and Extension Topics as illustrated in Fig 1 and 2.
Fig. 1: H1 Chemistry Content Map
Fig. 2: H2 Chemistry Content Map
The Core Idea topics are similar for both syllabuses with fewer learning objectives for H1 Chemistry as compared to H2 Chemistry.
Extension topics are significantly different for both syllabuses:
H1 Chemistry - Nanomaterials and Polymers
H2 Chemistry - Chemistry of Aqueous Solutions, Organic Chemistry, Electrochemistry and Chemistry of Transition Elements.
3. Assessment for H1 and H2 Chemistry
Students taking H1 Chemistry are required to enter for two papers: Multiple Choice and Structured Questions.
Paper | Type of Paper | Duration | Weighting (%) | Marks |
1 | Multiple Choice | 1 h | 33 | 30 |
2 | Structured Questions | 2 h | 67 | 80 |
Students taking H2 Chemistry need to attempt four papers: Multiple Choice, Structured Questions, Free Response and Practical.
Paper | Type of Paper | Duration | Weighting (%) | Marks |
1 | Multiple Choice | 1 h | 15 | 30 |
2 | Structured Questions | 2 h | 30 | 75 |
3 | Free Response Questions | 2 h | 35 | 80 |
4 | Practical | 2 h 30 min | 20 | 55 |
The most notable difference will be the practical exam for H2 Chemistry students.
Students struggling with chemistry practical may consider taking H1 Chemistry instead.
4. Subject Content for H1 and H2 Chemistry
Here is the detailed comparison for all the topics in H1 and H2 Chemistry.
CORE IDEA 1 – MATTER
1. Atomic Structure
| H1 Chemistry | H2 Chemistry |
- The nucleus of the atom: neutrons and protons, isotopes, proton and nucleon numbers - Electrons: electronic energy levels, ionisation energies, atomic orbitals, extranuclear structure | - The nucleus of the atom: neutrons and protons, isotopes, proton and nucleon numbers - Electrons: electronic energy levels, ionisation energies, atomic orbitals, extranuclear structure |
This topic Atomic Structure is very similar for both syllabuses, with the following additional learning objectives for H2 Chemistry:
- describe the shapes of d orbitals
CORE IDEA 2 – STRUCTURE AND PROPERTIES
2. Chemical Bonding
| H1 Chemistry | H2 Chemistry |
- Ionic bonding, metallic bonding, covalent bonding and co-ordinate (dative covalent) bonding - Shapes of simple molecules and bond angles - Bond polarities and polarity of molecules - Intermolecular forces, including hydrogen bonding - Bond energies and bond lengths - Lattice structure of solids - Bonding and physical properties | - Ionic bonding, metallic bonding, covalent bonding and co-ordinate (dative covalent) bonding - Shapes of simple molecules and bond angles - Bond polarities and polarity of molecules - Intermolecular forces, including hydrogen bonding - Bond energies and bond lengths - Lattice structure of solids - Bonding and physical properties |
This topic Chemical Bonding is very similar for both syllabuses, with the following additional learning objectives for H1 Chemistry:
- outline the importance of intermolecular forces to the liquefaction of gases when subjected to high pressure and/or low temperature
3. The Gaseous State
| H1 Chemistry | H2 Chemistry |
Not Applicable | - Ideal gas behaviour and deviations from it - pV = nRT and its use in determining a value for Mr - Dalton’s Law and its use in determining the partial pressures of gases in a mixture |
This topic The Gaseous State is only for H2 Chemistry and not required for H1 Chemistry.
4. Theories of Acids and Bases
| H1 Chemistry | H2 Chemistry |
- Arrhenius and Brønsted-Lowry theories of acids and bases - Acid dissociation constants, Ka - Base dissociation constants, Kb - The ionic product of water, Kw - pH: choice of indicators - Buffer solutions | - Arrhenius, Brønsted-Lowry and Lewis theories of acids and bases |
This topic Theories of Acids and Bases might seem more in-depth for H1 Chemistry but the additional content such as acid and base dissociation constants, ionic product of water and buffer solutions are covered to greater extent in H2 Chemistry under Extension Topics: Chemistry of Aqueous Solutions.
5. The Periodic Table
| H1 Chemistry | H2 Chemistry |
- Periodicity of atomic and physical properties of the elements: variation with proton number across the third period (sodium to chlorine) and down Group 17 of: (i) electronic configuration (ii) atomic radius and ionic radius (iii) ionisation energy (iv) electronegativity (v) melting point (vi) electrical conductivity - Periodicity of chemical properties of the elements in the third period: (i) variation in oxidation number and bonding of the oxides (sodium to sulfur only) and of the chlorides (sodium to phosphorus only) (ii) reactions of these oxides and chlorides with water (iii) acid/base behaviour of these oxides and the corresponding hydroxides - Periodicity of chemical properties of the elements down the group (Group 1 and Group 17): (i) as reducing agents (Group 1) and oxidising agents (Group 17) (ii) thermal stability of Group 17 hydrides | - Periodicity of atomic and physical properties of the elements: variation with proton number across the third period (sodium to chlorine) and down the group (Group 2 and Group 17) of: (i) electronic configuration (ii) atomic radius and ionic radius (iii) ionisation energy (iv) electronegativity (v) melting point (vi) electrical conductivity - Periodicity of chemical properties of the elements in the third period: (i) variation in oxidation number and bonding of the oxides (sodium to sulfur only) and of the chlorides (sodium to phosphorus only) (ii) reactions of these oxides and chlorides with water (iii) acid/base behaviour of these oxides and the corresponding hydroxides - Periodicity of chemical properties of the elements down the group (Group 2 and Group 17): (i) as reducing agents (Group 2) and oxidising agents (Group 17) (ii) thermal stability of Group 2 carbonates and Group 17 hydrides |
This topic The Periodic Table is very similar for both syllabuses for periodicity across the third Period (sodium to chlorine) and down Group 17.
The main difference is H1 Chemistry includes periodicity of chemical properties down Group 1 metals, while H2 Chemistry includes periodicity of chemistry properties down Group 2 metals and thermal stability of Group 2 carbonates.
CORE IDEA 3 – TRANSFORMATION
6. The Mole Concept and Stoichiometry
| H1 Chemistry | H2 Chemistry |
- Relative masses of atoms and molecules - The mole, the Avogadro constant - The calculation of empirical and molecular formulae - Reacting masses and volumes (of solutions and gases) - Redox processes: electron transfer and changes in oxidation number (oxidation state) | - Relative masses of atoms and molecules - The mole, the Avogadro constant - The calculation of empirical and molecular formulae - Reacting masses and volumes (of solutions and gases) |
This topic The Mole Concept and Stoichiometry might seem more in-depth for H1 Chemistry but the additional content redox processes and balancing redox equations using half-equations are covered in H2 Chemistry under Extension Topics: Electrochemistry.
7. Chemical Energetics: Thermochemistry and Thermodynamics
| H1 Chemistry | H2 Chemistry |
- Enthalpy changes: ΔH, of formation; combustion; neutralisation; bond energy; lattice energy - Hess’ Law [construction of energy cycles is not required] | - Enthalpy changes: ΔH, of formation; combustion; hydration; solution; neutralisation; atomisation; bond energy; lattice energy; electron affinity - Hess’ Law, including Born-Haber cycles - Entropy and Free Energy |
This topic Chemical Energetics has the following additional learning objectives for H2 Chemistry:
- explain and use the terms: enthalpy change of hydration; solution; atomisation; electron affinity
- apply Hess' Law to construct energy cycles e.g. Born-Haber cycle and formation of a simple ionic solid and of its aqueous solution, and carry out calculations involving such cycles and relevant energy terms
- Thermodynamics: Entropy and Gibbs free energy
8. Reaction Kinetics
| H1 Chemistry | H2 Chemistry |
- Simple rate equations; orders of reaction; rate constants - Concept of activation energy - Effect of concentration, temperature, and catalysts on reaction rate - Heterogeneous catalysts - Enzymes as biological catalysts | - Simple rate equations; orders of reaction; rate constants - Concept of activation energy - Effect of concentration, temperature, and catalysts on reaction rate - Homogeneous and heterogeneous catalysis - Enzymes as biological catalysts |
This topic Reaction Kinetics has the following additional learning objectives for H2 Chemistry:
- explain and use the terms: rate-determining step
- verifying that a suggested reaction mechanism is consistent with the observed kinetics and deducing the order from a given reaction mechanism
- use the half-life of a first-order reaction in calculations
- calculate rate constant using initial rates method
- devise a suitable experimental technique for studying the rate of a reaction
- outline the mode of action of heterogeneous catalysis in the Haber process
- outline the mode of action of homogeneous catalysis in the oxidation of atmospheric sulfur dioxide by oxides of nitrogen and the I–/S2O82– reaction by Fe2+
- explain the relationship between substrate concentration and the rate of an enzyme-catalysed reaction in biochemical systems
9. Chemical Equilibria
| H1 Chemistry | H2 Chemistry |
- Chemical equilibria: reversible reactions; dynamic equilibrium (i) factors affecting chemical equilibria (ii) equilibrium constants (iii) the Haber process | - Chemical equilibria: reversible reactions; dynamic equilibrium (i) factors affecting chemical equilibria (ii) equilibrium constants (iii) the Haber process |
This topic Chemical Equilibria has the following additional learning objectives for H2 Chemistry:
- deduce expressions for equilibrium constants in terms of partial pressures, Kp
calculate the values of equilibrium constants in terms of partial pressures from appropriate data
show understanding that position of equilibrium is dependent on the standard Gibbs free energy change of reaction, ΔGθ
EXTENSION TOPICS
The Extension Topics for H1 Chemistry and H2 Chemistry are very different.
| H1 Chemistry | H2 Chemistry |
- Nanomaterials - Polymers | - Chemistry of Aqueous Solutions (Acid-base Equilibria, Solubility Equilibria) - Organic Chemistry - Electrochemistry - Introduction to Chemistry of Transition Elements |
The topic Polymers in H1 Chemistry is a simplified version of Organic Chemistry in H2 Chemistry with the following notable differences for Polymers:
- hybridisation is not required
- interpreting chirality, optical isomerism and stereochemical formula that shows spatial arrangement of bonds, atoms and groups in molecule in 3-D are not required
interpreting the following functional groups are not required: halogenoarenes, phenols, acyl chlorides, amino acids and nitriles
drawing mechanism and interpreting the following terms associated with organic reactions and reactivities are not required: degree of substitution; homolytic and heterolytic fission; carbocation; free radical, initiation, propagation, termination; electrophile; nucleophile; delocalisation; electronic effect; steric effect
- for memorising organic reactions, only the following are required:
- alkanes as being generally unreactive except in terms of combustion and substitution by chlorine
- alkenes in terms of combustion and addition reactions with bromine (in CCl4) and hydrogen
- halogenoalkanes in terms of substitution reaction to alcohols and elimination reactions to alkenes
- aldehydes and ketones in terms of their reduction to primary and secondary alcohols respectively; and oxidation of aldehydes to carboxylic acids
- alcohols in terms of combustion, oxidation to carboxylic acids and elimination to alkenes
carboxylic acids in terms of condensation with alcohols to form esters, and with amines to form amides
esters and amides in terms of hydrolysis with acids and bases
- the learning objectives on polymers are specific to H1 Chemistry and not required for H2 Chemistry
5. Conclusion - H1 or H2 Chemistry?
We hope students will have a better idea whether to choose H1 or H2 Chemistry after reading this detailed comparison of both syllabuses compiled by Chemistry Guru, Singapore's leading A Level Chemistry tuition centre.
Here's a summary of what to consider:
| Question | Choose H1 Chemistry if | Choose H2 Chemistry if |
Career Prospects: What are you intending to study in university? | you just need chemistry as a contrasting subject | you need H2 chemistry as a prerequisite for university courses such as medicine, nursing or pharmacy |
| Assessment: Are you proficient with chemistry practical? | you struggle with chemistry practical | you are proficient with chemistry practical |
| Subject Content: Are you proficient with advanced chemistry concepts? | you struggle with memorising organic chemistry reactions; drawing mechanisms, and other advanced extension topics such as acid-base equilibria; solubility equilibria; electrochemistry and transition elements | you are proficient with memorising organic chemistry reactions; drawing mechanisms, and other advanced extension topics such as acid-base equilibria; solubility equilibria; electrochemistry and transition elements |
For current H2 Chemistry students who are struggling with topics like organic chemistry and need guidance from an experienced Chemistry tutor, do consider signing up for classes at Chemistry Guru.
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