Changes to H2 Chemistry Syllabus Part 2

H2 Chemistry Syllabus 2017

Part 2 (part 1 here)

H2 chemistry syllabus 2017 updates:

Organic: Constitutional (structural) isomerism. Cis-trans isomerism, used to be geometric isomerism. Enantiomerism used to be optical isomerism.

Nitrogen Compounds (proteins): Not required to learn primary – quaternary structures, as well as list major functions of proteins in the body. Not required to recognize the twenty amino acids and describe α-helix and β-pleated sheet. Not required to describe protein components of haemoglobin. Not required to explain denaturation of proteins.

Electrochemistry: state and apply the relationship ΔGθ = −nFEθ to electrochemical cells. spontaneous redox reaction (ΔG < 0) would mean that E_cell > 0. In other words, the extent of a redox reaction is governed by the sign and magnitude of Eθ_cell, like in the case of ΔGθ.

Since Eθ_cell is dependent on both temperature and concentration (Nernst equation), a non-spontaneous reaction under standard conditions can be made feasible under non-standard conditions (e.g. increasing temperature or concentration).

Similar to the use of ΔGθ to predict the feasibility of a reaction, Eθcell only gives an indication of the thermodynamic feasibility (spontaneity), i.e. based on energy consideration.

The other important aspect, the kinetic feasibility (looking at the activation energy, E_a) must also be considered in order to understand fully whether a reaction is likely to proceed on its own. 

Note that “standard conditions” for both Electrochemistry and Energetics is now 298K, 1 bar and 1 moldm^-3 

Atomic structure: Describe the shapes of d orbitals. This ties in well with the explanation for splitting of degenerate (same energy level) d orbitals.

Transition elements: Describe, using the shape and orientation of the d orbitals, the splitting of degenerate d orbitals into two energy levels in octahedral complexes.

In an octahedral complex, a central metal atom is surrounded by 6 lone pairs of electrons (on the 6 ligands). dx2_y2 orbital and the dz2 orbitals have their lobes pointing at the ligands along the x and y axes, and z axis respectively, hence they experienced greater repulsion from the ligands. The dxy, dyz and dxz orbitals experienced less repulsion since their lobes do not point at the ligands along the axes. Thus the 5 d orbitals are split into 2 energy levels, with higher energy level dx2_y2 and dz2 orbitals and the dxy, dyz and dxz orbitals having the lower energy level

End of H2 Chemistry Syllabus 2017 update~

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Changes in H2 Chemistry syllabus 2017 – part 1

Theories of acids and bases *New!
Arrhenius theory – acid produce H⁺ in water, base produces OH^– in water.
Bronsted Lowry theory – acid produces H⁺, base accepts H⁺. Conjugate pair concept.
Lewis theory – acid as electron pair acceptor, base as electron pair donor.

Gases: V_m = 22.7 dm³ at stp (1 bar, 273 K), 24 dm³ rtp (1 atm, 293 K)

Group 2 & 17 (no longer Roman Numerals) now under Periodicity.

Group 17: Not required to describe the reactions of halide ions with sulfuric acid. Not required to describe the reaction of chlorine with cold and hot aqueous sodium hydroxide.

Group 2: learn thermal stability of carbonates instead of nitrates.

Equilibria: Show understanding that the position of equilibrium is dependent on the standard Gibbs free energy change of reaction, ΔG.
ΔG < 0 means forward reaction is spontaneous (equilibrium constant is >> 1, position of equilibrium lies to the right), > 0 means forward reaction is not spontaneous but backward reaction is (equilibrium constant is < 1, position of equilibrium lies to the left). ΔG = 0 means the system is at equilibrium.

Part 2 here

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Changes in weightage for H2 Chemistry syllabus 2017

‘A’ Level Chemistry Syllabus

Overview of changes in weightage:

Table showing weightage

Table taken from SEAB website

All students required to take practical paper 4, including private candidates.

This means that candidates retaking their A level chemistry paper this year will have to sit for a 20{8445fa0408f68c331c03e03f10d6a7bff33fb7168cc52e9b2191ddf5ec3671a6} weightage practical paper.
Also, their previous SPA scores will not be counted.

So you are a private student retaking A level H2 chemistry this year, do try to enroll yourself in a private school which provides practical lessons.

‘A’ Level Chemistry Syllabus weightage

Paper 1 will be 30 MCQ (with 5-8 Multiple Completion Type) instead of 40 MCQ (10 MCT). Lower weightage.

Paper 2 data-based question will be 20-25 marks out of 75 instead of 15-20 marks out of 72, which gives it a higher weightage.

Planning question shifted from Paper 2 to Paper 4. Weightage is similar ~11/12 marks.

Paper 3 now has two sections, Section A 60 marks of 3-4 compulsory questions. Section B 20 marks, choose one of two questions.
Previously students choose 4 of 5 20 mark questions.
This means that there is lesser chances of avoiding a certain topic since bulk of the questions are compulsory.
Questions will include different topics.

Overall, 5{8445fa0408f68c331c03e03f10d6a7bff33fb7168cc52e9b2191ddf5ec3671a6} of weightage shifted over from MCQ to Paper 2.

There is a shift away from remembering large chunks of information and a shift toward application of knowledge.
Hence there is a real need to guide students to often and consciously apply their knowledge to unfamiliar contexts.

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