Mathematical, structural convention and data skills
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Mathematical requirements
M.1—Arithmetic, rounding, percentages, means and significant figures
Perform addition, subtraction, multiplication and division; understand integers; estimate numerical expressions; round numbers correctly; give answers to appropriate significant figures; calculate percentages, convert fractions and percentages, and calculate arithmetic means.
M.2—Unit conversions, standard form, logs and algebra
Convert cm3, dm3 and m3; nm and m; Pa and kPa; seconds and minutes; mg, g, kg and tonne; Celsius and Kelvin; J and kJ. Use standard form, logarithms for pH, powers, roots and reciprocals; rearrange formulae; substitute quantities with consistent units; solve simple algebraic equations.
M.3—Graphs, proportionality, gradients and intercepts
Test direct proportionality by graph or constant ratio; choose variables and scales; plot linear graphs of y = mx + c; determine and interpret gradient and intercept; choose best-fit lines or curves; use plotted points marked as crosses or circled dots.
M.4—Curves, models, logarithms and core chemical formulae
Interpret tangent gradients as rates of change and areas under curves where physically meaningful; estimate orders of magnitude; set up simple algebraic models such as rate equations and identify limitations; use log x and ln x; calculate density, concentration and number of moles.
M.5—Key quantities, symbols and units
Use key quantities, symbols and units correctly, including mass, length, time, current, temperature, amount of substance, Avogadro constant, potential difference, charge, Faraday constant, half-life, Kw, R, Ar, Mr, E standard, enthalpy change and volume.
Organic structure and mechanism conventions
Reference—Structural, displayed and skeletal formula conventions
Represent organic compounds using accepted structural, displayed, skeletal and partial-skeletal formula conventions; give enough detail for an unambiguous structure; use the preferred aromatic ring convention.
Reference—Optical isomer drawing convention
Draw pairs of optical isomers using the three-dimensional wedge/dash style convention shown in the syllabus, making mirror-image relationships clear.
Reference—Organic reaction mechanism conventions
Draw organic reaction mechanisms using charges, dipoles, lone pairs of electrons and curly arrows to show electron movement and mechanism steps clearly.
Data section reference
Data reference—Important constants and standards
Use supplied constants and standards including R, F, Avogadro constant, electronic charge, molar gas volume at s.t.p. and room conditions, Kw and specific heat capacity of water.
Data reference—Ionisation energies, electronegativity and Periodic Table
Use ionisation energy tables, Pauling electronegativity values and the Periodic Table to support explanations of trends, bonding, periodicity and chemical behaviour.
Data reference—Bond energies
Use exact and average bond energy tables to calculate or interpret enthalpy changes and compare bond strengths, remembering that average bond energies are approximations.
Data reference—Standard electrode potentials
Use standard electrode potential tables to calculate cell potentials, predict feasibility, compare oxidising/reducing strength and interpret redox behaviour.
Data reference—Proton and carbon-13 NMR chemical shifts
Use proton NMR and carbon-13 NMR chemical shift ranges to identify chemical environments and support structural deduction.
Data reference—Infrared absorption frequencies
Use characteristic infrared absorption frequency ranges to identify selected bonds and functional groups, especially in combination with other analytical evidence.