Chemistry Q&A by dot point

Describe the nuclear model of the atom in terms of protons, neutrons and electrons; use nuclear notation and define isotopes; calculate relative atomic mass from isotopic composition determined by mass spectrometry

Describe covalent bonding as the sharing of electron pairs between non-metal atoms, draw Lewis structures for simple molecules and polyatomic ions, predict molecular shape using VSEPR theory, and determine bond polarity and overall molecular polarity from electronegativity differences and geometry

Describe electron configuration in terms of shells, subshells (s, p, d) and orbitals using the (1s 2s 2p 3s 3p 4s 3d 4p) filling order, and explain the periodic trends in atomic radius, first ionisation energy and electronegativity using effective nuclear charge and shielding

Distinguish exothermic and endothermic reactions; represent energy changes using enthalpy values (Delta H) and energy profile diagrams; calculate heat changes (q = mcDeltaT) from calorimetry data and use molar enthalpy of reaction (kJ/mol) in stoichiometric problems

Identify the three classes of intermolecular force (dispersion forces, dipole-dipole forces, hydrogen bonding) and use them to explain the physical properties of covalent molecular substances (melting and boiling points, solubility, viscosity, surface tension)

Describe ionic bonding as the electrostatic attraction between oppositely charged ions in a regular three-dimensional lattice, predict the formula of binary ionic compounds, and relate physical properties (melting point, electrical conductivity, brittleness, solubility) to lattice structure

Describe metallic bonding as the electrostatic attraction between a lattice of metal cations and a sea of delocalised valence electrons, and explain the characteristic properties of metals (electrical and thermal conductivity, malleability, ductility, lustre, variable melting point) in terms of this model

Apply the mole concept to chemical reactions: convert between mass, moles, particles, gas volumes (at STP) and solution concentration; use stoichiometric ratios from a balanced equation to determine limiting reagent, theoretical yield and percentage yield

Calculate the concentration of aqueous solutions in mol/L, g/L, percent by mass or volume, and parts per million (ppm), and apply dilution and stoichiometric relationships to solutions

Apply stoichiometric relationships to reactions involving gases, calculating volumes, masses or amounts of reactants and products using the mole ratio and molar volume or ideal gas equation

Apply the ideal gas equation (PV = nRT) and the concept of molar volume at standard conditions to calculate amounts of gases under varying conditions of temperature and pressure

Explain the behaviour of gases using the kinetic theory of matter, and apply Boyle's law, Charles's law and the combined gas law to predict the effect of changing pressure, volume and temperature

Describe acids and bases qualitatively, distinguish between strong and weak acids using the extent of ionisation, calculate the pH of strong acid and base solutions, and write balanced equations for the reactions of acids with metals, carbonates and hydroxides

Apply solubility rules to predict whether ionic compounds are soluble in water, predict precipitation reactions between aqueous solutions, and write balanced full and net ionic equations including spectator ions

Explain the properties of water as a solvent in terms of its polarity and hydrogen bonding, and describe the dissolution of ionic and polar molecular substances in water

Describe acids and bases using the Bronsted-Lowry model, including the identification of conjugate acid-base pairs, amphiprotic species, and the distinction between strong and weak acids and bases

Describe the composition and action of buffer systems, and explain qualitatively how a buffer resists changes in pH on the addition of small amounts of strong acid or strong base

Explain dynamic equilibrium in terms of rates of forward and reverse reactions, and recognise that equilibrium can only be established in a closed system

Derive and apply the equilibrium law expression (Kc) for homogeneous reactions, including calculating Kc from equilibrium concentrations and predicting the position of equilibrium from the value of Kc

Describe the construction and operation of a galvanic cell, including the role of the salt bridge, the conventions of anode and cathode, and the calculation of standard cell potentials from the standard reduction potential table

Predict, using Le Chatelier's principle, the qualitative effects of changes in concentration, temperature, pressure and volume on the equilibrium position of homogeneous reactions

Determine oxidation numbers and use them to identify oxidation and reduction in chemical reactions, and construct balanced half-equations and overall ionic equations for redox reactions in aqueous solution

Use Kw and the relationship pH = -log10[H3O+] to calculate the pH of strong acid and strong base solutions, and to relate [H3O+] and [OH-] in any aqueous solution

Describe and explain the formation of addition polymers from alkene monomers, and relate the structure of common addition polymers (polyethene, polypropene, polyvinyl chloride, polystyrene, polytetrafluoroethene) to their properties through chain branching and crystallinity

Describe the principles and apply chromatographic techniques (thin-layer chromatography (TLC), gas chromatography (GC) and high-performance liquid chromatography (HPLC)) to separate, identify and quantify the components of a mixture

Describe and explain the formation of condensation polymers (polyesters, polyamides) and relate their structure to the structure and function of biological macromolecules: proteins (from amino acids), carbohydrates (from monosaccharides) and triglycerides (from fatty acids and glycerol)

Describe the principles of green chemistry and apply them to evaluate the sustainability of industrial chemical processes, including atom economy, percentage yield, energy use, choice of solvents and catalysts, and waste management

Describe and explain structural isomerism (chain, position and functional group isomers) and stereoisomerism (cis-trans / geometric isomerism in alkenes) in organic compounds

Apply IUPAC nomenclature to name and write structural formulas for organic compounds including alkanes, alkenes, haloalkanes, alcohols, aldehydes, ketones, carboxylic acids, esters, amines and amides, and classify organic compounds by their functional groups

Describe the principles and apply mass spectrometry and infrared (IR) spectroscopy to determine the molecular mass, molecular formula, structural features and functional groups of organic compounds

Describe and explain trends in the physical properties of organic compounds (melting point, boiling point and solubility in water) in terms of molecular structure, functional groups and intermolecular forces

Describe the principles and apply proton (1H) nuclear magnetic resonance (NMR) spectroscopy to identify the number and types of hydrogen environments, peak ratios (integration) and splitting patterns to determine the structure of organic compounds

Describe and represent reaction pathways for the synthesis of organic compounds, including identifying reagents and conditions required for each step and predicting intermediates

Predict and explain the products of the oxidation of primary, secondary and tertiary alcohols, the oxidation of aldehydes, and the acid-catalysed esterification of carboxylic acids with alcohols (including hydrolysis as the reverse reaction)

Predict and explain the products of substitution reactions of alkanes with halogens and addition reactions of alkenes with halogens, hydrogen halides, hydrogen and water