ChemistryQ&A by dot point

Reaction rate and how it is followed, collision theory, the effect of concentration, particle size, temperature and catalysts on rate, the activation energy, the activated complex and the potential energy diagram.

Oxidation and reduction defined in terms of electron loss and gain, the meaning of oxidising and reducing agents, writing ion-electron half-equations, combining them into redox equations, and the electrochemical series.

The trends in covalent radius, first ionisation energy and electronegativity across periods and down groups, explained in terms of nuclear charge, number of occupied shells and the screening effect of inner electrons.

The arrangement of elements in the periodic table by atomic number into groups and periods, the link between electron arrangement and chemical behaviour, and the meaning of covalent radius, ionisation energy and electronegativity.

The types of bonding and structure (covalent molecular, covalent network, ionic, metallic), the intermolecular forces including London dispersion forces, permanent dipole-permanent dipole interactions and hydrogen bonding, and how these explain physical properties.

The principles of chromatography for separating mixtures, the use of volumetric (titration) analysis to find an unknown concentration, the idea of standard solutions, and how to interpret analytical data to identify and quantify substances.

Enthalpy changes of combustion, formation and neutralisation, the calculation of energy released using the formula relating energy, mass, specific heat capacity and temperature change, and the use of Hess's law to find an unknown enthalpy change.

Dynamic equilibrium in reversible reactions, the effect of concentration, pressure, temperature and catalysts on the position of equilibrium, Le Chatelier's principle, and how industry uses these to maximise yield.

Calculations of percentage yield and atom economy, the use of an excess reagent, identifying the limiting reactant, and the factors that make an industrial process efficient and sustainable.

The use of oxidising agents as antiseptics, bleaches and in rocket fuels, the action of oxidising agents in killing bacteria and breaking down coloured compounds, redox titrations, and combining half-equations to give a balanced redox equation.

Flavour molecules, the effect of cooking on flavour, the difference between aldehydes and ketones, oxidation of aldehydes, and the volatility and solubility of flavour and aroma compounds.

The formation of esters by condensation of an alcohol and a carboxylic acid, the ester link, hydrolysis of esters, and the structure of fats and oils as esters of glycerol and fatty acids, including saturated and unsaturated chains.

Essential oils and terpenes as components of fragrances, the structure of terpenes built from isoprene units, the oxidation of terpenes, and how UV light damages skin and how sunblocks and free-radical scavengers protect it.

Oxidation as the loss of electrons, the oxidation of alcohols and aldehydes, the rancidity of edible oils caused by the oxidation of carbon-to-carbon double bonds, and the action of antioxidants in preventing oxidation.

Amino acids as the building blocks of proteins, the formation of the peptide (amide) link by condensation, the hydrolysis of proteins to amino acids, essential amino acids, and how heat denatures the structure of enzymes.

The production of soap by alkaline hydrolysis of fats and oils, the structure of soap with hydrophilic and hydrophobic ends, how soap removes oily dirt, hard water, detergents, and the action of emulsifiers in emulsions.

Practical skills for Researching Chemistry, including planning and hazard assessment, the use and selection of common chemical apparatus, gravimetric analysis to find a quantity by mass, volumetric analysis, and judging the accuracy, precision and reliability of results, as assessed in the question paper and the assignment.