ChemistryQ&A by dot point

Acids, bases and the pH scale: hydrogen and hydroxide ions, indicators, the pH scale and hydrogen ion concentration, strong and weak acids, dilute and concentrated, and neutralisation.

Electrolysis: electrolysis of molten ionic compounds and aqueous solutions, predicting the products at the electrodes, writing half-equations, and the electrolysis of copper sulfate core practical.

Preparing salts: making a soluble salt from an insoluble base, the titration method for soluble salts of soluble bases, preparing insoluble salts by precipitation, and the two core practicals.

Reactions of acids: the general reactions of acids with metals, metal oxides, metal hydroxides and metal carbonates, the salts produced, and the tests for hydrogen and carbon dioxide.

Reversible reactions and equilibria: reversible reactions and the use of the reversible arrow, the energy change in each direction, dynamic equilibrium in a closed system, and the idea that the conditions affect the position of equilibrium.

Reactions of metals: reactions with oxygen, water and dilute acids, using these to place metals in a reactivity series, displacement reactions, and recycling and life cycle considerations.

Extracting metals: the reactivity series, oxidation and reduction in terms of oxygen and electrons, extraction by reduction with carbon, extraction by electrolysis, and alternative biological methods.

Hydrocarbons and fuels: crude oil and the alkanes, fractional distillation into useful fractions, the trends in the properties of the fractions, complete combustion, and cracking.

Pollution from fuels: incomplete combustion and carbon monoxide and soot, sulfur dioxide and oxides of nitrogen, acid rain, and the advantages and disadvantages of hydrogen as a fuel.

The Earth and atmosphere: the evolution of the atmosphere from volcanic gases to the present composition, the role of photosynthesis, the greenhouse effect, and human activities affecting greenhouse gas levels.

Group 0 the noble gases: their lack of reactivity explained by full outer shells, the trends in boiling point and density down the group, and their uses.

Group 1 the alkali metals: their physical properties, their reactions with water and oxygen, the trend in reactivity down the group, and the explanation in terms of electronic structure.

Group 7 the halogens: their physical properties and trends, their reactions to form ions and compounds, the decreasing reactivity down the group, and halogen displacement reactions.

Atomic structure: protons, neutrons and electrons, atomic number and mass number, isotopes and relative atomic mass, and the development of the model of the atom.

Calculations in chemistry: relative formula mass, percentage by mass, empirical formulae from masses, reacting masses from balanced equations, concentration in grams per cubic decimetre, and the mole.

Chemical formulae and equations: writing formulae from ions, balancing symbol equations, state symbols, ionic equations and half-equations, and the law of conservation of mass.

Covalent and metallic bonding: shared electron pairs, simple molecular and giant covalent structures (diamond, graphite, fullerenes, graphene), polymers, metallic bonding, and how each structure explains properties.

Ionic bonding: the formation of ions by electron transfer, dot-and-cross diagrams, the giant ionic lattice, and how the structure explains the properties of ionic compounds.

The periodic table: how the elements are arranged by atomic number into groups and periods, the development of the table by Mendeleev, metals and non-metals, and electronic configurations of the first 20 elements.

Bond energy calculations: breaking bonds is endothermic and making bonds is exothermic, and calculating the overall energy change of a reaction from bond energies.

Exothermic and endothermic reactions: the energy transfer to or from the surroundings, examples and temperature changes, reaction profiles and activation energy, and the core practical on temperature change.

Measuring rates and catalysts: the core practicals measuring rate by gas volume and by a colour change, calculating rate from a graph, and how catalysts work by lowering the activation energy.

Rates of reaction and collision theory: the meaning of rate, how concentration, pressure, surface area and temperature affect rate, and the explanation in terms of collision frequency and activation energy.

Quantitative analysis: the mole and concentration in mol/dm3, converting between g/dm3 and mol/dm3, the acid-alkali titration core practical, and calculating an unknown concentration from titration results.

Transition metals, alloys and corrosion: the properties of transition metals compared with Group 1, the structure and uses of alloys, the conditions needed for rusting, and methods of preventing corrosion.

Yield and gas calculations: percentage yield and why yields are below 100 percent, atom economy and sustainability, and calculating gas volumes using the molar volume of a gas.

Alcohols and carboxylic acids: the alcohol and carboxylic acid homologous series, their functional groups, the reactions of alcohols including combustion and oxidation, and the reactions of carboxylic acids.

Polymers and materials: addition polymerisation of alkenes, condensation polymerisation, the properties and uses of polymers, comparing materials, and life cycle assessment.

Qualitative analysis tests for ions: flame tests for metal cations, tests for cations using sodium hydroxide, tests for anions (carbonate, sulfate, halide), and identifying ions in an unknown salt.

Paper chromatography and Rf values: how chromatography separates a mixture, the core practical investigating inks, calculating Rf values, and identifying substances from a chromatogram.

Mixtures and separation: pure substances and mixtures, the separation techniques (filtration, crystallisation, simple and fractional distillation), and producing potable water.

States of matter: the particle model of solids, liquids and gases, the changes of state and their names, state symbols, and the limitations of the simple particle model.