Wales · WJECQ&A
ChemistryQ&A by dot point
A short Q&A bank for every Wales Chemistry syllabus dot point. Each question and answer is drawn directly from our worked dot-point page, so you can scan key concepts before opening the long-form answer.
Unit 2.2 Acids, bases and salts
- Describe the properties of acids and bases, the ions they produce in solution, and use the pH scale and indicators to classify solutions.0Q&A pairs
- Describe neutralisation in terms of hydrogen and hydroxide ions and write equations for reactions of acids with metals, bases and carbonates.0Q&A pairs
- Describe how to prepare a pure, dry soluble salt from an acid and an insoluble base or carbonate, and how to make an insoluble salt by precipitation.0Q&A pairs
- Describe tests for halide ions using silver nitrate, sulfate ions using barium chloride, and carbonate ions using dilute acid.0Q&A pairs
- Describe tests for hydrogen, oxygen, carbon dioxide and chlorine, flame tests for metal ions, and tests for metal cations using sodium hydroxide solution.0Q&A pairs
Unit 2.1 Bonding, structure and properties
- Describe covalent bonding as shared pairs of electrons, draw dot-and-cross diagrams for simple molecules, and relate simple molecular structure to low melting points and poor conduction.0Q&A pairs
- Describe giant covalent structures including diamond and graphite, and relate their bonding and structure to their very different properties.0Q&A pairs
- Describe ionic bonding as electron transfer, draw dot-and-cross diagrams for simple ionic compounds, and relate the giant ionic lattice to the properties of ionic compounds.0Q&A pairs
- Describe metallic bonding as positive ions in a sea of delocalised electrons, relate it to metal properties, and explain why alloys are harder than pure metals.0Q&A pairs
- Use the properties of a substance (melting point, conductivity, state) to deduce its type of bonding and structure.0Q&A pairs
Unit 2: Crude Oil and Organic Chemistry
- Alcohols as a homologous series, the functional group, and the production of ethanol by fermentation and by hydration of ethene.2Q&A pairs
- Alkanes and alkenes as homologous series, the test for unsaturation, combustion of hydrocarbons, and cracking to make smaller alkanes and alkenes.3Q&A pairs
- Crude oil as a mixture of hydrocarbons, separation by fractional distillation, and the properties and uses of the fractions.2Q&A pairs
- Addition polymerisation of alkenes, drawing the repeat unit, the uses of common polymers, and the problems of polymer waste and disposal.2Q&A pairs
Unit 2: Metals and their Extraction
- The properties and uses of alloys, why alloys are harder than pure metals, and the economic and environmental reasons for recycling metals.2Q&A pairs
- Electrolysis of molten ionic compounds, the reactions at the electrodes, and the extraction of aluminium from molten aluminium oxide.3Q&A pairs
- Metal ores, extraction by reduction with carbon for metals below carbon in the reactivity series, and the reactions of the blast furnace.2Q&A pairs
- The reactivity series, reactions of metals with water and dilute acid, and displacement reactions of metals from solutions of their salts.3Q&A pairs
Unit 2.4 Chemical reactions and energy
- Explain bond breaking and bond making in terms of energy and calculate the energy change of a reaction from bond energies.0Q&A pairs
- Describe exothermic and endothermic reactions, draw and interpret reaction profiles, and identify activation energy and overall energy change.0Q&A pairs
- Describe and explain the effect of temperature, concentration or pressure, surface area and catalysts on rate using collision theory.0Q&A pairs
- Define the rate of reaction, describe how it is measured, and use collision theory to explain how reactions occur.0Q&A pairs
- Describe reversible reactions and dynamic equilibrium, and predict the effect of changing temperature, concentration and pressure using Le Chatelier's principle.0Q&A pairs
- Describe the Haber process and the Contact process, including their conditions, and explain why the conditions are a compromise between yield, rate and cost.0Q&A pairs
Unit 1.2 Atomic structure and the Periodic Table
- Describe sub-atomic particles and their relative masses and charges, work out particle numbers from atomic and mass number, define isotopes, and calculate relative atomic mass.0Q&A pairs
- Represent reactions by word and balanced symbol equations, apply the law of conservation of mass, and classify reactions as exothermic or endothermic.0Q&A pairs
- Carry out paper chromatography, interpret chromatograms, and calculate and use Rf values to identify substances in a mixture.0Q&A pairs
- Describe the arrangement of electrons into shells for the first twenty elements and relate electronic structure to group and period in the Periodic Table.0Q&A pairs
- Distinguish between elements, compounds and mixtures, interpret chemical formulae, and tell physical changes apart from chemical reactions.0Q&A pairs
- Describe the arrangement of the Periodic Table, distinguish metals and non-metals, and explain trends in Group 1, Group 7 and Group 0.0Q&A pairs
Unit 1: The Earth, Atmosphere and Resources
- Greenhouse gases and climate change, the combustion products that pollute the air, and the problems each pollutant causes.2Q&A pairs
- Limestone and its uses, the thermal decomposition of calcium carbonate, the reactions of the limestone cycle, and building materials made from limestone.2Q&A pairs
- The composition of today's atmosphere, the early atmosphere, and how the proportions of carbon dioxide and oxygen changed over geological time.2Q&A pairs
- The water cycle, treatment of water for drinking, the test for water, and solubility including the difference between dilute and concentrated solutions.2Q&A pairs