Companion PDF worksheet for Edexcel IGCSE Chemistry Lecture 13 - Covalent Bonding. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 1.44 - Know that a covalent bond is formed between atoms by the sharing of a pair of electrons. Specification Point 1.45 - Understand covalent bonds in terms of electrostatic attractions. Specification Point 1.46 - Understand how to use dot-and-cross diagrams to represent covalent bonds in a variety of molecules. Specification Point 1.47 - Explain why substances with a simple molecular structures are gases or liquids, or solids with low melting and boiling points. Specification Point 1.48 - Explain why the melting and boiling points of substances with simple molecular structures increase, in general, with increasing relative molecular mass. Specification Point 1.49 - Explain why substances with giant covalent structures are solids with high melting and boiling points. Specification Point 1.50 - Explain how the structures of diamond, graphite and fullerene influence their physical properties, including electrical conductivity and hardness. Specification Point 1.51 - Know that covalent compounds do not usually conduct electricity. Complete set of Chapter 3 Worksheets are available.

Companion PDF worksheet for Edexcel IGCSE Chemistry Lecture 6 - Paper Chromatography. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 1.11 - Understand how a chromatogram provides information about the composition of a mixture. Specification Point 1.12 - Understand how to use the calculation of Rf values to identify the components of a mixture. Specification Point 1.13 - Practical: understand how a chromatogram provides information about the composition of a mixture. Complete set of Chapter 1 Worksheets are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.3.1 - Issues and debates in psychology. Ethical implications of research studies and theory, including reference to social sensitivity. Complete set of Chapter 8 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.2.1 - Approaches in psychology. The psychodynamic approach: the role of the unconscious, the structure of personality, that is Id, Ego and Superego, defence mechanisms including repression, denial and displacement, psychosexual stages. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.3.6 - Eating behaviour. Explanations for food preferences: the evolutionary explanation, including reference to neophobia and taste aversion; the role of learning in food preference, including social and cultural influences. Complete set of Chapter 13 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.3.1 - Issues and debates in psychology. Holism and reductionism: levels of explanation in psychology. Biological reductionism and environmental (stimulus-response) reductionism. Complete set of Chapter 8 Lectures are available.

Companion PDF worksheet for Edexcel IGCSE Chemistry Lecture 31 - Organic Compounds. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 4.1 - Know that a hydrocarbon is a compound of hydrogen and carbon only. Specification Point 4.2 - Understand how to represent organic molecules using empirical formulae, molecular formulae, general formulae, structural formulae and displayed formulae. Specification Point 4.3 - Know what is meant by the terms homologous series, functional group and isomerism. Specification Point 4.4 - Understand how to name compounds relevant to this specification using the rules of IUPAC nomenclature. Specification Point 4.5 - Understand how to write the possible structural and displayed formulae of an organic molecule given its molecular formula. Specification Point 4.6 - Understand how to classify reactions of organic compounds as substitution, addition and combustion. Complete set of Chapter 7 Worksheets are available.

Companion PDF worksheet for Edexcel IGCSE Chemistry Lecture 29 - Reversible Reactions. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 3.17 - Know that some reactions are reversible and this is indicated by the symbol ⇌ in equations. Specification Point 3.18 - Describe reversible reactions such as the dehydration of hydrated copper (II) sulphate and the effect of heat on ammonium chloride. Complete set of Chapter 6 Worksheets are available.

Companion PDF worksheet for Edexcel IGCSE Chemistry Lecture 37 - Addition Polymers. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 4.44 - Know that an addition polymer is formed by joining up many small molecules called monomers. Specification Point 4.45 - Understand how to draw the repeat unit of an addition polymer, including polyethene, polypropene, polychloroethene and polytetrafluoroethene. Specification Point 4.46 - Understand how to deduce the structure of a monomer from the repeat unit of an addition polymer and vice versa. Specification Point 4.47 - Explain problems in the disposal of addition polymers. Complete set of Chapter 7 Worksheets are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.1.4 - Psychopathology. The behavioural, emotional and cognitive characteristics of phobias, depression and obsessive-compulsive disorder (OCD). Complete set of Chapter 4 Lectures are available.

Companion PDF worksheet for Edexcel IGCSE Chemistry Lecture 33 - Burning Hydrocarbons. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 4.11 - Know that a fuel is a substance that, when burned, releases heat energy. Specification Point 4.12 - Know the possible products of complete and incomplete combustion of hydrocarbons with oxygen in the air. Specification Point 4.13 - Understand why carbon monoxide is poisonous, in terms of its effect on the capacity of blood to transport oxygen. Specification Point 4.14 - Know that, in car engines, the temperature reached is high enough to allow nitrogen and oxygen from air to react, forming oxides of nitrogen. Specification Point 4.14 - Know that, in car engines, the temperature reached is high enough to allow nitrogen and oxygen from air to react, forming oxides of nitrogen. Specification Point 4.15 - Explain how the combustion of some impurities in hydrocarbon fuels results in the formation of sulphur dioxide. Specification Point 4.16 - Understand how sulphur dioxide and oxides of nitrogen contribute to acid rain. Specification Point 4.17 - Describe how long-chain alkanes are converted to alkenes and shorter-chain alkanes by catalytic cracking. Specification Point 4.18 - Explain why cracking is necessary, in terms of the balance between supply and demand for different fractions. Complete set of Chapter 7 Worksheets are available.

Powerpoint lecture and associated PDF worksheet covering the following in a modern, concise format: Specification Point 3.17 - Know that some reactions are reversible and this is indicated by the symbol ⇌ in equations. Specification Point 3.18 - Describe reversible reactions such as the dehydration of hydrated copper (II) sulphate and the effect of heat on ammonium chloride.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.2.1 - Approaches in psychology. Humanistic psychology: free will, self-actualisation and Maslow’s hierarchy of needs, focus on the self, congruence, the role of conditions of worth. The influence on counselling psychology. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture and associated PDF worksheet covering the following in a modern, concise format: Specification Point 1.18 - Understand how elements are arranged in the periodic table. Specification Point 1.19 - Understand how to deduce the electronic configurations of the first 20 elements from their positions in the periodic table. Specification Point 1.20 - Understand how to use electrical conductivity and the acid-base character of oxides to classify elements as metals or non-metals. Specification Point 1.21 - Identify an element as a metal or a non-metal according to its position in the periodic table. Specification Point 1.22 - Understand how the electronic configuration of a main group element is related to its position in the periodic table. Specification Point 1.23 - Understand why elements in the same group of the periodic table have similar chemical properties. Specification Point 1.24 - Understand why the noble gases (Group 0) do not readily react. Complete set of Chapter 2 Lessons are available.

Powerpoint lecture and associated PDF worksheet covering the following in a modern, concise format: Specification Point 2.33C - Describe how to carry out an acid-alkali titration. Complete set of Chapter 5 Lessons are available.

Powerpoint lecture and associated PDF worksheet covering the following in a modern, concise format: Specification Point 1.44 - Know that a covalent bond is formed between atoms by the sharing of a pair of electrons. Specification Point 1.45 - Understand covalent bonds in terms of electrostatic attractions. Specification Point 1.46 - Understand how to use dot-and-cross diagrams to represent covalent bonds in a variety of molecules. Specification Point 1.47 - Explain why substances with a simple molecular structures are gases or liquids, or solids with low melting and boiling points. Specification Point 1.48 - Explain why the melting and boiling points of substances with simple molecular structures increase, in general, with increasing relative molecular mass. Specification Point 1.49 - Explain why substances with giant covalent structures are solids with high melting and boiling points. Specification Point 1.50 - Explain how the structures of diamond, graphite and fullerene influence their physical properties, including electrical conductivity and hardness. Specification Point 1.51 - Know that covalent compounds do not usually conduct electricity. Complete set of Chapter 3 Lessons are available.

Powerpoint lecture and associated PDF worksheet covering the following in a modern, concise format: Specification Point 4.1 - Know that a hydrocarbon is a compound of hydrogen and carbon only. Specification Point 4.2 - Understand how to represent organic molecules using empirical formulae, molecular formulae, general formulae, structural formulae and displayed formulae. Specification Point 4.3 - Know what is meant by the terms homologous series, functional group and isomerism. Specification Point 4.4 - Understand how to name compounds relevant to this specification using the rules of IUPAC nomenclature. Specification Point 4.5 - Understand how to write the possible structural and displayed formulae of an organic molecule given its molecular formula. Specification Point 4.6 - Understand how to classify reactions of organic compounds as substitution, addition and combustion. Complete set of Chapter 7 Lessons are available.

Companion PDF worksheet for Edexcel IGCSE Biology Lecture 6 - Food Tests. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 2.9 - Practical: Investigate food samples for the presence of glucose, starch, protein and fat. Complete set of Chapter 1 Worksheets are available.

Powerpoint lecture and associated PDF worksheet covering the following in a modern, concise format: Specification Point 2.5 - Know the colours, physical states (at room temperature) and trends in physical properties of chlorine, bromine and iodine. Specification Point 2.6 - Use knowledge of trends in group 7 to predict the properties of other halogens. Specification Point 2.7 - Understand how displacement reactions involving halogens and halides provide evidence for the trend in reactivity in group 7. Specification Point 2.8C - Explain the trend in reactivity in group 7 in terms of electronic configurations. Complete set of Chapter 4 Lessons are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.2.3.1 - Scientific Processes. Aims: stating aims, the difference between aims and hypotheses. Hypotheses: directional and non-directional. Sampling: the difference between population and sample; sampling techniques including: random, systematic, stratified, opportunity and volunteer; implications of sampling techniques, including bias and generalisation. Complete set of Chapter 7 Lectures are available.