Powerpoint lecture and associated PDF worksheet covering the following in a modern, concise format: Specification Point 1.25 - Understand how to write word equations and balanced chemical equations (including state symbols). Specification Point 1.26 - Calculate relative formula masses (including relative molecular masses) from relative atomic masses. Specification Point 1.27 - Know that the mole is the unit for the amount of a substance. Specification Point 1.28 - Understand how to carry out calculations involving amount of substance, relative atomic mass and relative formula mass. Complete set of Chapter 2 Lessons are available.

Companion PDF worksheet for Edexcel IGCSE Chemistry Lecture 10 - Formulae and Calculations Part 2. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 1.29 - Calculate reacting masses using experimental data and chemical equations. Specification Point 1.30 - Calculate percentage yield. Specification Point 1.31 - Understand how the formulae of simple compounds can be obtained experimentally, including metal oxides, water and salts containing water of crystallisation. Specification Point 1.32 - Know what is meant by the terms empirical formula and molecular formula. Specification Point 1.33 - Calculate empirical and molecular formulae from experimental data. Complete set of Chapter 2 Worksheets are available.

Companion PDF worksheet for Edexcel IGCSE Chemistry Lecture 14 - Metallic Bonding. Contains short answer questions, an activity requiring lateral thinking and exam-style questions. Specification Point 1.52C - Know how to represent a metallic lattice by a 2-D diagram. Specification Point 1.53C - Understand metallic bonding in terms of electrostatic attractions. Specification Point 1.54C - Explain typical physical properties of metals, including electrical conductivity and malleability. Complete set of Chapter 3 Worksheets are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.40C - Describe an experiment to prepare a pure, dry sample of a soluble salt, starting from an acid and alkali. Specification Point 2.41C - Describe an experiment to prepare a pure, dry sample of an insoluble salt, starting from 2 soluble reactants. Specification Point 2.43C - Practical: prepare a sample of pure, dry lead (II) sulphate. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture and associated PDF worksheet covering the following in a modern, concise format: Specification Point 4.19 - Know the general formula for alkanes. Specification Point 4.20 - Explain why alkanes are classified as saturated hydrocarbons. Specification Point 4.21 - Understand how to draw the structural and displayed formulae for alkanes with up to five carbon atoms in the molecule, and to name the unbranched-chain isomers. Specification Point 4.22 - Describe the reactions of alkanes with halogens in the presence of ultraviolet radiation, limited to mono-substitution. Specification Point 4.23 - Know that alkenes contain a particular functional group (C=C). Specification Point 4.24 - Know the general formula for alkenes. Specification Point 4.25 - Explain why alkenes are classified as unsaturated hydrocarbons. Specification Point 4.26 - Understand how to draw the structural and displayed formulae for alkenes with up to four carbon atoms in the molecule, and name the unbranched-chain isomers. Specification Point 4.27 -Describe the reactions of alkenes with bromine to produce dibromoalkanes. Specification Point 4.28 - Describe how bromine water can be used to distinguish between an alkane and an alkene. Complete set of Chapter 7 Lessons are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.7.2 - Populations. Specification Point 3.7.3 - Evolution may lead to speciation. Complete set of Chapter 7 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.10 - Understand the role of enzymes as biological catalysts in metabolic reactions. Specification Point 2.11 - Understand how temperature changes can affect enzyme function, including changes to the shape of the active site. Specification Point 2.12 - Practical: Investigate how enzyme activity can be affected by changes in temperature. Specification Point 2.13 - Understand how enzyme function can be affected by changes in pH altering the active site. Complete set of Chapter 1 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.7 - Identify the chemical elements present in carbohydrates, proteins and lipids (fats and oils). Specification Point 2.8 - Describe the structure of carbohydrates, proteins and lipids as large molecules made up from smaller basic units; starch and glycogen from simple sugars, proteins from amino acids and lipids from fatty acids and glycerol. Complete set of Chapter 1 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.59 - Describe the composition of the blood: red blood cells, white blood cells, platelets and plasma. Specification Point 2.60 - Understand the role of plasma in the transport of carbon dioxide, digested food, urea, hormones and heat energy. Specification Point 2.61 - Understand how adaptations of red blood cells make them suitable for the transport of oxygen, including shape, the absence of a nucleus and the presence of haemoglobin. Specification Point 2.62 - Understand how the immune system responds to disease using white blood cells, illustrated by phagocytes ingesting pathogens and lymphocytes releasing antibodies specific to the pathogen. Complete set of Chapter 3 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.51 - Understand why simple, unicellular organisms can rely on diffusion for movement of substances in and out of the cell. Specification Point 2.52 - Understand the need for a transport system in multicellular organisms. Specification Point 2.53 - Describe the role of phloem in transporting sucrose and amino acids between the leaves and other parts of the plant. Complete set of Chapter 3 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.10 - Describe the stages in the carbon cycle, including respiration, photosynthesis, decomposition and combustion. Complete set of Chapter 6 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.90 - Describe the structure and functioning of a simple reflex arc illustrated by the withdrawal of a finger from a hot object. Specification Point 2.91 - Describe the structure and function of the eye as a receptor. Specification Point 2.92 - Understand the function of the eye in focusing on near and distant objects, and in responding to changes in light intensity. Complete set of Chapter 4 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.94 - Understand the sources, roles and effects of the following hormones: adrenaline, insulin, testosterone, progesterone and oestrogen. Complete set of Chapter 4 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 5.1 - Describe how glasshouses and polythene tunnels can be used to increase the yield of certain crops. Specification Point 5.2 - Understand the effects on crop yield of increased carbon dioxide and increased temperature in glasshouses. Specification Point 5.3 - Understand how the use of fertiliser can increase crop yield. Specification Point 5.4 - Understand the reasons for pest control and the advantages and disadvantages of using pesticides and biological control with crop plants. Complete set of Chapter 7 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.23 - Practical: Investigate photosynthesis, showing the evolution of oxygen from a water plant, the production of starch and the requirements of light, carbon dioxide and chlorophyll. Complete set of Chapter 2 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 2.28 - Describe the use of litmus, phenolphthalein and methyl orange to distinguish between acidic and alkaline solutions. Specification Point 2.29 - Understand how the pH scale can be used to classify solutions as strongly acidic, weakly acidic, neutral, weakly alkaline and strongly alkaline. Specification Point 2.30 - Describe the use of universal indicator to measure the approximate pH value of an aqueous solution. Specification Point 2.31 - Know that acids in aqueous solution are a source of hydrogen ions and alkalis in a aqueous solution are a source of hydroxide ions. Specification Point 2.32 - Know that alkalis can neutralise acids. Complete set of Chapter 5 Lectures are available.

Powerpoint lecture covering the following in a modern, concise format: Specification Point 3.19C - Know that a reversible reaction can reach dynamic equilibrium in a sealed container. Specification Point 3.20C - Know that at dynamic equilibrium the forward and reverse reactions occur at the same rate and the concentrations of reactants and products remain constant. Specification Point 3.21C - Understand why a catalyst does not affect the position of equilibrium in a reversible reaction. Specification Point 3.22C - Know the effect of changing either temperature or pressure on the position of equilibrium in a reversible reaction. Complete set of Chapter 6 Lectures are available.

Complete set of concise, modern presentations for Edexcel IGCSE Chemistry (4CH1) Chapter 3 - Bonding. Contains colour coded specification points. Four presentations included: 12 - Ionic Bonding 13 - Covalent Bonding 14 - Metallic Bonding 15 - Electrolysis

Powerpoint lecture covering the following in a modern, concise format: Specification Point 4.7.4.1 - Trophic levels. Specification point 4.7.4.2 - Pyramids of biomass. Specification Point 4.7.4.3 - Transfer of biomass. Complete set of Chapter 7 Lectures are available.