In this lesson we focus on the concept of ionisation energy and how to interpret ionisation energy trends in the periodic table. This is lesson seven in our physical chemistry series for Unit 2: Atomic Structure (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand ionisation energy and use this to rationalise trends in the Periodic Table and to deduce electronic configurations of elements. To Interpret ionisation energy data. Learning Outcomes (from the Cambridge AS Chemistry Curriculum 2019-2021): 2.3 Electrons: energy levels, atomic orbitals, ionisation energy, electron affinity d) i) explain and use the term ionisation energy ii) explain the factors influencing the ionisation energies of elements iii) explain the trends in ionisation energies across a period and down a group of the Periodic Table e) deduce the electronic configurations of elements from successive ionisation energy data f) interpret successive ionisation energy data of an element in terms of the position of that element within the Periodic Table

LESSON OBJECTIVE: Understand the mechanism of SN1 and SN2 nucleophilic substitution reactions of halogenoalkanes and describe the relative strength of the C-Hal bond. In this lesson we investigate the differences in reaction mechanism between SN1 and SN2 reactions, describe the factors that effect which one will be observed in a nucleophilic substitution reaction and investigate how the carbon-halogen bond strength effect the rate of reaction. This is lesson nine in our organic chemistry series of Unit 16: Halogen derivatives (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). Learning Outcomes: (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum) 16.1 Halogenoalkanes a) recall the chemistry of halogenoalkanes as exemplified by: (i) the following nucleophilic substitution reactions of bromoethane: hydrolysis, formation of nitriles, formation of primary amines by reaction with ammonia b) describe the SN1 and SN2 mechanisms of nucleophilic substitution in halogenoalkanes including the inductive effects of alkyl groups c) recall that primary halogenoalkanes tend to react via the SN2 mechanism; tertiary halogenoalkanes via the SN1 mechanism; and secondary halogenoalkanes by a mixture of the two, depending on structure. 16.2 Relative strength of the C-Hal bond a) interpret the different reactivities of halogenoalkanes (with particular reference to hydrolysis and to the relative strengths of the C-Hal bonds)

In this lesson we discuss the formation of sigma and pi bonds, the hybridisation of orbitals and the molecular geometries that form due to electron repulsion. This is lesson nine in our physical chemistry series for Unit 3: Chemical Bonding (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand how sigma and pi bonds form and investigate the concept of atomic orbital hybridisation. Identify molecular geometries and understand bond angles observed due to electron pair repulsion. Learning Outcomes: (from the Cambridge AS Chemistry Curriculum 2019-2021): 3.2 Covalent bonding and co-ordinate (dative covalent) bonding including shapes of simple molecules b) describe covalent bonding in terms of orbital overlap, giving σ and π bonds, including the concept of hybridisation to form sp, sp2 and sp3 orbitals (see also Section 14.3) c) explain the shapes of, and bond angles in, molecules by using the qualitative model of electron-pair repulsion (including lone pairs), using as simple examples BF3 (trigonal planar), CO2 (linear), CH4 (tetrahedral), NH3 (pyramidal), H2O (non-linear), SF6 (octahedral), PF5 (trigonal bipyramidal) d) predict the shapes of, and bond angles in, molecules and ions analogous to those specified in 3.2© (see also Section 14.3)

LESSON OBJECTIVE: Describe homolytic and heterolytic fission, understand how to draw reaction mechanisms for both and identify a number of characteristic organic reactions. In this lesson we introduce the idea of reaction mechanisms to communicate the steps in an organic reaction and the concepts of homolytic and heteroytic fission. We also summarise the main types of organic reactions (addition, elimination, substitution, hydrolysis, oxidation and reduction). This is lesson three in our organic chemistry series of Unit 14: An introduction to organic chemistry (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). Learning Outcomes: (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum) 14.2 Characteristic organic reactions a) interpret and use the following terminology associated with types of organic reactions: (i) functional group (ii) homolytic and heterolytic fission (iii) free radical, initiation, propagation, termination (iv) nucleophile, electrophile (v) addition, substitution, elimination, hydrolysis, condensation (vi) oxidation and reduction (in equations for organic redox reactions, the symbols [O] and [H] are acceptable for oxidising and reducing agents

In this lesson we discuss enthalpy changes, exothermic and endothermic reactions and enthalpy profile diagrams. This is lesson fifteen in our physical chemistry series for Unit 5: Chemical Energetics (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand the properties of exothermic and endothermic reactions and to describe the enthalpy change of various reactions under standard conditions. LEARNING OUTCOMES (from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum) 5.1 Enthalpy change, ΔH a) explain that chemical reactions are accompanied by energy changes, principally in the form of heat energy; the energy changes can be exothermic (ΔH is negative) or endothermic (ΔH is positive) b) explain and use the terms: i) enthalpy change of reaction and standard conditions, with particular reference to: formation, combustion, hydration, solution, neutralisation, atomisation ii) bond energy (ΔH positive, i.e. bond breaking)

In this lesson we discuss how catalysts can increase the rate of reaction, how to represent this on enthalpy profile diagrams and Boltzmann distributions, how to define heterogeneous and homogeneous catalyst and how enzymes catalyse biochemical reactions. This is lesson twenty six in our physical chemistry series for Unit 8: Reaction kinetics (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Describe how catalysts increase the rate of reaction and illustrate this on a Boltzmann distribution. Understand the difference between homogeneous and heterogeneous catalysts. LEARNING OUTCOMES (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum): 8.3 Homogeneous and heterogeneous catalysts including enzymes a) explain and use the term catalysis b) explain that catalysts can be homogeneous or heterogeneous c) (i) explain that, in the presence of a catalyst, a reaction has a different mechanism, i.e. one of lower activation energy (ii) interpret this catalytic effect in terms of the Boltzmann distribution d) describe enzymes as biological catalysts (proteins) which may have specificity

LESSON OBJECTIVE: Investigate infrared spectroscopy as an analytical technique and understand how to interpret IR spectra. In this lesson we investigate the analytical technique of infrared spectroscopy and how to interpret IR spectra to identify key functional groups present in a molecule. This is lesson fourteen in our organic chemistry series of Unit 22: Analytical Techniques (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). Learning Outcomes: (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum) 22.2 Infra-red spectroscopy a) analyse an infra-red spectrum of a simple molecule to identify functional groups (see the Data Booklet for the functional groups required)

In this lesson we introduce the Brønsted-Lowry theory of acids and bases, ionic equilibria and the concept of conjugate pairs. This is lesson twenty three in our physical chemistry series for Unit 7: Equilibria (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand the Brønsted-Lowry theory of acids and bases. Describe how the strength and concentration of acids and bases affects pH. LEARNING OUTCOMES (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum): 7.2 Ionic equilibria a) show understanding of, and use, the Brønsted-Lowry theory of acids and bases, including the use of the conjugate acid, conjugate base (acid-I base-I, acid-II base-II) concept b) explain qualitatively the differences between strong and weak acids and bases and the pH values of their aqueous solutions in terms of the extent of dissociation

In this lesson we discuss the solid state and the different types of lattice structures that can exist. This is lesson fourteen in our physical chemistry series for Unit 4: States of Matter (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Investigate lattice structures responsible for the solid state. LEARNING OUTCOMES (from the Cambridge AS Chemistry Curriculum 2019-2021): 4.3 The solid state: lattice structures a) describe, in simple terms, the lattice structure of a crystalline solid which is: i) ionic, as in sodium chloride and magnesium oxide ii) simple molecular, as in iodine and the fullerene allotropes of carbon (C60 and nanotubes only) iii) giant molecular, as in silicon(IV) oxide and the graphite, diamond and graphene allotropes of carbon iv) hydrogen-bonded, as in ice v) metallic, as in copper b) discuss the finite nature of materials as a resource and the importance of recycling processes c) outline the importance of hydrogen bonding to the physical properties of substances, including ice and water (for example, boiling and melting points, viscosity and surface tension) d) suggest from quoted physical data the type of structure and bonding present in a substance

In this lesson we discuss the concept of redox processes from reduction and oxidation reactions, half equations, ionic equations and how to determine oxidation states (oxidation numbers). This is lesson eighteen in our physical chemistry series for Unit 6: Electrochemistry (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand and explain redox reactions in terms of electron transfer and oxidation numbers. LEARNING OUTCOMES (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum): 6.1 Redox processes: electron transfer and changes in oxidation number (oxidation state) a) calculate oxidation numbers of elements in compounds and ions b) describe and explain redox processes in terms of electron transfer and changes in oxidation number

This lesson goes over the concepts of relative mass, the mole and Avogadro’s constant. This is lesson one in our physical chemistry series from unit 1: Atoms, Molecules and Stoichiometry (from the Cambridge International AS Chemistry Curriculum). LESSON OBJECTIVE: To understand and calculate masses of atoms and molecules based on the 12C scale, to investigate the concept of the mole and to be able to analyse mass spectra. LEARNING OUTCOMES (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum): 1.1 Relative masses of atoms and molecules a) define and use the terms relative atomic, isotopic, molecular and formula masses, based on the 12C scale 1.2 The mole and the Avogadro constant a) Define and use the term mole in terms of the Avogadro constant 1.3 The determination of relative atomic masses, Ar a) Analyse mass spectra in terms of isotopic abundances b) Calculate the relative atomic mass of an element given the relative abundances of its isotopes, or its mass spectrum.

In this lesson we discuss the particle model of states of matter, kinetic theory, the ideal gas law and the general gas equation. This is lesson twelve in our physical chemistry series for Unit 4: States of Matter (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand how to calculate and manipulate the ideal gas law equation and explain its limitations. Learning Outcomes (from the Cambridge AS Chemistry Curriculum 2019-2021): 4.1 The gaseous state: ideal and real gases and pV=nRT a) state the basic assumptions of the kinetic theory as applied to an ideal gas b) explain qualitatively in terms of intermolecular forces and molecular size: i) the conditions necessary for a gas to approach ideal behaviour ii) the limitations of ideality at very high pressures and very low temperatures c) state and use the general gas equation pV = nRT in calculations, including the determination of Mr

In this lesson we discuss how intermolecular forces arise due to the concept of electronegativity and bond polarity and other bond properties. This is lesson ten in our physical chemistry series for Unit 3: Chemical Bonding (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand the different intermolecular forces and their implications for a molecules physical properties. Explain these forces in terms of electronegativity and polarity. Learning Outcomes (from the Cambridge AS Chemistry Curriculum 2019-2021): 3.3 Intermolecular forces, electronegativity and bond properties. a) describe hydrogen bonding, using ammonia and water as simple examples of molecules containing N-H and O-H groups b) understand, in simple terms, the concept of electronegativity and apply it to explain the properties of molecules such as bond polarity, the dipole moments of molecules and the behaviour of oxides with water c) explain in terms of bond energy, bond length and bond polarity and use them to compare the reactivities of covalent bonds d) describe intermolecular forces (van der Waals’ forces) based on permanent and induced dipoles, as in, for example, CHCl3(l); Br2(l) and the liquid Group 18 element.

In this lesson we discuss the concept of Hess’ Law based on the first law of thermodynamics and how this can be used to create enthalpy cycles to determine unknown enthalpy changes. This is lesson seventeen in our physical chemistry series for Unit 5: Chemical Energetics (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand and apply Hess’ law through enthalpy cycles. Calculate enthalpy changes through bond energies and vice versa. LEARNING OUTCOMES (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum): 5.2 Hess’ Law, including Born-Haber cycles a) apply Hess’ Law to construct simple energy cycles, and carry out calculations involving such cycles and relevant energy terms, with particular reference to: i) determining enthalpy changes that cannot be found by direct experiment, e.g. an enthalpy change of formation from enthalpy changes of combustion ii) average bond energies b) construct and interpret a reaction pathway diagram, in terms of the enthalpy change of the reaction and of the activation energy

In this lesson we discuss the concept of reversible reactions, dynamic equilibrium, Le Chatelier’s principle and how Le Chatelier’s principle is linked to temperature, concentration and pressure. This is lesson twenty in our physical chemistry series for Unit 7: Equilibria (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand the concepts of a reversible reaction and dynamic equilibrium and how they apply to Le Chatelier’s principle in different contexts. LEARNING OUTCOMES (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum): 7.1 Chemical equilibria: reversible reactions, dynamic equilibrium a) explain, in terms of rates of the forward and reverse reactions, what is meant by a reversible reaction and dynamic equilibrium b) state Le Chatelier’s principle and apply it to deduce qualitatively (from appropriate information) the effects of changes in temperature, concentration or pressure on a system at equilibrium c) state whether changes in temperature, concentration or pressure or the presence of a catalyst affect the value of the equilibrium constant for a reaction.

In this lesson we discuss equilibrium constants and how to determine them using concentrations and partial pressures, and discuss how certain factors can change the value of an equilibrium constant. This is lesson twenty one in our physical chemistry series for Unit 7: Equilibria (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand and calculate equilibrium constants (Kc and Kp), determine their units and interpret how certain factors can affect its value. LEARNING OUTCOMES (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum): c) state whether changes in temperature, concentration or pressure or the presence of a catalyst affect the value of the equilibrium constant for a reaction. d) deduce expressions for equilibrium constants in terms of concentrations, Kc , and partial pressures, Kp (treatment of the relationship between Kp and Kc is not required) e) calculate the values of equilibrium constants in terms of concentrations or partial pressures from appropriate data

LESSON OBJECTIVE: Identify characteristic organic functional groups and understand the naming and drawing conventions for organic molecules. In this lesson we introduce the discipline of organic chemistry, in particular introducing different formulas to represent organic molecules, key functional groups and the rules concerning organic nomenclature. This is lesson one in our organic chemistry series for Unit 14 An introduction to organic chemistry (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). Learning Outcomes: (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum) 14.1 Formulae, functional groups and the naming of organic compounds a) interpret and use the general, structural, displayed and skeletal formulae of the following classes of compound: (i) alkanes, alkenes (ii) halogenoalkanes (iii) alcohols (including primary, secondary and tertiary) (iv) aldehydes and ketones (v) carboxylic acids, esters (vi) amines (primary only), nitriles b) understand and use systematic nomenclature of simple aliphatic organic molecules with functional groups detailed in 14.1 (a), up to six carbon atoms (six plus six for esters and amides, straight chains only) d) deduce the possible isomers for an organic molecule of known molecular formula e) deduce the molecular formula of a compound, given its structural, displayed or skeletal formula

This lesson goes over the concept of stoichiometry and how to do stoichiometric calculations that involve the reactions of masses and volumes. This is lesson three in our physical chemistry series for Unit 1: Atoms, Molecules and Stoichiometry (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: To balance equations and perform calculations using the mole concept and stoichiometric relationships. Understand the concept of a titration. LEARNING OUTCOMES (from the Cambridge AS Chemistry Curriculum 2019-2021): 1.5 Reacting masses and volumes (of solutions and gases) a) write and construct balanced equations b) perform calculations, including use of the mole concept, involving: i) reacting masses (from formulae and equations) ii) volumes of gases (e.g. in the burning of hydrocarbons) III) volumes and concentrations of solutions c) deduce stoichiometric relationships from calculations

In this lesson we focus on the electron and how it arranges itself around the nucleus in principal quantum levels, subshells and atomic orbitals. This is lesson five in our physical chemistry series for Unit 2: Atomic Structure (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand how the electron exists in principal quantum levels and subshells, to describe the relative energies of the s, p and d orbitals and to sketch the s and p orbitals. LEARNING OUTCOMES (from the Cambridge AS Chemistry Curriculum 2019-2021): 2.3 Electrons: energy levels, atomic orbitals, ionisation energy, electron affinity a) describe the number and relative energies of the s, p and d orbitals for the principal quantum numbers 1, 2 and 3 and also the 4s and 4p orbitals b) describe and sketch the shapes of s and p orbitals

LESSON OBJECTIVE: Describe and understand the properties of alkanes and characteristic reactions including combustion reactions and free-radical substitution reactions with chlorine and bromine. In this lesson we introduce the topic of hydrocarbons and in particular focus on the properties and reactions of the alkanes homologous series. This is lesson four in our organic chemistry series of Unit 15: Hydrocarbons (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). Learning Outcomes: (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum) 15.1 Alkanes a) understand the general unreactivity of alkanes, including towards polar reagents b) describe the chemistry of alkanes as exemplified by the following reactions of ethane: (i) combustion (ii) substitution by chlorine and bromine c) describe the mechanism of free-radical substitution at methyl groups with particular reference to the initiation, propagation and termination reactions