LESSON OBJECTIVE: Describe how buffer solutions regulate pH, calculate buffer solution pH and investigate their applications. Learning Outcomes: (taken from the Cambridge International AS and A Level Chemistry curriculum) 25.1 Acids and bases 5 a) define a buffer solution b) explain how a buffer solution can be made c) explain how buffer solutions control pH; use chemical equations in these explanations d) describe and explain the use of buffer solutions, including the role of HCO3- in controlling pH in blood 6 calculate the pH of buffer solutions, given appropriate data

LESSON OBJECTIVE: Understand and apply the concepts of solubility products, Ksp, the common ion effect and partition coefficients, Kpc, to a system at equilibrium Learning Outcomes: (taken from the Cambridge International AS and A Level Chemistry curriculum) 25.1 Acids and bases 7 understand and use the term solubility product, Ksp 8 write an expression for Ksp 9 calculate Ksp from concentrations and vice versa 10 a) understand and use the common ion effect to explain the different solubility of a compound in a solution containing a common ion b) perform calculations using Ksp values and concentration of a common ion 25.2 Partition coefficients 1 state what is meant by the term partition coefficient, Kpc 2 calculate and use a partition coefficient for a system in which the solute is in the same physical state in the two solvents 3 understand the factors affecting the numerical value of a partition coefficient in terms of the polarities of the solute and the solvents used

LESSON OBJECTIVE: Investigate the concept of electrode potential and describe galvanic cells. Learning Outcomes: (taken from the Cambridge International AS and A Level Chemistry curriculum) 24.2 Standard electrode potentials E⦵; standard cell potentials E⦵cell and the Nernst equation 1 define the terms: (a) standard electrode (reduction) potential (b) standard cell potential

In this lesson we discuss how to calculate enthalpy changes using the equation ΔH=–mcΔT, specific heat capacity and the concept of calorimetry as an experimental technique. This is lesson sixteen in our physical chemistry series for Unit 5: Chemical Energetics (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Understand how to calculate the enthalpy change of a reaction from experimental data obtained via calorimetry. LEARNING OUTCOMES (from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum): 5.1 Enthalpy change, ΔH c) calculate enthalpy changes from appropriate experimental results, including the use of the relationship ΔH = –mcΔT

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 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 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 the relative strength of intermolecular forces and how different types of chemical bonding will affect a species physical properties. This is lesson eleven in our physical chemistry series for Unit 3: Chemical Bonding (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Identify and rationalise the types of intermolecular forces a molecule will have and consequently describe and predict the physical properties of different species based on the type of bonding present. Learning Outcomes (from the Cambridge AS Chemistry Curriculum 2019-2021): 3.5 Bonding and physical properties a) describe, interpret and predict the effect of different types of bonding (ionic bonding, covalent bonding, hydrogen bonding, other intermolecular interactions, metallic bonding) on the physical properties of substances b) deduce the type of bonding present from given information c) show understanding of chemical reactions in terms of energy transfers associated with the breaking and making of chemical bonds

In this lesson we discuss the liquid state, phase changes and the concept of vapour pressure. This is lesson thirteen 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 the liquid state using the kinetic model and describe how particles behave during phase changes and at vapour pressure. Learning Outcomes (from the Cambridge AS Chemistry Curriculum 2019-2021): 4.2 The liquid state a) describe, using a kinetic-molecular model, the liquid state, melting, vaporisation and vapour pressure.

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 the concept of using oxidation states to determine whether a species has been reduced or oxidised, introduce the idea of oxidising and reducing agents, how to use oxidation for naming conventions and how to use oxidation numbers to balance redox reactions. This is lesson nineteen in our physical chemistry series for Unit 6: Electrochemistry (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Use oxidation numbers to determine oxidising and reducing agents, understand naming conventions and to balance chemical equations. 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) c) use changes in oxidation numbers to help balance chemical equations

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

LESSON OBJECTIVE: Describe reactions of period 3 elements with oxygen and water and investigate the periodicity of Period 3 oxides. In this lesson we link the concept of periodicity to chemical properties by investigating the formation and reactions of Period 3 oxides. This is lesson two in our inorganic chemistry series for Unit 9: The Periodic Table: chemical periodicity (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) 9.2 Periodicity of chemical properties of the elements in Period 3 a) describe the reactions, if any, of the elements with oxygen (to give Na2O, MgO, Al2O3, P4O10, SO2, SO3), chlorine (to give NaCl, MgCl2, Al2Cl6, SiCl4, PCl5) and water (Na and Mg only) b) state and explain the variation in oxidation number of the oxides (sodium to sulfur only) and chlorides (sodium to phosphorus only) in terms of their outer shell (valence shell) electrons c) describe the reactions of the oxides with water (treatment of peroxides and superoxides is not required) d) describe and explain the acid/base behaviour of oxides and hydroxides including, where relevant, amphoteric behaviour in reactions with acids and bases (sodium hydroxide only) f) interpret the variations and trends in 9.2(b), ©, (d) and (e) in terms of bonding and electronegativity g) suggest the types of chemical bonding present in chlorides and oxides from observations of their chemical and physical properties 9.1 Periodicity of physical properties of the elements in Period 3 e) explain the strength, high melting point and electrical insulating properties of ceramics in terms of their giant structure; to include magnesium oxide, aluminium oxide and silicon dioxide

LESSON OBJECTIVE: Understand the periodicity of the Period 3 chlorides and for other elements in the Periodic Table In this lesson we investigate the periodicity observed in the Period 3 chlorides and extrapolate our understanding of periodicity to other elements beyond just Period 3 in the Periodic Table. This is lesson three in our inorganic chemistry series for Unit 9: The Periodic Table: chemical periodicity (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) 9.2 Periodicity of chemical properties of the elements in Period 3 a) describe the reactions, if any, of the elements with oxygen (to give Na2O, MgO, Al2O3, P4O10, SO2, SO3), chlorine (to give NaCl, MgCl2, Al2Cl6, SiCl4, PCl5) and water (Na and Mg only) b) state and explain the variation in oxidation number of the oxides (sodium to sulfur only) and chlorides (sodium to phosphorus only) in terms of their outer shell (valence shell) electrons e) describe and explain the reactions of the chlorides with water f) interpret the variations and trends in 9.2(b), ©, (d) and (e) in terms of bonding and electronegativity g) suggest the types of chemical bonding present in chlorides and oxides from observations of their chemical and physical properties 9.3 Chemical periodicity of other elements a) predict the characteristic properties of an element in a given group by using knowledge of chemical periodicity b) deduce the nature, possible position in the Periodic Table and identify of unknown elements from given information about physical and chemical properties

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

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 calculations with equilibrium constants using the ‘RICE table’ method and how equilibria can effect industrial chemical production, specifically in the Haber process and the Contact process. This is lesson twenty two in our physical chemistry series for Unit 7: Equilibria (from the Cambridge International AS Chemistry Curriculum (9701) 2019-2021 curriculum). LESSON OBJECTIVE: Apply the concepts of equilibria and equilibrium constants to laboratory procedures, including industrially with the Haber and Contact processes. LEARNING OUTCOMES (taken from the Cambridge International AS and A Level Chemistry (9701) 2019-2021 curriculum): 7.1 Chemical equilibria: reversible reactions, dynamic equilibrium f) calculate the quantities present at equilibrium, given appropriate data (such calculations will not require the solving of quadratic equations) g) describe and explain the conditions used in the Haber process and the Contact process, as examples of the importance of an understanding of chemical equilibrium in the chemical industry

LESSON OBJECTIVE: Explain the trends observed across the periodic table including atomic radius, ionic radius, melting point, electrical conductivity and first ionisation energy. In this lesson we discuss the concept of periodicity and justify the trends we observe in a number of physical properties as we move across the Period 3 elements. This is lesson one in our inorganic chemistry series for Unit 9: The Periodic Table: chemical periodicity (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) 9.1 Periodicity of physical properties of the elements in Period 3 a) describe qualitatively (and indicate the periodicity in) the variations in atomic radius, ionic radius, melting point and electrical conductivity of the elements (see the Data Booklet) b) explain qualitatively the variation in atomic radius and ionic radius c) interpret the variation in melting point and electrical conductivity in terms of the presence of simple molecular, giant molecular or metallic bonding in the elements d) explain the variation in first ionisation energy (see the Data Booklet)

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