Unit 4: Rates, Equilibria and Further Organic Chemistry
Start with Concept to understand a topic, then use Question Bank to check what you know.
Your progress
Sign in to see your mastery and mistakes.
Topic 11: Kinetics
11.1The terms: i rate of reaction ii rate equation, rate=k[A]m[B]n where m and n are 0, 1 or 2 iii order with respect to
Understand the terms: i rate of reaction ii rate equation, rate=k[A]m[B]n where m and n are 0, 1 or 2 iii order with respect to a substance in a rate equation iv overall order of a reaction v rate constant vi half-life vii rate-determining step viii activation energy ix heterogeneous and homogeneous catalyst
11.2The half-life of a reaction
Be able to calculate the half-life of a reaction, using data from a suitable graph, and identify a reaction with a constant half-life as being first order
11.3Select and justify a suitable experimental technique to obtain rate data for a given reaction
Be able to select and justify a suitable experimental technique to obtain rate data for a given reaction, including: i titration ii colorimetry iii mass change iv volume of gas evolved v other suitable technique(s) for a given reaction
11.4Experiments that can be used to investigate reaction rates by: i an initial-rate method, carrying out separate experiments
Understand experiments that can be used to investigate reaction rates by: i an initial-rate method, carrying out separate experiments where different initial concentrations of one reagent are used A ‘clock reaction’ is an acceptable approximation of this method. ii a continuous monitoring method to generate data to enable concentration-time or volume-time graphs to be plotted
11.5Deduce the order (0, 1 or 2) with respect to a substance in a rate equation
Be able to deduce the order (0, 1 or 2) with respect to a substance in a rate equation, using data from: i a concentration-time graph ii a rate-concentration graph iii an initial-rate method
11.6How to: i obtain data to calculate the order with respect to the reactants (and the hydrogen ion) in the acid-catalysed
Understand how to: i obtain data to calculate the order with respect to the reactants (and the hydrogen ion) in the acid-catalysed iodination of propanone ii use these data to make predictions about species involved in the rate-determining step iii deduce a possible mechanism for the reaction
11.7Deduce the rate-determining step from a rate equation and vice versa
Be able to deduce the rate-determining step from a rate equation and vice versa
11.8Deduce a reaction mechanism
Be able to deduce a reaction mechanism, using knowledge of the rate equation and the stoichiometric equation for a reaction
11.9Knowledge of the rate equations for the hydrolysis of halogenoalkanes can be used to provide evidence for SN1 and SN2
Understand that knowledge of the rate equations for the hydrolysis of halogenoalkanes can be used to provide evidence for SN1 and SN2 mechanisms for tertiary and primary halogenoalkane hydrolysis
11.10Calculations and graphical methods to find the activation energy for a reaction from experimental data The Arrhenius
Be able to use calculations and graphical methods to find the activation energy for a reaction from experimental data The Arrhenius equation will be given if needed.
11.11The use of a solid (heterogeneous) catalyst for industrial reactions, in the gas phase, in terms of providing a surface
Understand the use of a solid (heterogeneous) catalyst for industrial reactions, in the gas phase, in terms of providing a surface for the reaction
11.12CORE PRACTICALS 9a and 9b Following the rate of the iodine-propanone reaction by a titrimetric method and investigating
CORE PRACTICALS 9a and 9b Following the rate of the iodine-propanone reaction by a titrimetric method and investigating a ‘clock reaction’ (Harcourt-Esson, iodine clock).
11.13CORE PRACTICAL 10 Finding the activation energy of a reaction
CORE PRACTICAL 10 Finding the activation energy of a reaction.
Topic 12: Entropy and Energetics
12.1That, since endothermic reactions can occur spontaneously at room temperature, enthalpy changes alone do not control whether
Understand that, since endothermic reactions can occur spontaneously at room temperature, enthalpy changes alone do not control whether reactions occur
12.2Entropy as a measure of disorder of a system in terms of the random dispersal of molecules and of energy quanta between
Understand entropy as a measure of disorder of a system in terms of the random dispersal of molecules and of energy quanta between molecules
12.3The entropy of a substance increases with temperature, that entropy increases as solid → liquid → gas and that perfect
Understand that the entropy of a substance increases with temperature, that entropy increases as solid → liquid → gas and that perfect crystals at zero kelvin have zero entropy
12.4Interpret the natural direction of change as being in the direction of increasing total entropy (positive entropy change)
Be able to interpret the natural direction of change as being in the direction of increasing total entropy (positive entropy change), including gases spread spontaneously through a room
12.5Why entropy changes occur during: i changes of state ii dissolving of a solid ionic lattice iii reactions in which there is
Understand why entropy changes occur during: i changes of state ii dissolving of a solid ionic lattice iii reactions in which there is a change in the number of moles from reactants to products
12.6The total entropy change of any reaction is the sum of the entropy change of the system and the entropy change of
Understand that the total entropy change of any reaction is the sum of the entropy change of the system and the entropy change of the surroundings, summarised by the expression: ∆Stotal = ∆Ssystem + ∆Ssurroundings
12.7The entropy change of the system for a reaction, ∆Ssystem, given the entropies of the reactants and products
Be able to calculate the entropy change of the system for a reaction, ∆Ssystem, given the entropies of the reactants and products
12.8The entropy change in the surroundings, and hence ∆Stotal
Be able to calculate the entropy change in the surroundings, and hence ∆Stotal, using the expression ∆Ssurroundings = −∆H T
12.9The feasibility of a reaction depends on: i the balance between ∆Ssystem and ∆Ssurroundings, so that even endothermic
Understand that the feasibility of a reaction depends on: i the balance between ∆Ssystem and ∆Ssurroundings, so that even endothermic reactions can occur spontaneously at room temperature ii temperature, as higher temperatures decrease the magnitude of ∆Ssurroundings so its contribution to ∆Stotal is less Students should be able to calculate the temperature at which a reaction is feasible. Students may also use ∆G = ∆H - T∆Ssystem in answers, although this approach is not a requirement of the specification.
12.10Reactions can occur as long as ∆Stotal is positive even if one of the other entropy changes is negative
Understand that reactions can occur as long as ∆Stotal is positive even if one of the other entropy changes is negative
12.11And distinguish between the concepts of thermodynamic stability and kinetic stability
Understand and distinguish between the concepts of thermodynamic stability and kinetic stability
12.12Define the terms: i standard enthalpy change of atomisation, ∆atH ii electron affinity iii lattice energy (as the exothermic
Be able to define the terms: i standard enthalpy change of atomisation, ∆atH ii electron affinity iii lattice energy (as the exothermic process for the formation of one mole of an ionic solid from its gaseous ions)
12.13Construct Born-Haber cycles and carry out related calculations
Be able to construct Born-Haber cycles and carry out related calculations
12.14A comparison of the experimental lattice energy value (from a Born-Haber cycle) with the theoretical value (obtained
Understand that a comparison of the experimental lattice energy value (from a Born-Haber cycle) with the theoretical value (obtained from electrostatic theory) in a particular compound indicates the degree of covalent bonding
12.15Polarisation of anions by cations leads to some covalency in an ionic bond, based on evidence from the Born-Haber cycle
Understand that polarisation of anions by cations leads to some covalency in an ionic bond, based on evidence from the Born-Haber cycle
12.16Define the terms ‘enthalpy change of solution, ∆solH’ and ‘enthalpy change of hydration, ∆hydH of an ion’
Be able to define the terms ‘enthalpy change of solution, ∆solH’ and ‘enthalpy change of hydration, ∆hydH of an ion’
12.17Energy cycles and energy level diagrams to calculate the enthalpy change of solution of an ionic compound
Be able to use energy cycles and energy level diagrams to calculate the enthalpy change of solution of an ionic compound, using enthalpy change of hydration and lattice energy
12.18The effect of ionic charge and ionic radius on the values of enthalpy change of hydration and the lattice energy of an ionic
Understand the effect of ionic charge and ionic radius on the values of enthalpy change of hydration and the lattice energy of an ionic compound
12.19Entropy and enthalpy changes of solution values to predict the solubility of ionic compounds and discuss trends in
Be able to use entropy and enthalpy changes of solution values to predict the solubility of ionic compounds and discuss trends in the solubility of ionic compounds covered in Unit 2
Topic 13: Chemical Equilibria
13.1Deduce an expression for Kc , for homogeneous and heterogeneous systems, in terms of equilibrium concentrations
Be able to deduce an expression for Kc , for homogeneous and heterogeneous systems, in terms of equilibrium concentrations
13.2Deduce an expression for Kp for homogeneous and heterogeneous systems, in terms of equilibrium partial pressures in atm
Be able to deduce an expression for Kp for homogeneous and heterogeneous systems, in terms of equilibrium partial pressures in atm
13.3A value, with units where appropriate, for the equilibrium constants (Kc and Kp) for homogeneous and heterogeneous
Be able to calculate a value, with units where appropriate, for the equilibrium constants (Kc and Kp) for homogeneous and heterogeneous reactions, from experimental data
13.4How, if at all, a change in temperature, pressure or the presence of a catalyst affects the equilibrium composition in
Understand how, if at all, a change in temperature, pressure or the presence of a catalyst affects the equilibrium composition in a homogeneous or heterogeneous system
13.5The value of the equilibrium constant is not affected by changes in concentration or pressure or by the addition of
Understand that the value of the equilibrium constant is not affected by changes in concentration or pressure or by the addition of a catalyst
13.6The effect of changing the temperature on the equilibrium constant (Kc and Kp) for both exothermic and endothermic reactions
Know the effect of changing the temperature on the equilibrium constant (Kc and Kp) for both exothermic and endothermic reactions
13.7The effect of temperature on the position of equilibrium is explained using a change in the value of the equilibrium
Understand that the effect of temperature on the position of equilibrium is explained using a change in the value of the equilibrium constant
13.8The effect of a change in temperature on: i the value of ∆Stotal ii the magnitude of the equilibrium constant, since ∆Stotal
Understand the effect of a change in temperature on: i the value of ∆Stotal ii the magnitude of the equilibrium constant, since ∆Stotal = R lnK
13.9Apply knowledge of the value of equilibrium constants to predict the extent to which a reaction takes place
Be able to apply knowledge of the value of equilibrium constants to predict the extent to which a reaction takes place
Topic 14: Acid-base Equilibria
14.1A Brønsted–Lowry acid is a proton donor and a Brønsted–Lowry base is a proton acceptor and that acid-base reactions involve
Understand that a Brønsted–Lowry acid is a proton donor and a Brønsted–Lowry base is a proton acceptor and that acid-base reactions involve proton transfer
14.2Identify Brønsted–Lowry conjugate acid-base pairs
Be able to identify Brønsted–Lowry conjugate acid-base pairs
14.3Define the term ‘pH’
Be able to define the term ‘pH’
14.4PH from hydrogen ion concentration
Be able to calculate pH from hydrogen ion concentration
14.5Hydrogen-ion concentration in mol dm−3 from pH using [H+] = 10^(−pH)
Calculate hydrogen-ion concentration in mol dm−3 from pH using [H+] = 10^(−pH).
14.6The difference between a strong acid and a weak acid in terms of the degree of dissociation
Understand the difference between a strong acid and a weak acid in terms of the degree of dissociation
14.7The pH of a strong acid
Be able to calculate the pH of a strong acid
14.8Deduce the expression for the acid dissociation constant, Ka, for a weak acid
Be able to deduce the expression for the acid dissociation constant, Ka, for a weak acid
14.9The pH of a weak acid from Ka or pKa values, making relevant assumptions Students will not be expected to solve quadratic
Be able to calculate the pH of a weak acid from Ka or pKa values, making relevant assumptions Students will not be expected to solve quadratic equations.
14.10Define the ionic product of water, Kw
Be able to define the ionic product of water, Kw
14.11The pH of a strong base from its concentration
Be able to calculate the pH of a strong base from its concentration, using Kw or pKw
14.12Define the terms ‘pKa’ and ‘pKw’
Be able to define the terms ‘pKa’ and ‘pKw’
14.13Analyse data from the following experiments: i measuring the pH of a variety of substances
Be able to analyse data from the following experiments: i measuring the pH of a variety of substances, including equimolar solutions of strong and weak acids, strong and weak bases, and salts ii comparing the pH of a strong and weak acid after dilution 10, 100 and 1000 times
14.14Ka for a weak acid from experimental data given the pH of a solution containing a known mass of acid
Be able to calculate Ka for a weak acid from experimental data given the pH of a solution containing a known mass of acid
14.15Draw and interpret titration curves
Be able to draw and interpret titration curves, using all combinations of strong and weak monoprotic and diprotic acids with bases, and apply these principles to diprotic acids and bases
14.16Select a suitable indicator for a titration
Be able to select a suitable indicator for a titration, using a titration curve and appropriate data
14.17What is meant by the term ‘buffer solution’
Know what is meant by the term ‘buffer solution’
14.18The action of a buffer solution
Understand the action of a buffer solution
14.19The pH of a buffer solution given appropriate data
Be able to calculate the pH of a buffer solution given appropriate data
14.20The concentrations of solutions required to prepare a buffer solution of a given pH
Be able to calculate the concentrations of solutions required to prepare a buffer solution of a given pH
14.21How to use a weak acid-strong base or strong acid-weak base titration curve to: i demonstrate buffer action ii determine Ka
Understand how to use a weak acid-strong base or strong acid-weak base titration curve to: i demonstrate buffer action ii determine Ka from the pH at the point where half the acid is neutralised/ equivalence point
14.22The importance of buffer solutions in biological environments: i buffers in cells and in blood (H2CO3/HCO-3) ii in foods
Understand the importance of buffer solutions in biological environments: i buffers in cells and in blood (H2CO3/HCO-3) ii in foods to prevent deterioration due to pH change (caused by bacterial or fungal activity)
14.23CORE PRACTICAL 11 Finding the Ka value for a weak acid
CORE PRACTICAL 11 Finding the Ka value for a weak acid.
Topic 15: Organic Chemistry: Carbonyls, Carboxylic Acids and Chirality
15.1Optical isomerism is a result of chirality in molecules with a single chiral centre
Know that optical isomerism is a result of chirality in molecules with a single chiral centre
15.2Optical isomerism results from chiral centre(s) in a molecule with asymmetric carbon atom(s) and that optical isomers
Understand that optical isomerism results from chiral centre(s) in a molecule with asymmetric carbon atom(s) and that optical isomers (enantiomers) are object and non-superimposable mirror images and be able to draw 3D diagrams of these optical isomers
15.3Optical activity is the ability of a single optical isomer to rotate the plane of polarisation of plane-polarised
Know that optical activity is the ability of a single optical isomer to rotate the plane of polarisation of plane-polarised monochromatic light in molecules containing a single chiral centre
15.4What is meant by the term ‘racemic mixture’
Know what is meant by the term ‘racemic mixture’
15.5Data on optical activity of reactants and products as evidence for SN1 and SN2 mechanisms and addition to carbonyl compounds
Be able to use data on optical activity of reactants and products as evidence for SN1 and SN2 mechanisms and addition to carbonyl compounds 15B: Carbonyl compounds Students will be assessed on their ability to:
15.6The nomenclature of aldehydes and ketones
Understand the nomenclature of aldehydes and ketones and be able to draw their structural, displayed and skeletal formulae
15.7Aldehydes and ketones: i do not form intermolecular hydrogen bonds and this affects their physical properties ii can form
Understand that aldehydes and ketones: i do not form intermolecular hydrogen bonds and this affects their physical properties ii can form hydrogen bonds with water and this affects their solubility
15.8The reactions of carbonyl compounds with: i Fehling’s or Benedict’s solution, Tollens’ reagent and acidified dichromate(VI)
Understand the reactions of carbonyl compounds with: i Fehling’s or Benedict’s solution, Tollens’ reagent and acidified dichromate(VI) ions In equations, the oxidising agent can be represented as [O]. ii lithium tetrahydridoaluminate(III) (lithium aluminium hydride) in dry ether (ethoxyethane) In equations, the reducing agent can be represented by [H]. iii HCN, in the presence of KCN, as a nucleophilic addition reaction, using curly arrows, relevant lone pairs, dipoles and evidence of optical activity to show the mechanism iv 2,4-dinitrophenylhydrazine (2,4-DNPH), as a qualitative test for the presence of a carbonyl group and to identify a carbonyl compound given data of the melting temperatures of derivatives The equation for this reaction is not required. v iodine in the presence of alkali (the iodoform test)
15.9The nomenclature of carboxylic acids
Understand the nomenclature of carboxylic acids and be able to draw their structural, displayed and skeletal formulae
15.10Hydrogen bonding affects the physical properties of carboxylic acids, in relation to their boiling temperatures
Understand that hydrogen bonding affects the physical properties of carboxylic acids, in relation to their boiling temperatures and solubility
15.11Carboxylic acids can be prepared by the oxidation of alcohols or aldehydes and the hydrolysis of nitriles
Understand that carboxylic acids can be prepared by the oxidation of alcohols or aldehydes and the hydrolysis of nitriles
15.12The reactions of carboxylic acids with: i lithium tetrahydridoaluminate(III) (lithium aluminium hydride) in dry ether
Understand the reactions of carboxylic acids with: i lithium tetrahydridoaluminate(III) (lithium aluminium hydride) in dry ether (ethoxyethane) ii bases to produce salts iii phosphorus(V) chloride (phosphorus pentachloride) iv alcohols in the presence of an acid catalyst
15.13The nomenclature of acyl chlorides and esters
Understand the nomenclature of acyl chlorides and esters and be able to draw their structural, displayed and skeletal formulae
15.14The reactions of acyl chlorides with: i water ii alcohols iii concentrated ammonia iv amines
Understand the reactions of acyl chlorides with: i water ii alcohols iii concentrated ammonia iv amines
15.15The hydrolysis reactions of esters, in acidic and alkaline solution
Understand the hydrolysis reactions of esters, in acidic and alkaline solution
15.16How polyesters, such as terylene, are formed by condensation polymerisation reactions
Understand how polyesters, such as terylene, are formed by condensation polymerisation reactions.
15.17Data from mass spectra to: i suggest possible structures of a simple organic compound given accurate relative molecular
Be able to use data from mass spectra to: i suggest possible structures of a simple organic compound given accurate relative molecular masses ii calculate the accurate relative molecular mass of a compound, given accurate relative atomic masses to four decimal places
15.18Carbon-13, (13C) NMR spectroscopy provides information about the positions of 13C atoms in a molecule
Understand that carbon-13, (13C) NMR spectroscopy provides information about the positions of 13C atoms in a molecule
15.19Data from 13C NMR spectroscopy to: i predict the different environments for carbon atoms present in a molecule, given values
Be able to use data from 13C NMR spectroscopy to: i predict the different environments for carbon atoms present in a molecule, given values of chemical shift, δ ii justify the number of peaks present in a 13C NMR spectrum in terms of the number of carbon atoms in different environments
15.20Both low and high resolution proton NMR spectroscopy to: i predict the different types of proton present in a molecule
Be able to use both low and high resolution proton NMR spectroscopy to: i predict the different types of proton present in a molecule, given values of chemical shift, δ ii relate relative peak areas, or ratio number of protons, to the relative numbers of 1H atoms in different environments iii deduce the splitting patterns of adjacent, non-equivalent protons using the (n+1) rule and hence suggest the possible structures for a molecule iv predict the chemical shifts and splitting patterns of the 1H atoms in a given molecule
15.21Chromatography separates components of a mixture using a mobile phase and a stationary phase
Know that chromatography separates components of a mixture using a mobile phase and a stationary phase
15.22Rf values from one-way chromatograms in paper and thin-layer chromatography (TLC) and understand reasons for differences
Be able to calculate Rf values from one-way chromatograms in paper and thin-layer chromatography (TLC) and understand reasons for differences in Rf values
15.23High-performance liquid chromatography, HPLC, and gas chromatography, GC, are types of column chromatography that separate
Know that high-performance liquid chromatography, HPLC, and gas chromatography, GC, are types of column chromatography that separate substances because of different retention times in the column and may be used in conjunction with mass spectrometry, in applications such as forensics or drug testing in sport