Al Chemistry Syllabus

POCA Wong Siu Ching Sec. Sch.

F.6 Chemistry Teaching Schedule (2000-01) Textbook: New Way Chemistry for Hong Kong A-level (Book1, 2 and 3) Cycle Date

Syllabus 1. Atom, Molecules and Stoichiometry

Explanatory Notes

References in texts

Protons, neutrons and electrons as constituents of the atom.

Chapter 1

Remark

1.1 The atomic structure The relative masses and charges of a proton, neutron and electron. The atomic nucleus. Relative size of the atom and atomic nucleus. 1.2 Radioactivity Nature of α,β particles, and ofγradiation. Equations for nuclear reactions. Uses of isotopes in leak detection, radiotherapy, nuclear power and as tracers. (Underlying principles and instrumentation are not required.) 1.3 Relative isotopic, atomic and molecular masses

A brief account of the mass spectrometer in determining relative isotopic, atomic and molecular masses (instrumental details and mathematical treatment of the mass spectrometer, and the use of fragmentation in structure determination are not required.)

1.4 The mole concept The mole and the Avogadro constant.

Chapter 2

Molar volume of gases at R.T.P. (room temperature and pressure) and S.T.P. (standard temperature and pressure). Ideal gas equation, pV=nRT

1

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

and its application to the relative molecular mass determination. (Non-ideal behaviour of real gases and kinetic theory are not required.) Partial pressure of gas and its relationship to mole fraction. 1.5 The Faraday and the mole The Faraday as the quantity of electricity of one mole of electrons. Relationship between the mass liberated and the quantity of electricity passed in electrolysis. 1.6 Empirical and molecular formulae Derivation of empirical formula using combustion data or composition

Chapter 3

by mass. Molecular formula derived from empirical formula and relative molecular mass. 1.7 Chemical equations and stoichiometry The stoichiometric relationship between reactants and products in a reaction. Calculation involving

2.

i.

reacting masses

ii.

volumes of gases, and

iii.

concentrations and volumes of solutions

The Electronic Structure of Atoms and the Periodic Table

2.1 Atomic emission spectra and electronic structure of atoms

Characteristics of the emission spectrum of atomic hydrogen.

Chapter 4

Interpretation of the spectrum using the relationship, E=hυleading to the

2

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

idea of discrete energy levels. Convergence limits and ionization. (Calculation are not required). An awareness of the uniqueness of atomic emission spectra. 2.2 Electronic structure, ionization enthalpies, electron shell

Plots of the following graphs to introduce shells and sub-shells: i.

successive ionization enthalpies for a particular element, and

ii.

first ionization enthalpies against atomic numbers (up to Z=20).

Chapter 5

(Experimental determination of ionization enthalpy is not required). 2.3 Atomic orbitals

An awareness of the wave nature of electrons, and that electrons are not localized in fixed orbits. An atomic orbital as a representation of a region within which there is a high probability of finding an electron. The designation of s, p and d orbitals. The number and relative energies of the s, p and d orbitals for the principal quantum numbers 1,2 and 3, and also of 4s and 4p orbitals. Shapes of s and p orbitals only. (The uncertainty principle is not required.)

2.4 Electronic configurations of atoms

Building up of electronic configurations based on three principles: i.

electrons enter the orbitals in order of ascending energy (Aufbau principle),

ii.

orbitals of the same energy must be occupied singly before pairing occurs (Hund’s rule), and

3

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

iii.

electrons occupying the same orbital must have opposite spins (Pauli’s exclusion principle).

Electronic configurations in relation to the Periodic Table

Electron configurations of isolated atoms from H to Kr. Electron configurations of atoms represented by i.

Notation using 1s, 2s, 2p, etc., e.g. Fe (ground state) 1s22s2sp63s23p63d64s2

ii. 2.5 The Periodic Table and the atomic properties of the elements

‘electrons-in-boxes’ diagram

The Periodic Table, showing the s-, p-, d- and f-blocks. Interpretation of the trends of ionization enthalpies and atomic radii of the elements in the Periodic Table.

3.

Energetics

3.1 Energy changes in chemical reactions Conservation of energy. Endothermic and exothermic reactions and their Chapter 6 relationship to the breaking and forming of bonds. 3.2 Standard enthalpy changes

Enthalpy change, ΔH, as heat change at constant pressure. Standard enthalpy change of: i.

neutralization,

ii.

solution,

iii.

formation, and

iv.

combustion

4

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Experimental determination of enthalpy changes of reactions, limited to simple calorimetric method. (Bomb carlorimeter is not required). 3.3 Hess’s law

Use of Hess’s law to determine enthalpy changes that are not easily obtainable by experiment. Enthalpy level diagrams. Calculations involving enthalpy changes of reactions.

4.

Mid-term test

Bonding and Structure

4.1 The nature of forces holding atoms together 4.2 Ionic bonding

Electrostatic interactions between electrons and nuclei leading to

Chapter 7

different types of bonding. Formation of ions – the tendency for atoms of elements in Groups I, II, VI and VII to attain electronic configurations of noble gases. ‘Dot and cross’ diagrams for simple ionic compounds.

Energetics of formation of ionic

Born-Haber cycles for the formation of ionic compounds in terms of

compounds

enthalpy changes of atomization and ionization, electronic affinities and lattice enthalpies. (Electronic affinity is the enthalpy change when one mole of electrons is added to one mole of atoms or ions in the gaseous state, e.g. O(g) + e-  O-(g) ΔH = -141 kJ mol-1 O-(g) + e-  O2-(g) ΔH= +791 kJ mol-1;

5

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Lattice enthalpy is the enthalpy change when one mole of an ionic compound is formed from its constituent ions in the gaseous state, e.g. Na+(g) + Cl-(g)  NaCl(s) ΔH = -781 kJ mol-1 Stoichiometry of ionic compounds

Consideration in terms of electronic configurations and enthalpy changes of formation.

Ionic crystals

Extended three-dimensional structures of ionic compounds limited to sodium chloride and caesium chloride. Unit cells and coordination numbers. (Calculations involving ionic radii in a unit cell are not required.)

Ionic radii

Comparison of sizes of ions with their parent atoms. Comparison of sizes of isoelectronic particles.

4.3 Covalent bonding

Formation of covalent bonding – sharing of electron pairs.

Chapter 8

The simple idea of the overlapping of atomic orbitals. ‘Dot and cross’ diagrams for simple molecules, e.g. CH4, NH3, H2O, HF. Octet rule and its limitation, e.g. PCl5 and BF3. Dative covalent bonding

Treated as a special example of covalent bonding, illustrated by H3N->BF3. The simple idea of the overlapping of an empty orbital with

6

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

an orbital occupied by a lone pair of electrons. Bond enthalpies, bond lengths and

Estimation of bond enthalpies using data from energetics.

covalent radii

Bond enthalpies as a comparison of the strength of covalent bonds. Relationship between covalent bond enthalpies and bond lengths as illustrated by hydrogen halides. Addition of covalent radii to give approximate covalent bond lengths as illustrated by simple molecules.

The shapes of covalent molecules

The shapes of simple molecules and polyatomic ions explained in terms

and polymeric ion

of the repulsion between electron pairs(as illustrated by BF3, CH4, H2O, PCl5, SF6, NH4+ and NH2-). The directional nature of covalent bonds. Bond angles.

Multiple bonds

Comparison of bond lengths and bond enthalpies leading to the idea of multiple bonds, illustrated by ethane and ethyne. Shapes of carbon dioxide and sulphur dioxide molecules explained in terms of repulsion between electron pairs.

Covalent crystals

Exemplified by diamond, graphite and quartz.

4.4 Bonding intermediate between ionic

Chapter 9

7

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

and covalent Incomplete electron transfer in ionic Comparison of the experimental lattice enthalpies of e.g. silver halides compounds

and zinc sulphide, with the theoretical values calculated on a completely ionic model leading to the idea of polarization of ions. (Calculation of the theoretical value of lattice enthalpy is not required).

Polarity of covalent bond

Displacement of an electron cloud leading to the formation of a polar covalent bond. Dipole moment as evidence for bond polarization in simple molecules. (Calculation of dipole moment is not required.) Unequal sharing of bonded electron pair(s) explained in terms of the electronegativity difference between bonded atoms. Electronegativity (Pauling’s scale) introduced as an arbitrary measure of an atom’s tendency in a molecule to attract electrons. (The formal definition of electronegativity and its experimental determination are not required.)

4.5 Metallic bonding

Metallic bonding illustrated by a model of cationic lattice and mobile

Chapter 10

valence electrons. Simple explanation of the metallic conduction of electricity based on the model. Strength of metallic bond in terms of metallic radii and the number of valence electron(s) per atom.

8

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Metallic crystals

Cross-packed and open structures: hexagonal and cubic close-packed, and body-centred cubic structures. Unit cells and coordination numbers. (Calculations related to atomic radii in a unit cell are not required.)

4.6 Intermoleular forces Van der Waals’ forces

Brief discussion of the origin of van der Waals’ forces in terms of

Chapter 11

permanent, instantaneous and induced dipoles. Comparison of the covalent and van der Waals’ radii of non-metals to indicate the relative strength of the covalent bonds and van der Waals’ forces. Molecular crystals

Exemplified by iodine and carbon dioxide.

Hydrogen bonding

A study of the boiling points and enthalpy changes of vaporization of the hydrides of Groups IV, V, VI and VII and compounds like alcohols and carboxylic acids leading to the idea of hydrogen bonding. Nature of hydrogen bonding. Relative strength of van der Waals’ forces and hydrogen bonding. Hydrogen bonding in ice, proteins and DNA (deoxyribonucleic acid)

4.7 The relationship between structures

Differences in physical properties (viz. melting and boiling points,

and properties of materials

electrical conductivity, hardness and solubility) between ionic

9

Chapter 12

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

compounds, covalent substances and metals 5.

Chemical Kinetics

5.1 Rates of chemical reactions

The meaning of the rate of a chemical reaction.

Chapter 13

Following a reaction by chemical and physical methods, viz. following the change in amount of reactant/product by titration, determining the volume of gas formed, or colorimetric measurement of light intensity at different times. (The theory of colorimetry is not required.) 5.2 Factors influencing reaction rate

Effects of concentration, temperature, pressure, surface area, catalyst and Term examination light on reaction rate.

5.3 Rate equations and order of reactions Simple rate equations determined from experimental results.

Chapter 14

Zeroth, first and second order reactions. Rate constants. Half-life of a first order reaction. Radioactive decay as a typical example of a first order reaction. Carbon-14 dating in the estimation of the age of an archaeological specimen. Cabon-14 dating in the estimation of the age of an archaeological specimen. Calculations involving rate equations. (Deriving of integral forms of rate equations is not required.)

10

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

5.4 The effect of temperature change on Explanation of the effect of temperature change on reaction rate in terms Chapter 15 reaction rate

of activation energy. Application of the Arrhenius equation k = A exp(-Ea/RT) to determine the activation energy of a reaction. (Derivation of the Arrhenius equation is not required.)

5.5 The interpretation of rates of gaseous Distribution of molecular speeds in a gas. (Zartmann experiment and reactions at molecular level

calculations involving molecular speeds are not required.) Graphical representation of the Maxwell-Boltzmann distribution and its variation with temperature. Simple collision theory. (Qualitative treatment only.)

5.6 Energy profile

Energy profile as a representation of the changes in potential energy during a reaction. Simple stage and multi-stage reactions. The rate determining step in a multi-stage reaction.

5.7 Catalysts and their effect on reaction Catalysts can change the rate of a reaction by providing an alternative rates

pathway for the reaction.

Homogeneous and heterogeneous

Acid-catalysed esterification as an example of homogeneous catalysis.

catalysis

Effect of manganese(IV) oxide on the decomposition of hydrogen

11

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

peroxide as an example of heterogeneous catalysis. Applications of catalysts

The use of catalysts in Contact and Haber processes, and the hydrogenation of unsaturated oils. Catalytic converters in car exhaust systems. An awareness that enzymes are example of biological catalysts.

6.

Chemical Equilibria

6.1 Dynamic equilibrium

Reversible reactions.

Chapter 16

Dynamic nature of chemical equilibrium. Characteristics of chemical equilibrium. The equilibrium law

Equilibrium constants expressed in terms of concentration (Kc) and partial pressure (Kp). Simple calculations of Kc and Kp. (The quantitative relationship between Kc and Kp is not required.)

The effect of changes in

Le Chatelier’s principle. Changes in concentration and pressure result in

concentration, pressure and

the adjustment of the system without changing the value of equilibrium

temperature on equilibria

constant, K; a change in temperature results in the adjustment of the system to a new equilibrium constant. Reaction of temperature and the value of K for exothermic and endothermic reactions illustrated by the equation, ln K = constant – ΔH/RT (Derivation of the equation is not required.)

12

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Simple calculation on equilibrium composition involving changes in concentration/pressure.

6.2 Acid-base equilibria

Bronsted-Lowry theory

Chapter 17

Concepts of acid/base Dissociation of water

Ionic product of water, Kw

pH and its measurement

The use of indicators and pH meters to measure pH. (The theory and instrumentation of pH meters are not required.)

Strong and weak acids/bases

Dissociation constants for weak acids (Ka) and weak bases (Kb). Use of Ka and Kb (pKa and pKb) values to compare the strength of weak acids or weak bases. Calculations involving pH, Ka and Kb. (For dissociation involving more than one step, calculations are limited to one of these steps only.)

Buffers

Principle of buffer action. Calculations involving the composition and

Chapter 18

pH of buffer solutions. Indicators

Simple theory of acid-base indicators and pH range of their colour changes.

13

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Acid-base titrations

pH titration curves and the choice of indicators.

6.3 Redox Equilibria Redox reactions

Redox reactions in terms of electron transfer. Oxidation states. Balancing Chapter 19 redox equations.

Electrochemical cells

E.m.f. measurement of electrochemical cells of metal-metal ion systems. Chapter 20 E.m.f. values to compare the relative tendencies of half cells to release or gain electrons. Other systems involving non-metal ions. (e.g. I2(aq) , 2I-(aq) | Pt), ions in different oxidation states(e.g. Fe3+(aq), Fe2+(aq)|Pt) and metal-metal salt (e.g. PbSO(s), [Pb(s) + SO42-(aq)]|Pt). Cell equations. IUPAC convention in writing cell diagrams.

Electrode potentials

The standard hydrogen electrode as a reference. The convention of standard reduction potentials is adopted. The electrochemical series (redox potential series). Use of the standard electrode potential (E) values to compare the strength of oxidizing/reducing agents, and to calculate the e.m.f. of cells. Prediction of the feasibility of redox reactions from electrode potential values and the limitation of this approach due to kinetic factor.

14

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Secondary cell and fuel cell

Lead-acid accumulator and the hydrogen-oxygen fuel cell: structure, electrochemical processes and uses.

Corrosion of iron and its prevention

The electrochemical process involved in rusting. Prevention of corrosion by coating and cathodic protection. Socioeconomic implication of corrosion and prevention.

7.

Phase Equilibrium

7.1 One component systems

The pressure – temperature diagrams of water and carbon dioxide.

Chapter 21

(Phase rule is not required.) 7.2 Two component systems

Studies limited to phase diagrams for mixtures of two miscible liquids:

i.

Chapter 22

Vapour pressure against mole fraction (with temperature constant), and

ii. Ideal systems

Boiling point against mole fraction (with pressure constant).

Rauolt’s law. The characteristic properties of an ideal system explained in terms of molecular interactions.

Non-ideal systems

Positive and negative deviations from Rauolt’s law explained in terms of molecular interactions. Enthalpy changes on mixing as evidence for nonideal behaviour. Azeotropic mixtures.

15

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Fractional distillation

Explanation of the principle of fraction distillation using the boiling point – composition curve. Application of fraction distillation in oil refining.

7.3 Partition of a solute between two

Partition coefficient of a non-volatile solute distributed between two

phases

immiscible liquids. (Calculations involving dissociation or association of

Chapter 23

solute are not required.) Application to solvent extraction. Paper chromatography as an application of partition. Rf value.

Term test

12. Fundamentals of Organic Chemistry 12.1 Natural sources of organic

Alkanes, alkenes and aromatic hydrocarbons from crude oil and coal.

compounds

Carbohydrates, proteins and fats in living organisms.

12.2 The unique nature of carbon

Ability of carbon to catenate leading to the existence of a vast number of

Chapter 24

carbon compounds. 12.3 Functional groups and homologous

Studies limited to the following functional groups:

series

C=C, C≡C, -X, -OH, -O-, -CHO, C=O, -COOH, -NH2, -NHR, -NR2, -CN, -COOR, -COX, -CONH2 and (-CO)2O. Effects of functional groups and the length of carbon chains on physical properties of compounds in homologous series.

16

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

12.4 Structures and shapes of

Chapter 25

hydrocarbons Saturated hydrocarbons

The tetrahedral arrangement of the bond electron pairs around a carbon atom explained in terms of repulsion between electron pairs and in terms of sp3 hybridized orbitals. (Conformation is not required.)

Unsaturated hydrocarbons

Formation of the C=C and C≡C bonds explained in terms of sp2 and sp hybridized orbitals respectively. σandπbonds. Shapes associated with sp2 and sp hybridized carbon atoms.

Aromatic hydrocarbons

Shape of the benzene molecule. Delocalization of π-electrons in benzene giving rise to a unique class of compounds which are chemically different from alkenes.

12.5 Systematic nomenclature

Systematic nomenclature limited to compounds containing carbon chains Chapter 26 of not more than eight carbon atoms.

12.6 Isomerism Structural isomerism

Chapter 27 Isomers containing the same functional group and isomers containing different functional groups.

17

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Geometrical isomerism

Rigidity of C=C bond leading to cis/trans isomers. Geometrical isomers limited to acyclic compounds containing one C=C.

Enantiomerism

Studies limited to structures with one chiral cabon. (Absolute configuration and resolution of racemic mixtures are not required.)

12.7 Structure determination of organic compounds

Calculation of empirical formula from analytical data (linked with

Chapter 28

section 1.6). Molecular formula. Structure deduced from reactions of functional groups and physical properties. An awareness that spectroscopic methods such as infrared spectroscopy and nuclear magnetic resonance (NMR) can provide information about the structure of a molecule.

Use of infra-red (IR) spectrum in the identification of functional groups

IR spectrum and its use in the identification of the following groups: C-H, O-H, N-H, C=C, C≡C, C=O and C≡N. (Instrumentation is not required.)

13. Chemistry of Organic Compounds Mechanisms other than those mentioned specifically are not required.

13.1 Alkanes

Crude oil as a source of alkanes.

Chapter 30

Chemical principles and economic importance of fractional distillation

18

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

(linked with 7.2) and cracking process (Industrial detail are not required.) Combustion of alkanes. Chlorination of alkanes as light-initiated chain reactions. Mechanism of the chlorination of methane. 13.2 Alkenes Addition reactions

Chapter 31 Reactions of alkenes with bromine (aqueous and non-aqueous), hydrogen bromide and sulphuric(VI) acid. Mechanism of the electrophilic addition of hydrogen bromide to alkenes. Markownikoff’s rule. Catalytic hydrogenation and its application in the hardening of oils.

Ozonolysis

Conditions and reaction products. Use in the determination of positions of the carbon-carbon double bonds in alkenes.

Polymerization of alkenes

Formation of poly(ethene), poly(propene) and poly(phenylethene). Mechanism of free radical polymerization of ethane.

13.3 Aromatic hydrocarbons

Benzene and methylbenzene.

Chapter 32

Stability of the benzene ring: comparison of the enthalpy changes of hydrogenation and combustion for benzene and cyclohexene leading to the concept of increased stability in a delocalized system. Resistance of benzene to oxidation and addition reactions.

19

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Substitution

Nitration, halogenation, sulphonation and alkylation. (limited to monosubstitution only) Reaction with potassium manganate(VII)

Oxidation of alkylbenzene 13.4 Halogeno-compounds

Primary, secondary and tertiary haloalkanes, halobenzene. Reactions with sodium hydroxide, potassium cyanide and ammonia.

Term examination Chapter 33

(Experimentation involving potassium cyanide should not be attempted.) Nucleophilic substitution reactions

Comparison of rates of hydrolysis of haloalkanes and halobenzene. Mechanism of SN1 and SN2 as exemplified by substitution with –OH group. (Linked with 5.6)

Elimination reaction

Reaction of haloalkanes with alcoholic sodium hydroxide to form alkenes and alkynes.

Uses of halogeno-compounds

Halogeno-compounds as solvents in dry-cleaning and as raw materials in the manufacture of poly(chloroethene) and poly(tetrafluoroethene).

13.5 Hydroxy compounds

Primary, secondary and tertiary alcohols; phenol.

20

Chapter 34

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Acidic properties of hydroxy

Comparison of the acidic properties between alcohols and phenol.

compounds Reactions of alcohols

Reactions include halide formation, alkoxide formation, oxidation, dehydration, esterification and triiodomethane formation. Distinction between primary, secondary and tertiary alcohols.

Reactions of phenol

Reactions with sodium and sodium hydroxide. Esterification.

Uses of alcohols

Alcohols as solvents. Ethanol in beverages and as a motor fuel blending agent. Ethane-1.2-diol as an anti-freeze and a raw material in the manufacture of terylene.

Cycle Date

Syllabus Carbonyl compounds

Explanatory notes Structures of aldehydes and ketones. Benzaldehyde and phenylethanone as aromatic carbonyl compounds.

21

Reference in text

Suggested Experiments

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Reactions with hydrogen cyanide and sodium hydrogensulphate( IV). Nucleophilic addition reactions

(Experimentation involving hydrogen cyanide should not be attempted.) Mechanism of the addition of hydrogen cyanide to carbonyl compounds. Use of the reaction with sodium hydrogensulphate( IV) in the purification of carbonyl compounds.

Reactions with hydroxylamine and 2, 4- dinitrophenylhydrazine.

Identification of a carbonyl compound by

Addition- elimination (condensation) reactions Oxidation of aldehydes with acidified dichromate( VI), Tollens' reagent and Oxidation and reduction

preparing its derivative.

Fehling's reagent. Resistance of ketones to oxidation. Reduction of aldehydes and ketones with sodium tetrahydridoborate (sodium

Investigation of the reactions of aldehydes and

borohydride) and lithium tetrahydridoaluminate (lithium aluminium hydride).

ketones.

Formation of triiodomethane as a test for compounds containing a CH 3 CO − group or a CH 3 CH( OH) − group.

Methanal in the manufacture of urea- methanal resin. Uses of carbonyl compounds

Propanone as a solvent and a raw material in the manufacture of perspex.

13.7 Carboxylic acids and their derivatives

Structures of carboxylic acids, acyl chlorides, anhydrides, amides and esters.

22

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

The formation of carboxylic acid

Hydrolysis of nitriles. Oxidation of alcohols, aldehydes and alkylbenzenes.

Reactions of carboxylic acids

Formation of salts, acyl chlorides, anhydrides, amides and esters. Reduction with

Investigation of the reactions of carboxylic

lithium tetrahydridoaluminate.

acids. Preparation of an ester.

Acidity of carboxylic acids

Comparison of the acidity of carboxylic acids with alcohols. Influence of substituents, viz. alkyl and chloro groups, on acidity.

Reactions of acyl chlorides and Anhydrides

Reactions with water, alcohols, ammonia and amines.

Reactions of amides

Hydrolysis, dehydration, Hofmann degradation and reduction with lithium tetrahydridoaluminate.

Reactions of esters

Acid and base hydrolyses. Reduction with lithium tetrahydridoaluminate.

Analysis of commercial aspirin tablets.

Uses of carboxylic acids and their derivatives Benzoic acid and benzoates as food preservatives. Polyamides and polyesters as synthetic fibres e. g. nylon 6. 6 and terylene. Uses of esters as solvents and flavourings.

Nitrogen compounds

Primary, secondary and tertiary aliphatic amines, phenylamine and amino acids.

23

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

The formation of amines Primary amines from Primary, secondary and tertiary aliphatic amines, and quaternary ammonium nitriles and amides.

compounds by alkylation. Phenylamine from nitrobenzene.

Base properties of amines

Salt formation. Comparison of the basic strength of ammonia, primary aliphatic amines and phenylamine.

Reaction of amines

Reactions with ethanoyl chloride and benzoyl chloride. Reaction with nitric( III)

.

acid limited to primary amines only. Coupling reaction of benzenediazonium ion

Investigation of the reactions of amines.

with naphthalen- 2- ol. (Test to distinguish primary, secondary and tertiary amines is not required.)

Uses of amines and their derivatives

Azo- compounds as dyes in dyeing industries. Amine derivatives as drugs.

Amino acids

Amino acids (e. g. aminoethanoic acid and 2- amino- propanoic acid) as bifunctional compounds having both acidic and basic characteristics. Zwitterion. Dipeptides and polypeptides as dimers and polymers of amino acids. (Methods of formation of polypeptides are not required.)

14. Chemistry and Society

14.1 Chemistry and the environment

24

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

(a) Air pollution

Some air pollutants

Carbon monoxide, sulphur dioxide, nitrogen oxides, hydrocarbons, ozone and particulates. Combustion of fossil fuels as the main source of air pollutants.

The effects of polluted air on the environment The harmful effects of pollutants depend on their concentrations and the duration of exposure to the pollutants. Parts per million (ppm) as one way of indicating concentrations of pollutants. Acid rain and photochemical smog: their formation and effects on the environment.

The ozone layer and chlorofluoro- carbons

Sources and properties of ozone. The desirability of ozone in the stratosphere.

Project work on air pollution, e.g. acid rain,

Chlorofluorocarbons as aerosol propellants, solvents for the cleaning of

smog or ozone depletion.

electronic components and metals, refrigerants, and blowing agents in foam plastic manufacturing. Causes for the accumulation of chlorofluorocarbons in the stratosphere. The free radical chain reactions involved with chlorofluorocarbons leading to the depletion of the ozone layer. Control of the ozone depletion problem. Possible alternatives for chlorofluorocarbons.

(b) Water pollution

The causes of water pollution and its effects

The adverse effects on water quality due to livestock waste, oil spillages,

on the environment

residues of pesticide, detergents in sewage, and industrial effluents.

25

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Water quality

An awareness that oxygen dissolved in water is necessary for aquatic life.

Determination of dissolved oxygen in water

Dissolved oxygen (DO) as an indicator of oxygen content in water, expressed as

samples.

percentage saturation or mg dm –3 . Biochemical oxygen demand (BOD) as an indicator of the extent of water pollution.

(c) Solid waste

Plastics, paper and metals. Disposal of solid waste by landfilling and ncineration. Pollution problems associated with the disposal of plastics. Development of degradable plastics and recycling of plastics as possible solutions to pollution problems.

(d) Pollution control in Hong Kong

Measures to improve air quality: use of unleaded petrol and installation of

Visit to

catalytic converters in car exhaust systems, limitation of sulphur content in fuels,

a.

the Environment Resource Centre,

desulphurization of flue gas, installation of electrostatic precipitators and

b.

the Chemical Waste Treatment Centre, or

installation of low nitrogen oxide burners in power plants.

c.

a sewage treatment plant.

Measures to improve water quality: screening, sedimentation and digestion of pollutants by micro- organisms in the treatment of sewage; physical and chemical methods, and incineration in the treatment of chemical waste from industry and laboratories. (Technical details of the above treatment processes are not required.) Measures to reduce solid waste:

26

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

reuse/ recycling of paper, plastics and metals to minimize waste and save resources. 14.2 Chemistry and food (a) Principal components of food Proteins

Proteins as macromolecules made up of amino acids via peptide linkages.

Separation of amino acids by paper

Hydrolysis of proteins. Separation of amino acids by paper chromatography.

chromatography.

(Linked with Sections 7.3 and 13.8)

Carbohydrates

Classification into monosaccharide, disaccharide and polysaccharide. Open chain

Investigation of the hydrolysis of sucrose and

and ring structures of glucose and fructose. Glycosidic linkage in carbohydrates.

testing for reducing sugars.

Hydrolysis of sucrose and starch. Fehling's test to distinguish between reducing and non- reducing sugars.

Fats and oils

Fats and oils as esters of propane- 1, 2,3- triol and fatty acids. Hydrolysis of fats and oils (Link with Section 13.7). Use of iodine value tocomparethe degree of unsaturation. Hardening of vegetable oils. (Link with Section 13.2) Hydrolytic and oxidative rancidity.

(b) Food preservation

The need to preserve food

Prevention of food spoilage due to microbial activities and chemical changes.

Investigation of the effects of air and

Principles and techniques of food preservation Principles of food preservation:

27

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

killing of micro- organisms, inhibition of microbial growth, retardation of

preservatives on apple browning.

chemical changes by removing moisture, altering temperature, changing pH, and the use of osmotic process and chemical additives. Common techniques include heat treatment, irradiation, drying, dehydration, refrigeration, canning, sugaring, salting and chemical preservation such as meat- curing, pickling and the use of food additives.

(c) Food additives

Food additives to serve as preservatives (e. g. nitrates( III), nitrates( V), sulphur

Library search on different functions of

dioxide, sulphates( IV), benzoic acid and benzoates) and antioxidants (e. g.

common food additives.

BHA (butylated hydroxyanisole) and BHT (butylated hydroxytoluene)), to

Analysis of sulphur dioxide content in wine.

enhance the flavour (e. g. MSG (monosodium glutamate), saccharin), texture (e. g. emulsifying agents), appearance (e. g. colouring agents) or nutritional value (e. g. vitamins) of food. Principle of BHA/ BHT as antioxidant to retard atmospheric oxidation of oils and fats.

The possible menace of

The side effects of MSG, the toxicity of nitrates( III) and sulphur dioxide, and

food additives

the potent carcinogenic nature of nitrates( III) and saccharin.

Debate on the use of food additives.

An awareness that the use of food additives is monitored by research findings and by legislation.

28

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

8.

Periodic Properties of the Elements in the Periodic Table

8.1 Periodic variation in physical properties of Variations in first ionization enthalpies (linked with Section 2. 2), atomic radii, the elements H to Ar

electronegativities and melting points. Interpretation of these variations in terms of structure and bonding.

8.2 Periodic relationship among the oxides,

Bonding and stoichiometric composition of the hydrides, oxides and chlorides of

chlorides and simple hydrides of the elements these elements, and their behaviour with water. (Hydrides of boron are not Li to Cl

9.

Investigation of the properties of the oxides and chlorides of the period 3 elements.

required.)

The s- Block Elements

9.1 Characteristic properties of the s- block elements

Metallic character and low electronegativity. Formation of basic oxides and

Flame tests for Li+, Na+, K+, Ca2+, Sr2+ and Ba2+

hydroxides. Predominantly ionic bonding with fixed oxidation state in their

ions.

compounds. Characteristic flame colours of salts. Weak tendency to form complexes.

9.2 Variation in properties of the s- block

Variations in atomic radii, ionization enthalpies, melting points and hydration

Investigation of the effect of heat on carbonates

elements and their compounds

enthalpies. Interpretation of these variations in terms of structure and bonding.

of Group II elements.

Reactions of the elements with hydrogen, oxygen, chlorine and water.

Investigation of the solubility of sulphates(VI)

29

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Reactions of the oxides, hydrides and chlorides with water, acids and alkalis.

and hydroxides of Group II elements.

Relative thermal stability of the carbonates and hydroxides.

Relative solubility of the sulphates( VI) and hydroxides.

9.3 Uses of the compounds of the s- block

Sodium carbonate in the manufacture of glass.

elements

Sodium hydrogencarbonate in baking powder. Sodium hydroxide in making soap. Magnesium hydroxide as an antacid. Slaked lime in neutralization of acids in industrial effluents. Strontium compounds in fireworks.

10. The p- Block Elements

10.1 The halogens

Characteristic properties of the halogens

High electronegativity and electron affinity. Ionic and covalent bonding in oxidation state –1.

Variation in properties of the halogens and

Variations in melting and boiling points, electronegativities and electron

Investigation of the reactions of

their compounds

affinities. Interpretation of these variations in terms of structure and bonding.

a.

halogens with alkalis,

Relative oxidizing power of halogens: comparative study of reactions (Cl 2 ,

b.

halides ions in solution, and

Br 2 and I 2 ) with sodium, iron( II) ion and phosphorus.

c.

solid halides with sulphuric(VI) acids.

Disproportionation of the halogens in alkalis.

30

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

Comparative study of the reactions of halide ions with halogens, sulphuric( VI) acid, phosphoric( V) acid and silver ions. Acidic properties of hydrogen halides and the anomalous behaviour of hydrogen fluoride.

Uses of halogens and halogen containing

Fluoride in fluoridation of water. Chlorine in the manufacture of poly(

compounds

chloroethene), bleach and disinfectant. Silver bromide in photographic films.

Unreactive nature of nitrogen. Direct combination of nitrogen and oxygen 10.2 Nitrogen and its compounds

leading to formation of nitrogen oxides. Manufacture of ammonia by Haber process and its underlying physicochemical principles. Ammonia as a reducing agent and a base. Catalytic oxidation of ammonia in the manufacture of nitric( V) acid. Nitric( V) acid as an oxidizing agent, limited to the study of the reactions with copper, iron( II) ion and sulphur only.

Action of heat on nitrates( V). Brown ring test for nitrate( V) ions.

Investigation of the action of heat on

10.3 Sulphur and its compounds

Burning of sulphur. Oxidizing and reducing properties of sulphur dioxide as

nitrates(V). Brown ring test for nitrate(V) ions.

exemplified by the reactions with manganate( VII) ion, dichromate( VI) ion,

Investigation of the redox properties of sulphur

bromine and magnesium metal. Manufacture of sulphuric( VI) acid by contact

dioxide.

process and itsunderlying physicochemical principles. Sulphuric( VI) acid as an oxidizing agent and a dehydrating agent. Test for sulphate( VI) ions. Uses of sulphuric( VI) acid in the manufacture of

31

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

fertilizers, detergents, paints, pigments and dyestuffs. Investigation of the redox

Test for sulphate(VI) ions using acidified

properties of sulphur dioxide.

barium chloride solution.

11. The d- Block Elements Electronic configurations (linked with Section 2. 4). d- Block elements as metals. 11.1 General features of the d- block elements Comparison of ionization enthalpies, electronegativities, melting points, from Sc to Zn

hardness, densities and reactions with water between d- block and s- block metals. Interpretation of the characteristic properties, viz. variable oxidation states,

11.2 Characteristic properties of the d- block

complex formation, coloured ions, and catalytic properties in terms of electronic

elements and their compounds:

structures, successive ionization enthalpies, atomic and ionic radii.

Studies limited to common oxidation states of vanadium (+ 2, +3, +4, +5) and (a) Variable oxidation states

manganese (+ 2, +4, +7). Interconversions of oxidation states of each element.

Investigation of the redox reactions of vanadium or manganese compounds.

Studies limited to complexes of Fe( II), Fe( III), Co( II) and Cu( II) with the (b) Complex formation

following ligands: H 2 O, NH 3 ,Cl –and CN –.

Investigation of the relative stability of some

Nomenclature of these complexes. Displacement of ligands and relative stability

copper(II) complexes.

of complex ions. (Experimentation involving cyanide ions should not be attempted.) (Calculations involving stability constants are not required). Stereostructures of 4- and 6- coordinated complexes.(Optical isomerism of complexes

32

Setter: SK Chan

POCA Wong Siu Ching Sec. Sch.

is not required.)

Studies limited to the hydrated ions of Fe( II), Fe( III), Co( II) and Cu( II). (c) Coloured ions Exemplified by the use of Fe in Haber process, Fe 2+or Fe 3+in the reaction (d) Catalytic properties of transition metals

between peroxodisulphate( VI) and iodide ions, and MnO 2 in the decomposition

Investigation of the catalytic action of d-block

and their compounds

of hydrogen peroxide (linked with Section5.7).

ions on the reaction between peroxodisulphate(VI) and iodide ions.

33

Setter: SK Chan