26.4 Reactions of Phenols Reaction with sodium metal, Na Reagent : Sodium metal, Na Condition : Room temperature Product : Alkoxides and hydrogen gas Like alcohols, phenol will react with a reactive metal such as sodium to give sodium phenoxide and...
26.3 Introduction to Phenols What are phenols? Phenols are benzene compounds which have an -OH group attached directly to it In a phenol molecule, one of the lone pairs on the oxygen overlaps with the delocalised electron system to give a structure...
26.2 Reactions of Benzene and Alkylbenzene Reactivity of benzene Unlike alkenes, benzene is resistant to addition reactions. This is because it involves breaking the delocalised electron system and thus losing its stability Instead, benzene undergoes...
26.1 Introduction to Aromatic Compounds Aliphatic and aromatic compounds Aliphatic compounds are organic compounds that have carbon atoms joined together in straight chains, branched chains or non-aromatic rings. Aromatic compounds are organic compounds that...
25.3 Complex Ions Ligand and complex A ligand is a molecule or ion with a lone pair of electrons, capable of forming a co-ordinate bond to a metal atom or ion. Some examples of ligands are water, ammonia and chloride ion A complex is a molecule or ion...
CHAPTER 26: Benzene and Its Compounds Introduction to Aromatic Compounds Reactions of Benzene and Alkylbenzene Introduction to Phenols Reactions of Phenols Learning outcomes: describe the chemistry of arenes as exemplified by the following reactions of benzene and...
25.1 Introduction to Transition Elements Transition and d-block elements A transition element is one which forms one or more stable ions with incompletely filled orbitals A d-block element is one which has electrons filling the d-orbitals. From the above...
25.2 Oxidation States of Transition Elements Variable oxidation states One characteristic property of transition elements is that they have variable oxidation states. For example, iron can exist in 0, +2 or +3 oxidation state. This is because the 4s and 3d...
24.4 Relative Stability of +2 and +4 Oxidation States The stability of +2 and +4 oxidation states +4 compounds at the top of the Group is more stable than at the bottom. +2 compounds at the bottom of the Group is more stable than at the top. For carbon, carbon...
CHAPTER 25: Transition Elements Introduction to Transition Elements Oxidation States of Transition Elements Complex Ions Learning outcomes: explain what is meant by a transition element, in terms of d-block elements forming one or more stable ions with incomplete...
24.3 Group IV Oxides Introduction to Group IV oxides Group IV elements form two types of oxides: monoxide and dioxide. This is because the elements have two possible oxidation states, +2 and +4. Monoxides include: carbon monoxide, CO silicon...
24.2 Group IV Chlorides Introduction to Group IV chlorides All Group IV chlorides are simple covalent molecules which exist as liquid at room temperature with the general formula of XCl4, where X = A Group IV element. All of them have a tetrahedral shape...
24.1 Physical Properties of Group IV Elements Introduction to Group IV elements Group IV elements are p-block elements with a characteristic outer shell configuration of ns²np². Group IV elements exist in two different oxidation states, +2 and +4 states. The +2...
23.3 Catalysis Phase and physical state A phase is a region of space, throughout which all physical properties of a material are essentially uniform Examples of phases: Heterogeneous catalysis Heterogeneous catalysis involves the use of a catalyst which is...
CHAPTER 24: Group IV Physical Properties of Group IV Elements Group IV Chlorides Group IV Oxides Relative Stability of +2 and +4 Oxidation States Learning outcomes: outline the variation in melting point and in electrical conductivity of the elements...
23.2 Reaction Mechanisms Rate-determining step In any chemical change, some bonds are broken and new ones are made. Quite often, these changes are too complicated to happen in one simple stage. Instead, the reaction may involve a series of small changes one...
23.1 Orders of Reaction and Rate Equations Rate Equation The rate of reaction is dependent on the concentration of the reactants. Doubling the concentration may double or triple the rate of reaction, just to name a few A rate equation shows this...
22.4 Solubility Equilibria Solubility product, ftsp Solubility product, ftsp is the product of the concentrations of each ion in a saturated solution of a sparingly soluble salt at 298 K, raised to the power of their relative concentrations For any so called...
CHAPTER 23: Reaction Kinetics Orders of Reaction and Rate Equations Reaction Mechanisms Catalysis Learning outcomes: explain and use the terms: rate equation, order of reaction, rate constant, half-life of a reaction, rate-determining step construct and use...
22.3 Buffer Solutions What is a buffer solution? A buffer solution is a solution whose pH does not change significantly when small amount of acid or base is added to it Buffer solutions should therefore contain: large amount of acid to react with the...
22.1 Acid-base Titrations Titration curves Titration curves or pH curves are curves that show the pH changes during an acid-base titration. Titration curve of a strong acid and strong base titration, take hydrochloric acid and sodium hydroxide as an example:...
22.1 pH, fta, pfta and ftw The ionic product of water, ftw Water is able to act as an acid as well as a base. Therefore whenever liquid water is present, the following equilibrium occurs 2H2O ⇌ H3O⁺ + OH⁻ Or the more simplified version(Note that H⁺ ≡ H3O⁺): H2O ⇌ H⁺...
21.4 Quantitative Electrolysis E° value in electrolysis Recall that the selective discharge of ions during electrolysis is affected by: the position of ions in the electrochemical series the concentration of ions Cations lower in the electrochemical series will be...
CHAPTER 22: Ionic Equilibria pH, fta, pfta and ftw Acid-base Titrations Buffer Solutions Solubility Equilibria Learning outcomes: explain the terms pH, fta, pfta, ftw and use them in calculations calculate [H⁺(aq)] and pH values for strong and weak acids and...
21.4 Cells and Batteries Rechargable and non-rechargeable cells Batteries are electrochemical cells used as portable sources of electricity Primary cells cannot be recharged and are discarded once the supply of electric current decreases. This happens when the...
20.3 Using E° Values The usage of E° values The value of standard electrode potential, E° can be used in some ways: To predict standard cell potentials, E°cell. To determine the direction of electron flow To predict the feasibility of reactions To determine the...
21.2 Measuring Standard Electrode Potential The big picture The standard electrode potential of the following system will be considered: A metal/metal ion half-cell with SHE A non-metal/non-metal ion half-cell with SHE An ion/ion(with different oxidation states)...
21.1 Standard Electrode Potential Electrode potentials and half-cells When a metal, M is immersed into water, there is a tendency that it will lose electrons and enter the water as metal ions, Mª⁺. Soon, the water becomes a solution of the metal ions. This leaves...
CHAPTER 21: Electrode Potentials Standard Electrode Potential Measuring Standard Electrode Potential Using E° Values Cells and Batteries Quantitative Electrolysis define the terms: standard electrode (redox) potential standard cell potential describe the...
20.4 Enthalpy Changes in Solutions Recall enthalpy change of solution and hydration Standard enthalpy change of solution, ΔH°sol is the enthalpy change when one mole of ionic compounds is dissolved in water to form an infinitely dilute solution under standard...
20.3 Ion Polarisation Polarising power and polarisability Not all ionic compounds are fully ionic, the same goes to covalent compounds. Pure ionic and covalent bondings are extremes In an ionic compound, the positive charge on the cation may attract the...
20.1 Born-Haber Cycles What are Born-Haber cycles? Lattice energy cannot be determined experimentally, however, it can be calculated using a special type of Hess' cycle, this is called the Born-Haber cycle. It assumes that the final product is the solid...
19.3 Esters Introduction to esters Esters are derivatives of carboxylic In an ester, the hydrogen from the -COOH group of carboxylic acid is replaced by an alkyl group. The alkyl group came from the alcohol/phenol. Some common esters and their naming: Note that the...
CHAPTER 20: Lattice Energy Introduction to Lattice Energy Born-Haber Cycles Ion Polarisation Enthalpy Changes in Solutions Learning outcomes: explain and use the term lattice energy (∆H negative, e. gaseous ions to solid lattice). explain, in qualitative terms, the...
20.1 Introduction to Lattice Energy What is lattice energy? In a solid ionic crystal lattice, the ions are bonded by strong ionic bonds between them. These forces are only completely broken when the ions are in gaseous state Lattice energy(or lattice...
19.2 Reactions of Carboxylic Acids Acidity of carboxylic acids Carboxylic acids are acidic because they can donate a proton to form carboxylate ion and hydroxonium The presence of hydroxonium ions makes the solution acidic. RCOOH + H2O ⇌ RCOO⁻ + H3O⁺ However,...
19.1 Carboxylic Acids Introduction to carboxylic acids Carboxylic acids are compounds that contain the -COOH group. Examples of carboxylic acids: Salts of carboxylic acids are called carboxylate salts. The formation of carboxylate salts shows that carboxylic acids...
18.3 Tests for Aldehydes and Ketones Test for carbonyl group using 2,4-dinitrophenylhydrazine(2,4-DNPH) 2,4-dinitrophenylhydrazine or 2,4-DNPH can be used to detect the presence of carbonyl group, C=O. The structure of 2,4-DNPH is shown below: This test is usually...
CHAPTER 19: Carboxylic Acids and Derivatives I Carboxylic Acids Reactions of Carboxylic Acids Esters Learning outcomes: describe the formation of carboxylic acids from alcohols, aldehydes and nitriles describe the reactions of carboxylic acids in the formation of:...
18.2 Reactions of Aldehydes and Ketones Reactivity of carbonyl compounds The C=O bond of the carbonyl group is highly polarised due to oxygen atom being more electronegative This causes the slightly positive carbon atom to be susceptible to nucleophilic...
18.1 Introduction to Aldehydes and Ketones What are carbonyl compounds? 1) Carbonyl compounds are compounds that contain the C=O(carbonyl) group. Examples are aldehydes and ketones. Physical properties of carbonyl compounds The boiling point of...
17.2 Reactions of Alcohols Summary Summary of reactions that alcohols undergo: Combustion Dehydration to give alkenes Reaction with sodium Substitution to give halogenoalkanes Oxidation Esterification Combustion Reagent : Oxygen supply Condition : Heat...
CHAPTER 18: Carbonyl Compounds Introduction to Aldehydes and Ketones Reactions Aldehydes and Ketones Tests for Aldehydes and Ketones Learning outcomes: describe: the formation of aldehydes and ketones from primary and secondary alcohols respectively using Cr2O7²⁻/H⁺....
17.1 Introduction to Alcohols What are alcohols? Alcohols are compounds in which one or more hydrogen atoms in an alkane have been replaced by an -OH group Alcohols can be classified as primary, secondary or tertiary depending on the number of alkyl groups(R...
CHAPTER 17: Hydroxy Compounds Introduction to Alcohols Reactions of Alcohols Learning outcomes: recall the chemistry of alcohols, exemplified by ethanol: combustion substitution to give halogenoalkanes reaction with sodium oxidation to carbonyl compounds and...
16.3 Uses of Halogenoalkanes The use of CFCs CFCs are chlorofluorocarbons, compounds containing carbon with chlorine and fluorine atoms attached. Two common CFCs are CFC-11(CCl3F) and CFC-12(CCl2F2). Some properties and uses of CFCs: CFCs and the environment...
16.2 Reactions of Halogenoalkanes Chemical reactivity of halgenoalkanes Fluoroalkanes are the least reactive while iodoalkanes are the most reactive. This is because the carbon-halogen bond strength decreases from fluorine to iodine as the size of the halogen...
16.1 Introduction to Halogenoalkaes What are halogenoalkanes? Halogenoalkanes(or alkyl halides) are compounds in which one or more hydrogen atoms in an alkane have been replaced by halogen atoms (fluorine, chlorine, bromine or iodine). Halogenoalkanes can be...
15.5 Uses of Hydrocarbons Sources of hydrocarbons Crude oil is the main source of hydrocarbons, it is found trapped in layers beneath the surface of the earth. Crude oil is a complex mixture of hydrocarbons - alkanes, cycloalkanes and aromatic compounds. [ Note:...
CHAPTER 16: Halogen Derivatives Introduction to Halogenoalkanes Reactions of Halogenoalkanes Uses of Halogenoalkanes Learning outcomes: recall the chemistry of halogenoalkanes as exemplified by the following nucleophilic substitution reactions of bromoethane:...
15.4 Reactions of Alkenes Electrophilic addition Unlike alkanes, alkenes are more reactive because they are unsaturated and contain a C=C bond. A C=C bond contains a σ bond and a π A π bond is a region of high density of electron which is open to attack...
15.3 Introduction to Alkenes What is an alkene? Alkenes are unsaturated hydrocarbons which contain at least one carbon-carbon double bond(C=C) bond. They form the homologous series with the general formula of CnH2n. The physical properties of alkenes are similar to...
15.2 Reactions of Alkanes Reactivity of alkanes Alkanes are saturated and generally unreactive because they are non-polar, hence they are unattractive towards nucleophiles and electrophiles Alkanes will only react with non-polar reagents in the presence of heat or...
15.1 Introduction to Alkanes What is an alkane? A hydrocarbon is a compound containing carbon and hydrogen atoms Examples of hydrocarbons are alkanes, alkenes, alkynes and arenes. Alkanes are saturated hydrocarbons, the carbon atoms are joined to each...
14.3 Isomerism What are isomers? Isomers are two or more compounds with the same molecular formula but a different arrangement of atoms in space. Organic molecules which exhibit this property show isomerism This excludes any different arrangements which are simply due...
CHAPTER 15: Hydrocarbons Introduction to Alkanes Reactions of Alkanes Introduction to Alkenes Reactions of Alkenes Uses of Hydrocarbons Learning outcomes: show awareness of the general unreactivity of alkanes, including towards polar reagents describe the...
14.2 Organic Reactions Reactions that organic compounds undergo Organic reactions are classified using two ways: By the type of reagent used: Nucleophilic Electrophilic By what happens during the reaction: Addition Substitution Elimination Some common reactions:...
14.1 Organic Compounds What is organic chemistry? 1) Organic chemistry is the study of carbon compounds (excluding simple compounds like CO, CO2, CO3²⁻, HCO3⁻). Formulae of organic compounds There are five ways in which organic compounds/molecules can be...
13.2 Environmental Consequence of Using Nitrogen Compounds Excessive use of nitrate fertilisers When excessive nitrate or ammonium fertilisers are used, the unabsorbed ones will dissolve in rain water and it leaches into lakes and rivers An excess of these...
13.3 Sulfur Compounds Uses and formation of sulfur dioxide, SO2 and its consequences Atmospheric sulfur dioxide is formed during the burning of fossil fuels. Fossil fuels like coal and oil all contain sulfur compounds, and when the coal or the oil product are...
CHAPTER 14: An Introduction to Organic Chemistry Organic Compounds Organic Reactions Isomerism Learning outcomes: interpret, and use the general, structural, displayed and skeletal formulae of the following classes of compound: alkanes and alkenes...
13.1 Nitrogen Compounds The lack of reactivity of nitrogen Nitrogen, N2 exists as a diatomic molecule, two nitrogen atoms are bonded by a triple bond Nitrogen is very unreactive because the bond energy is very high (about +944 kJ mol⁻¹) and reactions involving...
12.3 Reactions of Halide Ions Introduction to halide ions, X⁻ The halogens are typical non-metals, they: form singly charge negative ions, X⁻. form ionic compounds with metals and covalent compounds with non-metals. Preparation of halogens in the...
12.4 Uses of Halogens Chlorine is used in the chlorination of water to kill bacteria. The chlorine undergoes disproportionation Cl2(aq) + H2O(l) → HCl(aq) + HClO(aq) Chloric(I) acid, HClO produced decomposes slowly to produce reactive oxygen atoms that kill...
CHAPTER 13: Nitrogen and Sulfur Nitrogen Compounds Environmental Consequences of Using Nitrogen Compounds Sulfur Compounds Learning outcomes: explain the lack of reactivity of nitrogen describe and explain: the basicity of ammonia the structure of the ammonium...
12.12Reactions of Group VII Elements Halogens as oxidising agent Halogens are powerful oxidising agents. However, the oxidising ability decreases down the Therefore, F2 is the most powerful oxidising agent while I2 is the weakest. This is reflected in their ability...
12.1 Physical Properties of Group VII Elements Introduction to Group VII elements Group VII elements(also called the 'halogens') are p-block elements with a characteristic outer shell configuration of ns²np⁵. Some common physical properties of the halogens...
11.3 Group II Oxides, Hydroxides and Carbonates Group II oxides All Group II oxides(except beryllium oxide) reacts with water, at least to some extent to give the corresponding hydroxides Beryllium oxide is insoluble because Be²⁺ ion is a very small and highly charged...
11.4 Thermal Decomposition Thermal decomposition of Group II salts In general, compounds with high charge density cation and large anion size tend to decompose more easily(less stable on heat) due to the greater polarisation of anion by the cation. Thermal...
11.5 Uses of Group II Compounds 11.1 of Group II Compounds Some ceramics contain magnesium oxide, MgO and they can be used as: electrical insulators in industrial electrical cables a refractory in furnace linings because it has a high melting (However, it...
CHAPTER 12: Group VII Physical Properties of Group VII Elements Reactions of Group VII Elements Reactions of Halide Ions Uses of Halogens Learning outcomes: describe the colours of, and the trend in volatility of chlorine, bromine and iodine interpret the...
11.2 Reactions of Group II Elements Reaction with oxygen gas, O2 All Group II elements(except beryllium) burn in oxygen with a bright flame to form monoxides 2M(s) + O2(g) → 2MO(s) ; where M = A Group II element 2Mg(s) + O2(g) → 2MgO(s) ; burns with brilliant...
11.1 Physical Properties of Group II Elements Introduction to Group II elements Group II elements(also called the 'alkaline earth metals') are s-block elements with a characteristic outer shell configuration ns². Group II elements are very reactive metals. They...
10.3 Period 3 Oxides Summary of the properties of Period 3 oxides. Reaction with water, H2O Sodium oxide reacts exothermically with cold water to form sodium A strongly alkaline solution of sodium hydroxide is produced. Na2O(s) + H2O(l) → 2NaOH(aq) ; pH = 13...
10.4 Period 3 Chlorides Summary of the properties of Period 3 chlorides Reaction with water, H2O Sodium chloride dissolves in water to form a neutral solution of sodium chloride. NaCl(s) + aq → Na⁺(aq) + Cl⁻(aq) ; pH = 7 Magnesium chloride dissolves in water...
CHAPTER 11: Group II Physical Properties of Group II Elements Reactions of Group II Elements Group II Oxides, Hydroxides and Carbonates Thermal Decomposition Uses of Group II Compounds Learning outcomes: describe the reactions of the elements with oxygen, water and...
10.2 Periodicity in Chemical Properties Reaction with oxygen gas, O2 Sodium burns on heating with an orange-yellow flame to form white sodium oxide 4Na(s) + O2(g) → 2Na2O(s) Magnesium burns on heating with a brilliant white flame to form white...
10.1 Periodicity in Physical Properties What is periodicity? 1) Periodicity is the recurrence of similar properties at regular intervals when the elements are arranged in increasing atomic number. Variation in size of atoms Covalent radius is half the...
9.2 Catalysis What is a catalyst? A catalyst is a substance that increases the rate of reaction but is chemically unchanged at the end of the reaction Catalysis is the increase in the rate of chemical reaction by a catalyst Characteristics of catalysts: Catalysts...
CHAPTER 10: Chemical Periodicity Periodicity in Physical Properties Periodicity in Chemical Properties Period 3 Oxides Period 3 Chlorides Learning outcomes: describe qualitatively (and indicate the periodicity in) the variations in atomic radius, ionic radius,...
9.1 Factors Affecting the Rate of Reaction How to increase the rate of reaction? According to the collision theory, the rate of reaction will increase if: the frequency of collision and effective collision increases the proportion of particles with energy greater...
9.1 Rate of Reaction What is the rate of reaction? Rate of reaction is the change in concentration of reactants or products per unit time. It refers to the rate of product formed or the rate of reactant used up A balanced chemical equation gives no information...
8.4 Theory of Acids and Bases The Arrhenius theory According to Arrhenius theory: An acid is a substance which ionises in water to give hydrogen ions, H⁺. A base is a substance which ionises in water to give hydroxide ions, OH⁻. Limitations of this theory: When...
CHAPTER 9: Rate of Reaction Rate of Reaction Factors Affecting Rate of Reaction Catalysis Learning outcomes: explain and use the terms: rate of reaction, activation energy and catalysis explain qualitatively, in terms of collisions, the effect of concentration...
8.3 Equilibrium Constants Equilibrium constants, ftc and ftp Equilibrium constant is the value of the reaction quotient when the reaction has reached equilibrium. Alternatively, it can also be defined as the measure of the extent in which reactants are converted...
8.1 Dynamic Equilibria Reversible reactions A reversible reaction is one which can proceed in both directions, as indicated by the "⇌" sign. For example: H2 + I2 ⇌ 2HI 2SO2 + O2 ⇌ 2SO3 In a reversible reaction, the reactants react to form the...
8.2 Factors Affecting Chemical Equilibria Position of equilirbium 1) The position of equilibrium refers to the relative amount of products and reactants present in an equilibrium mixture. Le Chatelier's principle Le Chatelier's principle states that if a...
7.2 Electrolysis Electrolytic cells Electrolysis is the decomposition of a compound into its elements by an electric current. Uses of electrolysis: to extract useful metals from their ores to produce useful by-products such as chlorine gas to purify metals...
CHAPTER 8: Chemical Equilibria Dynamic Equilibria Factors Affecting Chemical Equilibria Equilibrium Constant Theory of Acids and Bases Learning outcomes: explain, in terms of rates of the forward and reverse reactions, what is meant by a reversible...
7.1 Oxidation and Reduction Redox reactions Oxidation is: gain of oxygen loss of hydrogen loss of electrons increase in oxidation number Reduction is: gain of hydrogen loss of oxygen gain of electrons decrease in oxidation number Oxidation and...
CHAPTER 7: Redox Reactions and Electrolysis Oxidation and Reduction Electrolysis Learning outcomes: calculate oxidation numbers of elements in compounds and ions describe and explain redox processes in terms of electron transfer and/or changes in oxidation number...
6.4 Bond Energy Bond breaking and bond forming Breaking bonds needs energy, energy is absorbed from the Therefore, bond breaking is an endothermic process. Forming bonds releases energy to the surroundings. Therefore, bond forming is an exothermic process. If the...
6.3 Hess' Law Hess' law and Hess' cycle Hess' law states that the total enthalpy change in a chemical reaction is independent of the route which the reaction takes place as long as the initial and final conditions are the same For example, the enthalpy change of...
6.1 Enthalpy Changes Exothermic and endothermic reactions Most chemical reactions are accompanied by energy changes. Some absorbs energy while some releases it An exothermic reaction is a reaction that releases energy to the surroundings. Therefore the product...
6.2 Standard Enthalpy Changes The standard condition To make comparison of enthalpy changes a fair comparison, same conditions must be used. These are called the standard conditions: A pressure of 100 kPa(approximately atmospheric pressure). A temperature of 298 K...
5.3 The Solid State Kinetic theory of solids In solids, very strong forces of attraction hold the particles in ftxed positions and close to each other. Hence, particles in the solid state can only rotate and cannot translate A solid has ftxed shape and volume. The...
5.4 Ceramics Ceramics A ceramic is an inorganic non-metallic solid which is prepared by heating a substance or mixture of substances to a high temperature Ceramics often contain silicon dioxide, magnesium oxide and aluminium This gives ceramics their giant covalent...
5.5 Conserving Materials Why conserve materials? 1) There is only a limited supply of metal ores in the Earth. Therefore metals are ftnite resources. They do not get replaced once they are used up. Ways to conserve materials One way to conserve materials is...
CHAPTER 6: Chemical Energetics Enthalpy Changes Standard Enthalpy Changes Hess' Law Bond Energy Learning outcomes: explain that some chemical reactions are accompanied by energy changes, principally in the form of heat energy; the energy changes can be...
5.2 The Liquid State Kinetic theory of liquids In liquids, the particles are packed quite closely together but in a fairly random arrangement(gaps are present between them). So, the particles have limited movements. A liquid has ftxed volume but do not have...