Chemistry Chapter Summaries

8/8/2019 Chemistry Chapter Summaries

1/23

5

Light is a form of electromagnetic radiation. It wavelength, frequency and

velocity are related by the formula c=v

The electrons in an atom can exist in only certain allowed energy levels

The line spectra o atoms indicate that electrons can transfer from one energy

level to another by the absorption or emission of photons which contain definite

amounts or quanta of energy

An electron in an atom exists in a definite energy level but does not have a

definite location. The region in which an electron moves for most of its time is

called an orbital. Each orbital can hold a maximum of two electrons

The relationship between principle energy level, energy sublevel and orbitals:

Principleenergylevel (n)

Numberof energysublevels(n)

Energysublevels

Numberoforbitalswithineachenergysublevel

Maxelectronpopulation ofenergysublevel

Totnumberoforbitals inprincipleenergylevel (n)

Maxelectronsinprincipleenergylevel(2n)

1 1 s 1 2 1 22 2 s 1 2 4 8

p 3 63 3 s 1 2 9 18

p 3 6d 5 10

4 4 s 1 2 16 32p 3 6d 5 10f 7 14

The arrangement of elements in the periodic table is related to their electron

configurations as follows

Groups I and II (s block) - filling s sublevel

Groups III to VIII (p block) filling p sublevel

Transition elements (d block) filling d sublevel

Lanthanides and actinides (f block) filling f sublevel

The electron configuration of atoms can be represented in several ways, shown

for sodium as follows

2, 8, 1

1s 2s2p6 3s1

Showing electrons in orbitals


2/23

Elements with the same electron configuration in their outer principle energy

level have similar properties

The ionisation energy is the amount of energy required to remove the most

loosely bound electron from a gaseous atom

The first ionisation energy:

1. Increases across a period

2. Decreases down a group

Successive ionisation energies increase for an atom

1. Gradually as the charge on the ion formed increases

2. Markedly when the electron is removed from a lower principle energy level

The valence electrons of an atom are the electrons in the outer principle energy

level

6

Substances are classified into four classes based on their properties

Class Property Melting Point ConductivitySolid Melt

Metallic Variable hardness,malleable

High High High

Ionic Very hard, verybrittle

High None High

CovalentMolecular

Soft brittle solids,can be solids,liquids or gases atroom temperature

Low None None

Covalent Network Very hard, brittle Very high None None

A metal consists of a lattice of positive metallic ions surrounded by a sea of

mobile delocalised valence electrons

Metallic bonding is the electrostatic attraction between the delocalised electrons

and the positive metallic ions

The metallic bonding model can be used to explain the properties of metals

Property ExplanationRelatively high density Ions tightly packed in the latticeMalleable and ductile Metallic bonding is non-directional,

therefore metal lattices can bedeformed without disrupting the

metallic bondingConductivity of electricity and heat Mobile delocalised electrons transfer


3/23

charge and heat energyHigh MP and BP Strong metallic bonding exists

throughout the entire lattice

Ionic substances consist of positive ions and negative ions arranged in a regular

lattice

Ionic bonding is the electrostatic attraction between oppositely charged ions

The ionic bonding model can be used to explain the properties of ionic crystals

Property ExplanationHard and brittle Ions are tightly bound by electrostatic

forces in the crystal lattice. A stressleading tending to distort the crystalcauses repulsion between similarlycharged ions

Non conductivity of electricity whensolid

Ions occupy fixed positions in thelattice

Conductivity of electricity when moltenor in aqueous solution

Mobile ions can transfer electric charge

High MP and BP Ions tightly bound by strongelectrostatic forces

Sodium chloride or common salt is an important ionic compound. Adults need

about 2g of sodium (as Na+) or about 5g of NaCl each day

The noble gas valence electron configuration of eight electrons, called an octet,

is very stable

Ions are formed by the transfer of electrons from an atom of an element of low

ionisation energy to an atom of an element of high ionisation energy

When elements form an ionic compound they achieve a stable octet by gaining

or losing electrons

Electron dot diagrams can be used to show the arrangement of valence electrons

in atoms, molecules and ion

7

Covalent molecular substances include most non-metal elements and most

compound consisting of non-metals only

Within molecules, atoms are held together by the electrostatic attraction

between shared electrons and the nuclei of adjacent atoms. This form of bonding

is called covalent bonding

A single covalent bond is formed when two atoms share a pair of valence energy

level electrons which allows each atom to acquire a noble gas electron

configuration


4/23

A double covalent bond two atoms share two pairs

A coordinate covalent bond is a covalent bond in which one atom provides both

electrons of the shared pair

When atoms combine to form molecules they tend to share electrons so thattheir outer energy level has eight electrons or a noble gas configuration. This is

known as the octet rule. There are exceptions to this rule, especially with

elements which have a higher electron capacity than eight in their valence

energy level (PCl5, SF6, BF3, BeF2, NO, NO2) PNOS B Be

Some compounds contain both ionic and covalent bonds

The shapes of molecules depend on the arrangement in space of the bonding

and non-bonding valence electron pairs of the central atom. The electron pairs

are arranged as far apart as possible to minimise repulsion

Number ofvalence electronpairs

Number ofbonding pairs

Geometry ofmolecule

1 1 Linear2 2 Linear3 3 Triangular planar4 4 Tetrahedral4 3 Pyramidal4 2 Bent4 1 Linear

Electronegativity is a measure of the tendency of an atom to attract electrons

A polar covalent bond is one which there is an uneven charge distribution

between atoms due to unequal attraction of the shared electrons

A polar molecule is one in which there is an uneven charge distribution. The

situation in which there is a separation of positive and negative charge is called

a dipole

To be polar, a molecule must contain one or more polar covalent bonds, and not

be totally symmetrical

When a molecule contains more than one polar bond, the polarity of the

molecule is found by adding vectorially the strength of each of the dipoles

There are three types of attractive forces between molecules which are

collectively known as van der Waals forces

o Dipole-dipole, Dispersion, Hydrogen bonds

Dipole-dipole forces are the forces of attraction between polar molecules

Dispersion forces ate tweak attractive forces existing between all molecules.They arise from the interaction between a temporary dipole and the dipole it


5/23

induces in a neighbouring molecule. In non-polar substances, dispersion forces

are the only intermolecular interactions. The forces are weak but increase with

the number of electrons in a molecule

Hydrogen bonds are bonds between a hydrogen atom attached to an F, N or O

atom in one polar molecule and a non-bonding electron pair on an F, n or O atomin another polar molecule. Hydrogen bonds are stronger than normal dipole-

dipole forces

The properties of covalent molecular substances are:

Property ExplanationLow MP and BP Forces between molecules are weakNon conductors The molecules are uncharged and

electrons are localised in covalentbonds or on the atoms

Generally soft solids Forces between molecules are weak Covalent network substances include non-metal elements such as carbon and

silicon and some non-metal compounds such as silicon carbide and silicon

dioxide

In covalent network substances, every atom is covalently bonded to other atoms

forming a giant network. No separate molecules can be distinguished

The properties of covalent network:

Property Explanation

Very high MP and BP Strong covalent bonding extendingthroughout the lattice

Non-conductors (usually) Electrons localised in covalent bonds oron the atom

Hard and brittle Atoms strongly bound, distortionbreaks covalent bonds

Chemically inert The bonding extends throughout thecrystal and the non-polar nature of thebonding makes them resistant tochemical attack

Insoluble in water and most othersolvents

The strong covalent bonding extendingthroughout the crystal lattice accountsfor the insolubility of these substances

Carbon exists in three allotropic forms-diamond, graphite and buckyballs

8

Mendeleev identified the periodic variation in the properties of the elements

when they are arranged in order of increasing atomic mass

In the modern form of the periodic table, the elements are listed in order of

atomic number and the periodic law states that the properties of the elementsare a periodic function of atomic number


6/23

The trends in the properties:

o Across a period: atomic radius decreases, IE increases, EN increases, non-

metallic character increases

o

Down a group: atomic radius increases, IE decreases, EN decreases,metallic character increases

In general, there is a great variation in properties across a period, whereas in a

group element exhibit more similarities in properties

The group I or alkali metals are very reactive and tend to form +1 ions in the

reactions

o Oxide to form a metal oxide

o

Chlorine to form a metal chloride

o Water to produce hydrogen gas

o Acids explosively to form hydrogen gas

Hydrogen is prepared in the lab by the reaction of a metal with dilute acids

o E.g. Zn + 2HCl ZnCl2 + H2

Hydrogen tends to form covalent molecular compounds when it reacts with other

non-metal elements. It reacts explosively with oxygen to form water. This

reaction is known as the pop test. 2H2 + O2 2H2O

The group II or alkaline earth metals are reactive and tend to form 2+ ions in

their reactions, They undergo similar reactions to the group I elements abut are

generally not as reactive

The group VII elements or halogens are very reactive non-metal which exist as

diatomic molecules. They tend to form -1 ions in their reactions with metals and

covalent molecules in their reactions with non-metals

The group VIII elements or noble gases exist as simple atoms. They are inert

because they have a complete octet in the outer energy level

The elements in which the d energy sublevels are being filled are called the

transition elements

The transition metals are widely used in society because of their useful

properties and relative abundance

o All metals (malleable and ductile, good conductors)

o They have fairly high densities

o They have fairly high MP and BP


7/23

o They are not as reactive as group I and II metals

o They exist in a variety of ionic states

o They commonly form coloured compounds

o They form coordination complexes in with surrounding ligands form

coordinate covalent bond with the central metal ion

The coordination number of a complex ion is the number of coordinate covalent

bonds formed between the central metal ion and surrounding ligands

11

A solution is a homogenous mixture

Different types of solutions occur such as gas in gas, solid in liquid or gas in

liquid, and solid in solid

Solutions are classified:

Saturated Unsaturated SupersaturatedContains as much soluteas the amount of solventcan dissolve at a specifictemperature

Contains less solute thanis needed to saturate it

Contains more solutethan is needed tosaturate it

The solubility of a solute depends on the nature of the solute and solvent. Polarsolvents tend to dissolve polar solutes. Non-polar solvents tend to dissolve

non=polar solutes

Water tends to dissolve polar solutes and many ionic compounds

In aqueous solutions ions are surrounded by polar water molecules

The solubility of solids in liquids usually increases with temperature

The solubility of gases in liquids usually decrease with temperature

The solubility of a gas in a liquid increases with the partial pressure of the gas

above the liquid

An electrolyte is a substance which when dissolved in water produces a

conducting solution

Dissociation is the process by which an ionic crystal separates into ions when it

dissolves

Ionisation occurs when a covalent molecular substance dissolves to form ions

which separate in solution


8/23

Substances are classified as strong, weak or non-electrolytes

o Strong: substances which are essentially completely ionised in solution

o Weak: substances in which only a small fraction of the dissolved molecules

are ionised in solution

o Substances which do not produce ions when dissolve in solution

The conductivity of a solution depends on the strength of the electrolyte, the

solubility of the electrolyte and the concentration of the electrolyte solution

Natural aquatic systems contain dissolved O2, CO2, nitrogen (as NO3- and NH4

+)

and phosphorous (as H2PO4-) which support aquatic life

Environmental problems in aquatic systems include algal blooms, resulting from

high nutrient levels, and salination of soils and waterways

Sea water in a 3.5% solution of ionic compounds and is an important source of

salt for any other substances

Drinking water has added to it chlorine to destroy harmful bacteria and fluoride

to reduce dental decay

Caves are formed when water containing carbon dioxide dissolves limestone

Cave formations develop when a saturated solution of calcium or magnesium

hydrogencarbonate evaporates

Hard water is water which contains high concentrations of salts, particularly the

calcium and magnesium salts of hydrogencarbonate, chloride and sulphate ions

Soaps do not function effectively in hard water as the stearate ion precipitates

out with the Ca and Mg ions. Detergents function in all types of water

Hardness can be removed by:

o Boiling to remove temporary

o Treatment with washing soda (Na2CO3.10H2O)

o Treatment with complex water softeners

o Deionisation with ion exchange resins

o Distillation

Concentrations can be expressed as gL-1, % composition, ppm and mol L-1

The number of moles of solute in a solution is given by the formula n=cV


9/23

When a solution is diluted, the number of moles of the solute remains unchanged

but the concentration decreases

Different calculations involving chemical equations are possible (n=m/M, n=cV,

n=V/22.41)

Precipitation reactions occur when two solutions are mixed and an insoluble solid

is formed

Ionic equations are used for solution reactions to indicate more accurately the

reaction taking place. Spectator ions are not included.

Gravimetric analysis involves using the mass of a precipitate formed in a

precipitation reaction to determine the composition of a substance

Solutions of non-volatile solutes have lower vapour pressures, lower freezing

points and higher boiling points than the pure solvent. The changes in theseproperties depend on the concentration of solute particles in the solution

13

The rate of a chemical reaction is the speed with which reactants are converted

to products

Chemical rations display a great range of reaction rates from very fats, occurring

in a fraction of a second, to very slow, taking place over months or years

The rate of a chemical reaction can be expressed in terms of the rate of removal

of reactants or the appearance of product

Factors which effect the rate of reaction are the nature of the reactants,

concentration or pressure of the reactants, state of sub-division of the reactants,

temperature of the system and the presence of a catalyst

The collision theory of reaction rates is based on the idea that if particle are to

react they must first undergo a collision, For it to be successful and bring about a

change from reactants to products it must have sufficient energy to disrupt thebonds in the reactant molecules, and an orientation that is suitable for the

breaking of some bonds and the formation of others

Activation energy is the minimum energy that must be supplied by the reactant

particles in a chemical reaction if they are to react to form products

An energy profile diagram represents the energy changed which occurs in a

chemical reaction

The transition state or activated complex id the highest energy state in a

chemical reaction. The difference in energy between the reactants and thetransition state is the activation energy for the reaction


10/23

A successful collision is a collision between reactant particles which leads to the

formation of products

A reversible reaction is one in which the formation of products from reactants

and the formation of reactants from products are both significant. A reversible

reaction is represented by double arrows in the chemical equation

The nature of the reactants affects the rate of reactions because different

reactions have different activation energies. Reactions which involve the

breaking of many bonds tend to have higher activation energies and

consequently slower rates

Increasing the concentrations or gas pressures of reactants increases the rate of

collisions and hence the rate of reaction

Increasing the state of subdivisions of solids and liquids in heterogeneous

systems increases the rate of collisions between reactants and hence the rate of

reaction

Increasing the temperature increases the fraction of molecular collisions with

sufficient energy to overcome the activation energy barrier. This leads to an

increased rate of reaction

A catalyst increases the rate by providing an alternative reaction pathway with a

lower activation energy

Catalysts have important roles in the following

o Industrial manufacture of many chemical substances

o The removal of pollutants from combustion processes

o Life sustaining process in plants and animals

14

Chemical equilibrium in a closed system at a constant temperature ischaracterised by the following:

o Constant macroscopic properties, including constant concentrations of

reactants and products

o Equal reaction rates for the forward and reverse reactions

Chemical equilibrium is a dynamic process

Equilibrium exists in physical systems, including the following

o Equilibrium between liquid and vapour in a closed system


11/23


12/23

o Turn litmus red

o Conduct electric current

o Taste sour

o React with reactive metals to produce hydrogen gas

o React with (hydrogen)carbonates to form carbon dioxide

o React with metal (hydr)oxides to form a salt and water

Properties of aqueous solutions of bases:

o Turn litmus blue

o Conduct electric current

o Taste bitter

o React with amphoteric metals to produce hydrogen gas

o React with acids to form salt and water

o Dissolve amphoteric metal hydroxides

Arrhenius theory of acids and bases

o Acid is a substance with produces H+ ions in solution

o Base is a substance which produces OH- ions in solution

Bronsted-Lowry theory of acids and bases

o Acid is a proton donor

o Base is a proton acceptor

o Some substances can react as acids or bases in different reactions

o

Every acid has a conjugate base which is related in the difference of oneproton

o The stronger the acid, the weaker its conjugate base

o Acid-base reactions tend to occur in the direction in which a stronger acid

and stronger base react to form a weaker acid and weaker base

Water is a weak electrolyte which ionises to form H+ and OH- to a small extent

The relationship between the concentrations of H+ and OH- in any aqueous

solution at 25is given by the following: Kw= [H

+

][OH-

] = 1.0

10-14


13/23

The pH of any solution is calculated from: pH= -log10[H+]

The relationship between pH and acidity is 7=neutral, 7 basic

Strong acids and strong bases are essentially completely ionised or dissociated

into ions in aqueous solution

Weak acids and weak bases are those in which only a small proportion of the

molecules are ionised in aqueous solution

Polyprotic acids are those which contain more than one acidic or ionisable

hydrogen per formula unit of the acid

For polyprotic acids successive ionisations occur to successively smaller extents

Some bases contain more than one hydroxide ion per formula unit of the base

A neutralisation reaction is that between an acid and a base

Salts are ionic compounds containing a cation other than H+ and an anion other

than O2- or OH-

Nearly all salts are strong electrolytes

Salt solutions can be acidic, basic or neutral depending on the tendencies of the

ions in the salt to undergo hydrolysis

Carbon dioxide is slightly soluble in water and dissolves to form carbonic acid,

H2CO3. This is a weak diprotic acid which undergoes successive ionisation

reactions to form HCO3- and CO3

2-

Oxides and hydroxides decrease in acidity down groups in the periodic table

16

In volumetric analysis the amount of a particular substance in a sample is

determines by the measurement of the volume of a solution of known

concentration needed to react completely with the substance

A titration is the process in which a solution is added from a burette to another

solution with which it reacts, so that the volume of added solution can be

accurately measured

A volumetric flask is a flask which holds an accurately known volume of solution

A burette is used to deliver an variable but accurately known volume of solution

A primary standard is a substance which has the characteristics:

o Can be obtained in a very pure form


14/23

o Has a known formula

o An be accurately weighed

A standard solution is one whose concentration is accurately known

Standard solutions can be obtained by the following means

o Dissolving known mass of a primary standard to form a definite volume of

solution

o Standardising the solution by titration against a primary standard or a

previously standardised solution

An indicator is a substance which changes colour over a specific pH range

In an acid-base titration:

o The equivalence point is the point at which chemically equivalent amounts

of acid and base have been added. This is when the ratio of moles of acid

and base that have been added is the name as the ole ratio in the

balanced equation

o The end point is the point at which the added indicator changes colour

The pH at the equivalence point in various acid-base titrations:

Type of titration pH at equivalence point Indicator

SA and SB 7 Bromothymol blue,methyl orange,phenolphthalein

SA and WB 5 Methyl orangeWA and SB 9 Phenolphthalein

The preparations, properties and uses of hydrogen chloride, hydrochloric acid,

sulphur dioxide sulphuric acid, and nitric acid are important to note

The important properties of hydrochloric, sulphuric and nitric acids are as follows

o They all strong acids

o They neutralise bases

o Hydrochloric and sulphuric acids produce hydrogen gas with reactive

metals but nitric acid tend s to form nitric oxide

The preparations, properties and uses of sodium hydroxide, sodium carbonate

and ammonia should be known

Sodium hydroxide is a strong base but sodium carbonate and ammonia are

weak. All three neutralise acids


15/23

Sodium hydroxide will dissolve amphoteric metal hydroxides and react with

amphoteric metal to produce hydrogen

Ammonia solution will dissolve metal hydroxides which form complex ions

between the metal ions and ammonia molecules

Fertilisers are added to soils to provide the essential elements needed for plant

growth, including nitrogen, phosphorus, potash and trace elements

Acid rain has a pH


16/23

A redox equation is obtained by adding half-equations which have been

multiplied by factors so the number of electrons is the same in both half-

equations

18

Metals are found as minerals in ores. They are usually in an oxidised form

Metallurgy encompasses the process of mining, milling, extraction and refining.

Metal extraction involves reducing metal compounds to the metal

Two important methods of metal extraction are carbon reduction and electrolytic

reduction

Iron is mined in Australia mainly as hematite (Fe2O3). It is extracted by smeltingin a blast furnace. The reducing agent is carbon monoxide produced from coke.

Limestone is used to remove waste matter as slag

Cast iron, or pig iron, contains up to 5% carbon and is brittle, but forms sharp

casts

Steel is iron with less than 2% iron. It may have other metals alloyed with the

iron for special properties

Gold exists free in nature and combined with sulphur and tellurium. Gold is

extracted using the carbon-in-pulp process

Gold is a relatively inert metal

Chlorine exists in several oxidation states. In nature it ids found as chlorides in

the -1 state. It is prepared in the laboratory by oxidising concentrated

hydrochloric acid with manganese dioxide or potassium permanganate

Chlorine is very reactive. It is a strong oxidising agent and reacts with many

reducing agents including Mg, H2, H2S, SO2 and Fe2+

Chlorine disproportionate in aqueous and basic solutions to form chloride ion andhypochlorite ion. It is used extensively in bleaching and in water purification

Black and white photography utilises the reduction of silver ions in silver halides

on exposure to light

Redox titrations involve the reactions between oxidising agents and reducing

agents. They are frequently used in quantitative analysis

Potassium permanganate is a common oxidising agent. Because it is not a

primary standard, permanganate solution must be standardised before being

used for analysis. The purple colour of the MnO4-

ion makes an indicatorunnecessary in its redox titrations


17/23

Other common oxidising agents used in volumetric analysis are potassium

dichromate and iodine. Common reducing agents include oxalic acids or sodium

oxalate, ammonium iron (II) sulphate and sodium thiosulphate

19

In electrochemical cells stored chemical energy is converted to electrical

energy. A cell generates an emf that depends on the nature of the half-cell

reactions and the concentrations/gas pressures of the reacting substances

In an electrochemical cell, oxidation occurs in one half-cell that is called the

anode. It has the negative terminal. Reduction occurs in the other half-cell, called

the cathode. It has the positive terminal

20

An electrolytic cell operates under an applied emf. Electrical energy is used to

produce chemical change. In this sense electrolytic cells are the reverse of

electrochemical cells

In an electrolytic cell reduction occurs at the cathode and oxidation at the anode.

The cathode is labelled negative and the anode positive

Cations are positive ions which move towards the cathode. Anions are negativeions which move towards the anode

The products of electrolysis in aqueous solutions depend on the following:

relative E0 values of the possible half-reactions, whether inert of reactive

electrodes are used, and the concentration of the reactants

Electrolysis has applications in electro refining, electroplating, extraction of

reactive metals, manufacture of some chemicals, and in anodising

Copper is purified after extraction by electro refining

In the extraction of gold electrolysis is used to reduce the aurocyanide ion to

metallic gold

Electroplating involves the formation of a metal layer on an object used as the

cathode in an electrolytic cell. The plating metal is usually provided as the anode

which gradually dissolves into solution

Alumina is obtained from bauxite by the Bayer process. The mineral gibbsite is

leached using sodium hydroxide, crystallised out as pure Al(OH)2 and

decomposed by heating to produce alumina (Al2O3)


18/23

Aluminium is produced by the electrolytic reduction in the Hall-Heroult process.

Alumina and cryolite are melted and electrolysed. Molten aluminium is liberated

at the cathode. The carbon anodes burn away as gaseous carbon dioxide

Most of the uses of aluminium depend on such properties as its low density, good

conductivity of heat and electricity, resistance to corrosion and good reflectivity

Electrolysis of molten sodium chloride produces sodium and chlorine

Electrolysis of aqueous sodium chloride yields hydrogen, chlorine, and sodium

hydroxide

The quantity of electricity which flows through a circuit is measured in coulombs

and is given by the formula Q=It

The charge on one mole of electrons is 9.65 x 104 C. This is known as Faradays

constant or the faraday. The number of moles of electrons in a given charge iscalculated from the following formula: n(e) = Q/9.65 x 104

The mass of a substance or volume of a gas produced in electrolysis is directly

proportional to the quantity of electricity flowing and inversely proportional to

the number of electrons in the half-equation

When electrolytic cells are connected in series the same electric charge flows

through each cell

21

Organic chemistry and the chemistry of carbon are interchangeable terms which

apply to the study of carbon compounds other than metallic carbonates and

hydrogen carbonates and the oxides of carbon

Carbon is a non-metal element with four valence electrons and an electron

configuration of 2,4 or 1s2 2s22p2

Carbon froes a vast number of different compounds because of its ability to form

chains containing a succession of carbon-carbon bonds

Carbon can form single, double, or triple C-C bonds

The arrangement of atoms around a carbon atom is : four single bonds results in

a tetrahedral shape; one double bond and two single bonds result in a planar

shape, one triple bond and one double bond produce a linear shape

Some rules for bonding carbon-based compounds are: C must form 4 bonds,

halogens must form 1 bond, O must form two bonds, N must form 3 bonds, H

must form 1 bond


19/23

There are a number of ways to represent the structures of organic compounds:

electron dot diagrams, structural formulas, three-dimensional representations

22

Alkanes Alkenes Alkynes

General formula CnH2n+2 CnH2n CnH2n-2

Family name ane ene yne

MP/BP/density All relatively low but increase with increasing

molecular mass

Solubility in water All virtually insoluble

Reaction with

oxygen

Undergo combustion to form carbon dioxide and water

Reactivity Fairly unreactive Very reactive Fairly reactive

Alkyl groups are alkanes from which one hydrogen atom has been removed.

They are named using the stem name of the alkane from which they are

derived

Isomers are different compounds which have the same molecular formula. Thetypes are chain structural: different numbers of C atoms in longest chain;

position structural: functional groups located on different C atoms in chain;

geometric: relative positions of groups attached to C atoms joined by double

bond

Alicyclic hydrocarbons are cyclic hydrocarbons. These can be saturated or

unsaturated and have similar properties to the corresponding aliphatic

hydrocarbons

Aromatic hydrocarbons are those based on the parent compound benzene. The

unique structure of benzene involves the formation of two regions of delocalised

electron charge, containing a total of six electrons, located above and below the

plane of the molecule

Hydrocarbons are very important as fuels as shown by the use of natural gas,

petroleum and coal

Crude oil can be refined by fractional distillation to produce a variety of products

The quality of petrol can be determined from its octane number. This can be

improved by adding branched-chain alkanes, aromatics, some oxygen-containing

organic compounds and tetraethyl lead


20/23

23

Haloalkane

Ether Amine Alcohol Aldehyde Ketone

Carboxylic acid

Ester Amide

RX ROR RNH2 ROH RCHO RCOR

RCOOH RCOOR RCONH2

e.g.fluoro-

-oxy

-ane

-amine -ol -al -one -oic acid -yl

-oate

-amide

Dispersion

Dipole H-H H-H(strong)

Dipole Dipole

H-H(strong)

Dipole H-H

Goodsolvent

fats/oil

Slightly

soluble

Soluble

Soluble Slightlysoluble

Slightly

soluble

Soluble Slightlysoluble

Soluble

Low Higherthanalkanes

Lowerthanalcohols

Relatively high

Higherthanhydrocarbon/haloalkene/ether,but lowerthanalcohol

Asbefore

Relatively high

Lowerthanalcoholsandcarboxylic acids

Similartocarboxylic acids

Haloalkanes can be prepares by halogenations of an alkane

o RH + X2 + UV RX + HX

Hydrohalogenation of an alkene

o RCH=CH2 + HX RCHXCH3

Haloalkanes are fairly unreactive and are used as solvents for non-polar solutes

CFCs are one group of haloalkanes. They have been linked to ozone depletion

There are three classes of alcohols called primary, secondary and tertiary,

depending on how many alkyl groups are attached to the carbon atom to which

the OH group is attached

Alcohols can be prepared by the hydration of an alkene

o RCH=CH2 + H2O + H+RCHOHCH3

Alcohols can react with sodium to form sodium alkoxides and hydrogen

o 2ROH + 2Na 2RO-Na+ + H2

Different alcohols form different products when treated with oxidising agents

primary form aldehydes, which form carboxylic acids. Secondary oxidise to form

ketones.


21/23

Alcohols react with carboxylic acids to form esters

o RCOOH + ROH RCOOR + H2O

Methanol is the simplest alcohol, a good solvent, and very poisonous

Ethanol is the alcohol in drinks, produced by the fermentation of glucose

(C6H12O6)

Ethanol is produced industrially by the hydration of ethene in acidic conditions

Aldehydes can be prepared by oxidising primary alcohols

o RCH2OH RCHO + 2H+ + 2e-

Aldehydes can be further oxidised to carboxylic acids

o RCHO + H2O RCOOH + 2H+ + 2e-

Ketones can be prepared by oxidising secondary alcohols

o RCHOHR RCOR + 2H+ + 2e-

Ketones cannot be oxidised

Carboxylic acids are produced by the oxidation of primary alcohols and aldehyes

Carboxylic acids are weak acids; react with metals to form hydrogen gas; and

neutralise base

The strength of the acid depends on the length of the hydrocarbon chain and the

electro-negativities of any functional groups attached to the hydrocarbon chain

(e.g. Cl)

Carboxylic acids react with alcohols to form esters

o RCOOH + ROH (+H+) RCOOR + H2O

Fatty acids are long chain aliphatic carboxylic acids which are found in natural

esters in fats and oils. They can be saturated or unsaturated hydrocarbon chains

Esters are formed by the reaction of an alcohol and a carboxylic acid in the

presence of a strong acid like sulphuric acid

Esters can be hydrolysed in acid and alkaline conditions, giving different

products

Fats and oils are natural esters known as triglycerides. They are formed by the

reaction of 1,2,3-propanetriol, or glycerol, with fatty acids


22/23

24

Saponification is the soap making process in which an oil or fat is treated with

NaOH or KOH solution

Soaps are the sodium or potassium salts of fatty acids

Detergents are the salts of alkyl-benzene sulfonates

Soaps and detergents function as cleaning agents because the charged end of

the surfactant ion dissolves in the polar solvent water while the non-polar

hydrocarbon chain dissolves in the non-polar grease, oil or dirt

Soaps do not function effectively in hard water as the surfactant ion precipitates

out with the Ca2+ and Mg2+ ions. Detergents function in all types of water

Polymers are large molecules made up by bonding together small repeatingmolecules called monomers

There are two types of polymerisation processes, addition and condensation

Addition: small molecules with a C=C double bond join together, with a catalyst

Condensation: two monomers link together with the accompanying elimination

of a molecule of water. Often one monomer is a dicarboxylic acid and the other a

diamine or diol

Thermoplastics are polymers which can be softened by heating


23/23

Thermosetting plastics cannot be softened by heating after their initial shaping

and setting

Elastomers are polymers that can be stretched but return to their original shape

when the distorting force is removed

The structural formula of an unknown organic compound can be determined by

i. Determine qualitative composition (experimentally)

ii. Determine quantitative composition (experimentally)

iii. Calculate EF

iv. Determine relative molecular mass (experimentally)

v. Calculate molecular formula

vi. Determine structural formula

Reference:

All notes taken from:

J.D.Anderson, P.J.Garnett, W.R.Liddelow, R.K.Lowe, I.J.Manno. Foundations of Chemistry.

2nd ed. Melbourne: Pearson Education Australia; 1996.

Chemistry Chapter Summaries

Documents