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Lim Ting Jie
VS Class of 2011
Quick References
Website Chemistry
The Republished
2012 Edition
SECTION I: EXPERIMENTAL CHEMISTRY
1. Experimental Chemistry
1.1: Experimental design
(a) name appropriate apparatus for the measurement of time, temperature, mass and volume, including burettes, pipettes, measuring cylinders and gas syringes
Time/s Temperature/K or oC Mass/g Volume/cm3
Stopwatch Mercury thermometer (for laboratory readings -10 to 110oC) Temperature sensor & Datalogger (for more accurate readings)
Beam balance Electronic balance (for more accurate readings)
Beaker (fixed) Measuring cylinder (‡ 1 cm3) Pipette (‡ 0.1 cm3) Burette (fixed, 0.1 cm3)
(b) suggest suitable apparatus, given relevant information, for a variety of simple experiments, including collection of gases and measurement of rates of reaction
Collection of gases.
Insoluble gases Soluble gases Density of gases
Hydrogen
Carbon dioxide (slightly soluble)
Oxygen (very slightly soluble)
Ammonia
Chlorine
Hydrogen chloride
Sulfur dioxide
Gases less dense than air have molecular masses below 30
Gases denser than air have molecular masses above 30
Drying of gases.
Most gases except ammonia Hydrogen gas Ammonia gas
conc. H2SO4 CaCl2
CaO
1.2: Methods of purification and analysis
(a) describe methods of separations and purification for the components of the following types of mixtures: (i) solid-solid (ii) solid-liquid (iii) liquid-liquid (miscible and immiscible)
Point Sub Points What Content How Content Key Words
Solid-solid
Filtration Soluble solid from insoluble solid
Similar method to precipitation
1. one insoluble in water 2. other insoluble
Sublimation Solid that is able to sublime from solid that is unable to decompose when heated
Inverted funnel with a wet cloth on the sides over the heated evaporating dish
1. one able to sublime 2. the other unable to
decompose 3. inverted funnel 4. wet cloth 5. evaporating dish
Solid-liquid
Simple Distillation Solid from the liquid that it has dissolved in to obtain the liquid as it has a lower boiling point
Draw. The liquid will boil to become a gas and pass through the Liebig condenser to be condensed and collected as liquid in the beaker
1. solid dissolved in liquid 2. obtain liquid 3. boiling chips 4. liebig condenser 5. thermometer 6. beaker 7. round bottomed flask
Evaporation to dryness
Solid which does not decompose on heating from the liquid it has dissolved in to obtain solid
Heat the solution in an evaporating dish over Bunsen burner
1. solid dissolved in liquid 2. obtain solid 3. solid does not decompose 4. evaporating dish
Crystallisation Solid from water that it has dissolved in to obtain the solid crystals
Heat the solution until a hot saturated solution is formed, then allow solution to cool to room temp.
1. solid from water 2. obtain the solid crystals 3. hot saturated solution 4. allow to cool
Liquid-liquid
Simple Distillation Liquids of differing boiling points
As above 1. differing boiling points
Fractional distillation
Liquids of differing boiling points that are misible
As above, but with fractionating column
1. differing boiling points 2. misible 3. fractionating column
Separating funnel Immisible liquids of differing densities
Include two beakers in the experiment
1. differing densities 2. beakers
Paper chromatography
Liquids of differing solubilities
Paper soaks up, more soluble in solvent carried further away
1. differing solubilities
(b) describe paper chromatography and interpret chromatograms including comparison with ‘known’ samples and the use of Rf values
Point Content
Rf value Ratio of distance travelled by the substance to the distance travelled by solvent (front)
(c) explain the need to use locating agents in the chromatography of colourless compounds
Point Content
Use of locating agents To make colourless compounds visible so that their Rf value can be taken
(d) deduce from the given melting point and boiling point the identities of substances and their purity
Point Content
Effects of impurities
Decrease melting point
Increase boiling point
Changes state over a range of temperatures
1.3: Identification of ions and gases
(c) describe tests to identify the following gases
Points How Content What Content
Ammonia Bring the gas over damp red litmus paper Litmus paper turns blue
Carbon dioxide Bubble the gas through limewater A white precipitate will form in it
Chlorine Bring the gas over damp blue litmus paper Litmus paper turns red then bleached
Sulfur dioxide using acidified Potassium Dichromate(VI)
Turns from orange to colourless
SECTION II: ATOMIC STRUCTURE AND STOICHIOMETRY
2: The Particulate Nature of Matter
2.2: Atomic structure
(c) define proton (atomic) number and nucleon (mass) number
Point Content Mem Key words
Proton number The number of positively charged protons in an atom PA positively charged
Nucleon number The total number of protons and neutrons in an atom MN total number
(e) define the term isotopes
Point Content Mem Key words
Isotopes Atoms of the same element with the same number of protons but a different number of neutrons
No. of protons = no. of electrons
1. atoms 2. same element
2.3: Structure and properties of materials
(a) describe the differences between elements, compounds and mixtures
Element Atom Molecule Compound Mixture
Constituents One type of atom Smallest particle of an element
2 or more atoms
2 or more different elements
2 or more substances
Bonding - - Covalently bonded
Chemically combined Physically combined
Purity Pure substance Can still keep the chemical properties of that element
Pure substance
Pure substance -
Ratio - - - Fixed -
(d) deduce the physical and chemical properties of substances from their structures and bonding and vice versa
Point of comparison Giant ionic Simple covalent Diamond Graphite Giant metallic
Boiling and melting points High Low High High High
State in rtp Solid Liquid Or Gas Solid Solid Solid
Organic solvent solubility No Yes No No No
Electrical conductivity (molten)
Yes Generally No No Yes Yes
Electrical conductivity (solid) No Generally No No Yes Yes
Hardness Hard but brittle
N.A. Hard but brittle
Soft Hard and mallaeble
2.4: Ionic bonding
(a) describe the formation of ions by electron loss or gain in order to obtain the electronic configuration of a noble gas
Point Content
Oxidation and reduction
Atoms become ions by losing electrons through oxidation or gaining electrons through reduction in order to obtain an octet structure and become electronically stable.
(b) describe the formation of ionic bonds between metals and non-metals, e.g. NaCl; MgCl2
Formation of cations Formation of anions Formation of ionic bonds
A metal atom loses its valence electrons to form positively charged metal cation
A non-metal atom gains these electrons from the metal atom to form a negatively charged anion
The cations and anions have opposite charged and are attracted to one another by electrosatic attraction to form ionic bonds, holding the atoms of the ionic compound together
2.5: Covalent bonding (a) describe the formation of a covalent bond by the sharing of a pair of electrons in order to gain the electronic configuration of a noble gas
Atoms of non-metals share their electrons to form an octet structure through covalent bonds, reacting with one another in the process.
A covalent bond is the bond that is formed between atoms that share electrons.
2.6: Metallic bonding (a) describe metals as a lattice of positive ions in a ‘sea of electrons’
Point Definition
Metallic bond Force of attraction between positive metal ions and the ‘sea of delocalised electrons’
3. Formulae, Stoichiometry and the Mole Concept
(e) construct chemical equations, with state symbols, including ionic equations
Step Sequence
1 Write out the balanced equation, usually starting with the complex parts
2 Put in state symbols, with water-soluble compounds as aqueous
3 Write out free ions in the aqueuous solutions from their compounds
4 Cancel away spectator ions present on both sides of the equation
5 Write down the uncancelled formulas, with atoms and charges balanced
(f) define relative atomic mass, Ar (g) define relative molecular mass, Mr, and calculate relative molecular mass (and relative formula mass) as the sum of relative atomic masses (h) calculate the percentage mass of an element in a compound when given appropriate information
Point Symbol Definition
Relative atomic mass
Ar The number of times the mass of one atom of an element is greater than 1/12 of the mass of one carbon-12 atom
Relative molecular mass
Mr The mass of a molecule compared to 1/12 the mass of one carbon-12 atom (the relative atomic masses of all the atoms of the molecule)
(j) calculate stoichiometric reacting masses and volumes of gases (one mole of gas occupies 24 dm at room temperature and pressure); calculations involving the idea of limiting reactants may be set
Moles
Mass (g) Particles
Gas volume at r.t.p.
Mr 6 x 1023 24 dm3 / 24000 cm3
Moles Reactants Products
Equation Zn 2 HCl H2 ZnCl2
Before reaction 3 4 0 0
During reaction 2 4 2 2
After reaction 1 0 2 2
(i) calculate empirical and molecular formulae from relevant data
Element C H O Remarks
Percentage in compound (%) 39.1 8.7 52.2 By mass
Relative atomic mass 12 1 16 Use periodic table
Moles 3.26 8.70 3.26 Divide mass by Ar
Molar ratio 1 2.67 1 Divide by the smallest no. of moles
Simplest ratio 3 8 3 Multiply until constant k gives a 1 digit no.
SECTION III: CHEMISTRY OF REACTIONS
4. Electrolysis
(h) describe the electrolysis of aqueous copper(II) sulfate with copper electrodes as a means of purifying copper
Point What Content Usage Examples Ions conc
Inert electrode
Electrodes that do not take part in chemical reactions during electrolysis
Electrodes more reactive than the metal of the electrolyte will undergo a displacement reaction
Carbon, Graphite and Platinum
Decreases (Electrolyte conc decreases when in hydroxide discharge
Reactive electrode
Electrodes which take part in chemical reactions during electrolysis
Purification of a metal of low reactivity like using copper electrodes with copper solution
Metals also included in electrolyte
Remains the same
5: Energy from Chemicals
(b) represent energy changes by energy profile diagrams, including reaction enthalpy changes and activation energies (see 6.1(c),6.1(d))
6. Chemical Reactions
6.1: Speed of reaction
(d) state that some compounds act as catalysts in a range of industrial processes and that enzymes are biological catalysts (see 5(b), 6.1(c) and 10(d))
Catalysts in general Enzymes
Increase in temperature will result in increase of rate of reaction.
Increase in temperature will result in increase of rate of reaction.
But too low a temperature will cause itself to be inactive
Too high a temperature will cause itself to be denatured
May not be made of proteins Made of proteins
May not be specific in their actions Specific in their actions
6.2: Redox
(d) describe the use of aqueous potassium iodide and acidified potassium dichromate(VI) intesting for oxidising and reducing agents from the resulting colour changes
Oxidising agent Reducing agent
Acidified potassium manganate (VI) Acidified potassium dichromate
(VII)
Pale green Aqueous Iron (II) solution
Purple to pale yellow (due to presence of oxidising agent)
Orange to green
Sulfur dioxide gas Purple to colourless Orange to green
Hydrogen peroxide Purple to colourless, effervescence
seen Orange to green, effervescence
seen
Aqueous Sulphite solution Purple to colourless Orange to green
Aqueous Chloride solution
Purple to colourless, a choking yellowish-green gas changes moist
blue litmus paper to red then bleached
Orange to green, a choking yellowish-green gas changes moist
blue litmus paper to red then bleached.
Ea Reactants
Products ∆H = -ve
Ene
rgy/
kJ
Progress of reaction
7. Acids, Bases and Salts
7.1: Acids and bases
(a) describe the meanings of the terms acid and alkali in terms of the ions they produce in aqueous solution and their effects on Universal Indicator
Point Description
Acids Substances that react with water to produce hydrogen ions as the only positive ions
Bases Metal oxides or Metal hydroxides
Alkalis Soluble bases that react with water to produce hydroxide ions
(b) describe how to test hydrogen ion concentration and hence relative acidity using Universal Indicator and the pH scale
Measurement Hydrogen ion concentration test Relative acidity
Universal Indicator
Mixture of dyes that show red in high hydrogen ion concentrations and violet in high hydroxide ion concentration
At high hydrogen ion concentration, relative acidity will be high
pH probe or pH meter
Gives a reading from pH scale of pH value between 0 to 14. The lower the pH value, the higher the hydrogen ion concentration
(d) describe the characteristic properties of acids as in reactions with metals, bases and carbonates
(e) state the uses of sulfuric acid in the manufacture of detergents and fertilisers; and as a battery acid (j) classify sulfur dioxide as an acidic oxide and state its uses as a bleach, in the manufacture of wood pulp for paper and as a food preservative (by killing bacteria)
Sulfuric acid Sulfur dioxide
Manufacture of detergents Bleaching agent
Battery acid in cars Food preservative by killing bacteria
Manufacture of ferilisers Manufacture of wood pulp for paper
(h) describe the characteristic properties of bases in reactions with acids and with ammonium salts
7.2: Salts
(a) describe the techniques used in the preparation, separation and purification of salts as examples of some of the techniques
Reactants Products
Acid + Metal above hydrogen in reactivity series Hydrogen + Salt
Acid + Carbonate Carbon dioxide + Salt + Water
Acid + Base Salt + Water
Reactants Products
Base + Ammonium salt Ammonia gas + Water + Salt
Acid + Base Salt + Water
Conditions ‘ABCM’ Titration Precipitation
Salt Product
Soluble Yes Yes No
Ammonium Grp I No
Prepa-ration
Preparation Acid and Excess insoluble reactant
Acid and Exact souble reactant
Two aqueous solns
Gas and aq. soln
Sepa-ration
Combine and filter Obtain filtrate Obtain filtrate Obtain residue
Purifi-cation
Heat and cool Yes Yes No
Wash and dry With cool water With much water
Pre
cip
itat
ion
1.
Aq
ueo
us
solu
tio
n +
An
oth
er
2.
Aq
ueu
os
solu
tio
n +
Gas
Exce
ss a
mo
un
t o
f re
acta
nt
Titr
atio
n
1.
Aci
d +
So
lub
le b
ase
(Alk
ali)
2.
Aci
d +
So
lub
le c
arb
on
ate
Exac
t am
ou
nt
of
reac
tan
t
AB
CM
1.
Aci
d +
Inso
lub
le b
ase
2.
Aci
d +
Inso
lub
le c
arb
on
ate
3.
Aci
d +
Met
al
Exce
ss a
mo
un
t o
f re
acta
nt
(b) describe the general rules of solubility for common salts to include nitrates, chlorides (including silver and lead), sulfates (including barium, calcium and lead), carbonates, hydroxides, Group I cations and ammonium salts
By elimination: If the first step is not fufilled, go on until you reach step 3.
Step 1: Definite solubility Step 2: Solubility w/ exceptions Step 3: Not soluble
Alkali metals Nitrates Ammonium
Sulfates Halides Oxides Hydroxides Barium Calcium
Carbonates Hydrogen
Barium Calcium Lead (II)
Silver Lead (II)
Barium hydroxide Calcium hydroxide Hydrogen carbonate
7.3 Ammonia
(a) describe the use of nitrogen, from (fractional distillation of liquid) air, and hydrogen, from cracking oil (petroleum fractions), in the manufacture of ammonia
(c) describe the essential conditions for the manufacture of ammonia by the Haber process
Point Conditions Ideal
Temperature Low enough to prevent decomposition of ammonia
High enough to ensure a faster rate of reaction 450oC
Pressure Low enough to ensure low operating costs
High enough to prevent decomposition of ammonia
250 atm
Finely divided iron
Catalyst by lowering activation energy required to increase rate of reaction. Finely divided to increase surface area to volume ratio of iron atoms, increasing rate of reaction.
Fine
(d) describe the displacement of ammonia from its salts
Point Content
Displacement Ammonium salt + Alkali + Heat Ammonia gas + Water + Salt
SECTION IV: PERIODICITY
8. The Periodic Table
8.2: Group properties
(c) describe the elements in Group 0 (the noble gases) as a collection of monatomic elements that are chemically unreactive and hence important in providing an inert atmosphere, e.g. argon and neon in light bulbs; helium in balloons; argon in the manufacture of steel
Noble gas Functions
Helium Fill weather balloons (as it is non-flammable)
Neon Advertisement lights
Argon Fill light bulbs (as it does not oxidise the filament)
Krpton Lasik surgery
Xenon Car headlights
(d) describe the lack of reactivity of the noble gases in terms of their electronic structures
Noble gases already have full outershell electrons with a stable electronic configuration. It is hence unreactive. Any gain or loss or sharing of electrons will cause it to lose electronic stability.
9. Metals
9.1: Properties of metals
(b) describe alloys as a mixture of a metal with another element, e.g. brass; stainless steel
An alloy is a mixture of a metal with another element.
Alloy Constituent metals Uses
Brass Copper (70%) and Zinc (30%) Electrical wires
Bronze Copper (90%) and Tin (10%) Medals
Stainless steel 73% Iron, 8% Nickel, 18% Chromium and 1% Carbon Cultery (corrosion resistant)
9.2: Reactivity series (a) place in order of reactivity calcium, copper, (hydrogen), iron, lead, magnesium, potassium, silver, sodium and zinc by reference to (i) the reactions, if any, of the metals with water, steam and dilute hydrochloric acid, (ii) the reduction, if any, of their oxides by carbon and/or by hydrogen
Reaction Abbreviation Way to remember Metal range
Metal + Acid Hydrogen + Salt PL Patrol Leader K to Pb
Metal + Water Hydrogen + Metal Hydroxide PM Prime Minister K to Mg
Metal + Steam Hydrogen + Metal Oxide PI ∏, The Globe K to Fe
Reaction Abbreviation Way to remember Metal range
Metal Oxide + Carbon Metal + Carbon dioxide ZS Zoo Safari Zn to Ag
Metal Oxide + Hydrogen Metal + Steam IS hIS Fe to Ag
K P
Na S PM
Ca C
Mg M PL PI
Al A Carbon
Zn Z
Fe I
Sn T
Pb L ZS Hydrogen
Cu C IS
Hg M
Ag S
(b) describe the reactivity series as related to the tendency of a metal to form its positive ion, illustrated by its reaction with (i) the aqueous ions of the other listed metals (ii) the oxides of the other listed metals
The more reactive metal is able to displace the less reactive metal from its (i) aqueous salt solution or (ii) oxide in the reaction.
Special Cases: K, Na, Ca and Mg can react with water. Hence this reaction between the metal and water will predominate the displacement reaction, occurring first instead. For example, for the reaction between Na (s) and CuSO4 (aq), 2 Na + 2 H2O 2 NaOH + H2 occurring 1st. Thereafter, precipitation reaction occurs. 2 NaOH + CuSO4 Na2SO4 + Cu(OH)2.
(d) describe the action of heat on the carbonates of the listed metals and relate thermal stability to the reactivity series
Reaction Abbr Way to remember Metal range
Metal Carbonate, heated Metal Oxide + CO2 CC Community Club Ca to Cu
Metal Hydroxide, heated Metal Oxide + Steam CC Community Club Ca to Cu
Metal Oxide, heated Metal + Oxygen MP Member of Parliament Hg to Pt
9.5: Iron
(a) describe and explain the essential reactions in the extraction of iron using haematite, limestone and coke in the blast furnace
Step Description Equation
Preparation Stage
Coke [C], Haematite [Fe2O3 with impurities like sand] and Limestone [CaCO3] are added at the top of the blast furnace.
Blasts of hot air blown in from the base through pipes.
C + Fe2O3 + CaCO3 + SiO2
Coke Burning Exothermic reaction C + O2 CO2
CO Formation Endothermic reaction C + CO2 2 CO
Iron Ore Reduction
CO & CO2 escape through the top, burnt to provide heat for new blasts of hot air. Iron (l) containing carbon flows to the bottom.
Fe2O3 + CO Fe (l) + 3 CO2
Limestone Decomposition
Limestone is heated and decomposed to CO2 and basic oxide CaO, which will react with acidic oxide SiO2 later.
CaCO3 CO2 + CaO
Impurities Removal
Slag (l) floats on top of Iron (l). Both tapped off separately.
Slag mainly used for paving roads SiO2 + CaO CaSiO3 (l slag)
(b) describe steels as alloys which are a mixture of iron with carbon or other metals and how controlled use of these additives changes the properties of the iron, e.g. high carbon steels are strong but brittle whereas low carbon steels are softer and more easily shaped (c) state the uses of mild steel, e.g. car bodies; machinery, and stainless steel, e.g. chemical plants; cutlery; surgical instruments
Point High Carbon Steel Mild (Low Carbon) Steel Stainless Steel
Composition 0.45% C + Fe 0.25% C + Fe 1% C + Fe + Ni + Cr
Properties Strong but brittle Less strong and malleable Corrosion resistant
Uses Hammers Car bodies Industrial Pipes
Cutting Tools Machinery Surgical Instruments
(d) describe the essential conditions for the corrosion (rusting) of iron as the presence of oxygen and water
Rusting Rust Conditions Catalysts
Slow oxidation of iron into hydrated iron (III) oxide, Fe2O3·xH2O
A brittle reddish brown solid
Presence of:
Oxygen
Water
NaCl Common salt
SO2
CO2 Acidic pollutants
SECTION V: ATMOSPHERE
10. Air
(a) describe the volume composition of gases present in dry air
Point Content
Nitrogen approx 79%
Oxygen 20%
Carbon dioxide 0.03%
Argon 0.9%
Helium and Neon 0.002%
Water vapour Varying amounts below 5%
SECTION VI: ORGANIC CHEMISTRY
11: Organic Chemistry
11.1: Fuels and crude oil
(b) describe petroleum as a mixture of hydrocarbons and its separation into useful fractions by fractional distillation
How Fraction Remember Condensation
Petroleum is heated to 360oC in a furnace, evaporating in vapour
Liquified petroleum Long Light fractions have lower boiling points, collected at the top
Petrol Pea
Naptha Nuts.
Kerosene Kick Heavy fractions, higher boiling points, collected bottom
Diesel oil Dogs
Lubricating oil Laugh at
Bitumen Bulldog. Collected as residue
(c) name the following fractions and state their uses
Fraction Uses
Liquified petroleum Cooking, Heating
Petrol Motorcar engines
Kerosene Jet engines, Oil stoves, lamps
Diesel oil Diesel engines
Lubricating oil Lubricants, Waxes, Polishes
Bitumen Road surface paving
(d) state that the naphtha fraction from crude oil is the main source of hydrocarbons used as the feedstock for the
production of a wide range of organic compounds
Fraction Uses
Naptha Raw material (chemical feedstock) for chemical industries (e.g. detergents, medicines)
>
11.2: Alkanes
(b) describe the alkanes as an homologous series of saturated hydrocarbons with the general formula CnH2n+2
Point Content
Homologous series Family of organic compounds with similar chemical properties with a regular pattern
Saturated Hydrocarbons containing only single C-C covalent bonds
General formula CnH2n+2 with no functional group
(d) define isomerism and identify isomers
Point Content Examples
Isomers Organic compounds with the same molecular formulae but different structural formulae
Methylpropane and Butane are isomers.
But-1-ene and But-2-ene are isomers.
(e) describe the properties of alkanes (exemplified by methane) as being generally unreactive except in terms of
burning and substitution by chlorine
Point Content
Alkanes are unreactive Carbon-carbon and Carbon-hydrogen are strong and difficult to break.
Except in burning Complete: Methane + Oxygen (with heat) Carbon dioxide + Water vapour Incomplete: Methane + Oxygen (with heat) Carbon monoxide + Water vap.
Except in substitution Methane + Chlorine (UV light) Chloromethane + Hydrogen chloride (Cl atom replaces a H atom)
11.3: Alkenes
(a) describe the alkenes as an homologous series of unsaturated hydrocarbons with the general formula CnH2n
Point Content
Saturated Hydrocarbons containing only double (C=C) or triple (CΞC) covalent bonds
(c) describe the manufacture of alkenes and hydrogen by cracking hydrocarbons and recognise that cracking is
essential to match the demand for fractions containing smaller molecules from the refinery process
Point Cracking of Products Importance
Main reaction Alkane Alkene + Alkane of shorter chain Short-chained alkanes are used as
petrol Alkane Alkene + Hydrogen
Side reaction Alkane Alkene + Alkene + Hydrogen Hydrogen used to make ammonia
Catalysts Al2O3 (amphoteric), SiO2 (acidic giant covalent) Speed up cracking process
(d) describe the difference between saturated and unsaturated hydrocarbons from their molecular structures and by
using aqueous bromine
Point Saturated hydrocarbon Unsaturated hydrocarbon
Double bonds Contain only single bonds between carbon atoms Contain double bonds between carbon atoms
Reactivity Generally unreactive (The carbon-hydrogen and carbon-carbon bonds are unreactive)
Very reactive (The carbon-oxygen and oxygen-hydrogen bonds are more reactive)
Reactions Substitution reactions Addition polymeristion
Combustion Produce less smoky flames than alkanes with same numbers of carbon atoms as they have a higher percentage of carbon atoms per mole
Produce smokier flames than alkanes with same numbers of carbon atoms
Aqueuous bromine
Do not react with bromine solution under normal conditions
Decolourises aqueous orange-brown bromine solution
(e) describe the properties of alkenes (exemplified by ethene) in terms of combustion, polymerisation and the
addition reactions with bromine, steam and hydrogen
Point Reactants Conditions Products
Combustion Alkene + Oxygen Heat, Air in plentiful supply Carbon dioxide + Water vap
With hydrogen Alkene + Hydrogen 200oC, Nickel catalyst Alkane
With steam Alkene + Steam 300oC, 60 atm, Phosphoric IV acid Alcohol
With bromine Alkene + Bromine Normal conditions Bromoalkane
Polymerisation Occurs when monomer units join together without losing any molecules or atoms
(f) state the meaning of polyunsaturated when applied to food products
Point Meaning
Polyunsaturated Food products by which their hydrocarbon chains contain more than one carbon-carbon double bond
(g) describe the manufacture of margarine by the addition of hydrogen to unsaturated vegetable oils to form a solid product
Point Manufacture additives
Production of margarine Hydrogen + Vegetable oil + 200oC + Nickel catalyst
Purpose Hardening Main constituent Heat Catalyst
11.4: Alcohols
(a) describe the alcohols as an homologous series containing the -OH group
(c) describe the properties of alcohols in terms of combustion and oxidation to carboxylic acids
Point Reactants Conditions Products
Combustion Alcohol + oxygen Heat, plentiful oxygen Carbon dioxide + Steam
Oxidation Alcohol + oxygen from oxidising agent Heat Carboxylic acid + Water
Bacterial Ethanol + oxygen in air Bacteria presence Ethanoic acid + Water
Oxidising agents
Acidified potassium dichromate (VI) changes from orange to green (OG) Acidified potassium manganate (VII) changes from purple to colourless (PC)
Reduces 2 O atoms
(d) describe the formation of ethanol by the catalysed addition of steam to ethene and by fermentation of glucose
Point Reactants Conditions Products
Catalysed addition of steam Ethene + Steam 300oC, 60 atm, Phosphoric IV acid Ethanol
Fermentation of glucose Glucose solution 37-40oC, Absence of oxygen Ethanol + CO2
Max 20% ethanol
(e) state some uses of ethanol, e.g. as a solvent; as a fuel; as a constituent of alcoholic beverages
Uses Content
Solvent Good solvent to dissolve substances insoluble in water
Evaporates quickly
Fuel Reactants Product Function
85% Ethanol + 5% Methanol + 10% Water Methylated spirit Cooking, lamps
Ethanol + Petrol Fuel Run motor vehicles
Alcholic beverages by fer-mentation
Barley starch solution 3-8% Ethanol + CO2 Beer
Barley starch solution + Fractional distill. 30-60% Ethanol + CO2 Whisky
Grapes starch solution 8-18% Ethanol + CO2 Wine
Grapes starch solution + Fractional distill. 30-60% Ethanol + CO2 Brandy
11.5: Carboxylic acids
(c) describe the carboxylic acids as weak acids, reacting with carbonates, bases and some metals
Reaction with Reactants Products
Carbonates Ethanoic acid + Metal carbonate Metal ethanoate + Carbon dioxide + Water
Bases Ethanoic acid + Base Metal ethanoate + Water
Metals Ethanoic acid + Reactive metal (PM) Metal ethanoate + Hydrogen
1. Carboxylic acids ionise only partially in water to form hydrogen ions, hence they are weak acids
2. The hydrogen ions that are formed in water give carboxylic acids their acidic properties.
To form the metal ethanoate, 1. Take away the ending H atom from acid 2. Then C...H...COO- + Metal ion Ethanoate
(d) describe the formation of ethanoic acid by the oxidation of ethanol by atmospheric oxygen or acidified potassium dichromate(VI)
Point Reactants Conditions Products
Oxidation Alcohol + Oxygen from oxidising agent Heat Carboxylic acid + Water
Bacterial Ethanol + Oxygen in air Bacteria presence Ethanoic acid + Water
Oxidising agents
Acidified potassium dichromate (VI) changes from orange to green (OG) Acidified potassium manganate (VII) changes from purple to colourless (PC)
Reduces 2 O atoms
(e) describe the reaction of a carboxylic acid with an alcohol to form an ester, e.g. ethyl ethanoate
Esterification Description of formation
The reaction of a carboxylic acid with an alcohol to form an organic compound known as an ester (through warming and presence of few drops of concentrated sulfuric acid as a catalyst)
The -OH group of the carboxylic acid of is replaced the CnH2n+1O- group of an alcohol.
Point Reactants Conditions Products
Esterification Alcohol + Carboxylic acid Heat, Conc sulfuric acid Ester + Water
(f) state some commercial uses of esters, e.g. perfumes; flavourings; solvents
Characteristics Suitable for
Colourless, netural, water insoluble, sweet and fruity smell Perfumes and artificial food flavourings
Cosmetics and glues constituents soluble in organic solvents Solvents for cosmetics and glues
11.6: Macromolecules
(a) describe macromolecules as large molecules built up from small units, different macromolecules having different units and/or different linkages
Point Definition / Description Key words
Monomer A small molecule that can be joined together to form a polymer (larger molecule)
1. Small molecule 2. Can join to form polymer
Polymer A macromolecule (long-chain molecule) made up of many monomers (small molecules) joined together
1. Macromolecule 2. Monomers joined together
Macromolecule A long-chain molecule that contains hundreds or thousands of atoms joined together by covalent bonds
1. Long-chain 2. 103 or 104 s of atoms 3. Covalently bonded
Polymerisation Process of joining together a large number of monomers (small molecules) to form a macromolecule (large molecule)
(b) describe the formation of poly(ethene) as an example of addition polymerisation of ethene as the monomer
Point Definition / Description
Addition polymerisation
Process of joining together monomer units without using any molecules or atoms
General reaction Thousands of alkene molecules Polymer (at 200oC, 1000 atm)
Example Thousands of ethene molecule Poly(ethene) (at 200oC, 1000 atm, Ziegler’s catalyst)
Step to form poly(ethene) Definition / Description
1. Bond breaking One bond in the double bond of each ethene molecule breaks
2. Bonding with other monomers Each ethene molecule forms single bonds with two other monomers
3. Poly(ethene) formed Poly(ethene) is formed under high pressure and temperature
(c) state some uses of poly(ethene) as a typical plastic, e.g. plastic bags; clingfilm
Characteristics Suitable for
Flexible but difficult to break Plastic bags
Clingfilm
(e) describe nylon, a polyamide, and Terylene, a polyester, as condensation polymers, the partial structure representations of nylon and that of Terylene
Point Nylon Terylene
Type Polyamide Polyester (poly-ester, ‘many ester linkages’)
Reactants Dicarboxylic acid (2 -COOH)
Diamine (2 -NH2)
Dicarboxylic acid (2 -COOH)
Diol (2 -OH)
Specific reactants
- Benzene-1, 4-Dicarboxylic acid
Ethane-1, 2-Diol
Functional group Amide group
Ester functional
group ―COO―
―CONH―
Partial structure
(g) describe the pollution problems caused by the disposal of non-biodegradable plastics
Problems Fires spread Produces poisonous gases when spread Non-biodegradable Air pollution
Description Modern buildings are insulated and furnished with plastic
Contains carbon compounds
Highly flammable
Cannot be decomposed by bacteria in soil
Land pollution
PVC produces hydrogen chloride gas
Solutions Reuse or recycle plastics
Summary of reactions in organic chem
Reactants Products Conditions Catalysts Alkane + Oxygen in air Carbon dioxide + Water vapour Heat, abundant oxygen supply -
Alkene + Oxygen in air Carbon dioxide + Water vapour Heat, abundant oxygen supply -
Alcohol + Oxygen in air Carbon dioxide + Steam Heat, abundant oxygen supply -
Alkane + Oxygen when incomplete Carbon monoxide + Water vapour Heat, limited supply of oxygen - Alcohol + Oxygen from oxidising agent Carboxylic acid + Water Heat -
Ethanol + Oxygen in air Ethanoic acid + Water Presence of bacteria - Alkane main cracking reaction Alkene + Alkane of shorter chain 600oC Al2O3/SiO2
Alkane possible cracking reaction Alkene + Hydrogen 600oC Al2O3/SiO2 Alkane side cracking reaction Alkene + Alkene + Hydrogen 600oC Al2O3/SiO2
Alkane + Chlorine Chloroalkane + Hydrogen chloride UV light - Alkene + Hydrogen Alkane 200oC Nickel
Vegetable oil + Hydrogen Margarine 200oC Nickel Alkene + Bromine Bromoalkane - -
Alkene + Steam Alcohol 300oC, 60 atm Phosphoric (IV) acid Glucose solution dilute 15% Ethanol + Carbon dioxide 37-40oC, Absence of oxygen Yeast (enzyme)
Alcohol + Carboxylic acid Ester + Water Heat Concentrated Sulfuric acid