2 Energy levelis the fixed energy value that an electron in an atom may have.Exam Q (Hons)‘08/Q10c‘07/Q4
3 Ground State lowest energy state ( in 1s orbital) Excited state = higher energy stateExam Q (Hons)08/Q10c
4 An orbitalis a region in space within which there is a high probability of finding an electron.Exam Q (Hons)‘06/Q5
5 An elementis a substance that cannot be split up into simpler substances by chemical means.
6 A triadis a group of three elements with similar chemical properties in which the atomic weight of the middle element is approximately equal to the average of the other two.(Dobereiner)
7 Newlands’ Octavesare groups of elements arranged in order of increasing atomic weight, in which the first and the eighth element of each group have similar properties.
8 Mendeleev’s Periodic Law When elements are arranged in order of increasing atomic weight (relative atomic mass), the properties of the elements vary periodically.
9 The atomic number(Z)is the number of protons in the nucleus of that atom.
10 Periodic Tableis an arrangement of elements in order of increasing atomic number.
11 Elements are arrangedin order of increasing atomic number, the properties of the elements vary periodically.
12 Mass number (A)is thesum of the number of protons and neutrons in the nucleus of an atom of that element.
13 IsotopesExam Q (Hons)’06/Q10aare atoms of the same element ( i.e. they have the same atomic number) that have different mass numbers due to the different number of neutrons in the nucleus.
14 Relative Atomic Massis the average of the mass numbers of the isotopes of the elementas they occur naturallytaking their abundances into accountrelative to 1/12th mass of carbon 12 atom(expressed on a scale in which the atoms of carbon 12 isotope have a mass of exactly 12 units).Exam Q (Hons)’06/Q10a
15 Mass Spec. V I A S D Vaporisation how? why? Ionisation Acceleration SeparationVictorA+Detection
16 Aufbau Principlethat when building up the electronic configuration of an atom in its ground state, the electrons occupy the lowest available energy level.
17 Hund’s Rule of Maximum Multiplicity states thatwhen two or more orbitals of equal energy are available,the electrons occupy them singly first before filling them in pairs.
18 Pauli Exclusion Principle that no more than two electrons may occupy an orbital and they must have opposite spins.
19 Compoundis a substance that is made up of two or more different elements combined together chemically.
20 Octet Rulethat when bonding occurs, atoms tend to reach an electron arrangement with eight electrons in the outermost shell.
22 An Ionic bondis the force of attraction between oppositely charged ions in a compound.
23 A transition metalis one that forms at least one ion with a partially filled d sublevel.
24 Moleculeis a group of atoms joined together. It is the smallest particle of an element or compound that can exist independently.
25 Valency of an elementis defined as the number of atoms of hydrogen or any other monovalent element with which each atom of the element combines.
26 Electronegativityis a measure of the relative attraction that an atom in a molecule has for the shared pair of electrons in a covalent bond.Exam Q (Hons)’06/Q5
27 Electronegativitydifference > 1.7 indicates ionic bonding in a compound.An electronegativity difference ≤ 1.7 indicates covalent bonding in a compound.
28 The value of electronegativity decrease down the groups in the Periodic Table for two reasons:increasing atomic radiusscreening effect of inner electrons
29 The values of electronegativity increase across the periods in the Periodic Table for two reasons:increasing nuclear chargedecreasing atomic radiusF= most electronegative element.Halogens –decrease in reducing power down the group due to drop in electroneg. values.
30 Intermolecular Forces attractive (repulsive) forcesbetween moleculesIntramolecular forces areattractive (repulsive) forces within a molecule
31 Vans der Waals Forcesare weak attractive forces between molecules resulting from the formation of temporary dipoles.
32 Dipole-dipoleDipole – dipole forces are forces of attraction between the negative pole of one molecule and the positive pole of another.
33 Hydrogen bondsare particular types of dipole-dipole attractions between molecules in which hydrogen atoms are bonded to nitrogen, oxygen or fluorine.The hydrogen atom carries a partial positive charge and is attracted to the electronegative atom in another molecule. Thus, H acts as a bridge between two electronegative atoms.
34 The Law of Conservation of Mass the total mass of the products of a chemical reaction is the same as the total mass of the reactants.
35 The Law of Conservation of Matter that in any chemical reaction, matter is neither created nor destroyed but merely changes from one form into another.
36 Tests for Anions Chloride Sulfate/sulfite carbonate/hydrogen carbonate nitratephosphate(NB know confirmatory test too!)
37 Chloride Add AgNO3 Get white ppt Confirm = ppt dissolves in dilute ammoniaEquation needed
38 Sulfate/sulfite Add BaCl2 Get white ppt Distinguish add dil HCl to white pptppt remains = sulfateppt dissolves = sulfiteEquation needed !!
39 CO32- /HCO3- Add dil. HCl (or any acid) Get bubbles of CO2 (limewater milky)DistinguishaddMgSO4 to fresh solutionwhite ppt. immediately = carbonatewhite ppt on heating = hydrogen carbonateEquation needed !!
40 Nitrate Brown Ring Test Add fresh FeSO4 At slant add conc. H2SO4 drop wiseGetbrown ring at junction of 2 layersNo equation needed
41 Phosphate Add ammonium molybdate 5 drops of conc. nitric acid (warm the solution)Get yellow pptNo equation neededConfirm: Goes colourless when add dilute NH3
42 The atomic radius of an atom is defined as half the distancebetween the nuclei of two atomsof the same element that arejoined together by a single covalent bond.Exam Q (Hons)07/Q4
43 The values of atomic radius increase down any one group in the Periodic Table for two reasons:extra shellscreening effect of inner electrons
44 The values of atomic radius decrease from left to right across a Periodic Table for two reasons:increasing nuclear chargeno increase in screening effect
45 The first ionisation energy of an atom is the minimum energy requiredto completely removethe most loosely bound electronfrom one mole of neutral gaseous atomin the ground state.******2004 =9 marks (2.25%)2002 = 8marks(2%)
46 The values of ionisation energy decrease down the groups in the Periodic Table for two reasons:increasing atomic radiusscreening effect of inner electrons
47 The values of ionisation energy increase across the Periodic Table for two reasons:increasing nuclear chargedecreasing atomic radius
48 More on ionisation energy First Ionisation EnergyM – e- M+Second Ionisation energyM+ – e- M2+Major jump in I.E. values – significance
49 The value of electronegativity decrease down the groups in the Periodic Table for two reasons:increasing atomic radiusscreening effect of inner electrons
50 The values of electronegativity increase across the periods in the Periodic Table for two reasons:increasing nuclear chargedecreasing atomic radiusF= most electronegative element.Halogens –decrease in reducing power down the group due to drop in electroneg. values.
51 A gasis a substance that has no well-defined boundaries but diffuses rapidly to fill any container in which it is placed.
52 Radioactivity is the spontaneous breaking up of unstable nuclei with the emission of one or more types of radiation.
53 Alpha particles loss of He nucleus (2p + 2n) mass number down by 4 atomic number down by 2element changes to element two places back
54 Beta particle neutron changes to proton and electron electron emitted mass number stays sameatomic number drops by oneelement changes into element one place back
55 Gamma radiation no new atoms formed (no transmutation) only energy lost
56 Half Life of an element is the time taken for half the nuclei in any given sample to decay.
57 Moleis the amount of a substance which contains 6 X 1023 particles of that substance(avogadro’s number or constant =L)
58 a few numbers Kelvin = Celsius + 273 standard temp = 273 K standard pressure = 1X105 Pa(100kPa)m3 = litres X10 -3m3 = cm3 X10 -6(1 litre = 1000cm3)
59 Mole contains 6 X 1023 particles has mass equal to Ar or Mr in grams occupies 22.4 litres at s.t.p (if gas)
60 Boyle’s Law states that: at constant temperature, the volume of a fixed mass of gas isinversely proportional to its pressure.
61 Charles’ Law states that: at constant pressure, the volume of a fixed mass of a gasis directly proportional to its temperature measured on the Kelvin scale.
62 General Gas Law P1 X V1 = P2 X V2 T1 T2 Temp in Kelvin Units for volume same each sideUnits for pressure same each side
63 Gay Lussac’s law of Combining Volumes the volumes of the reacting gases and the volumes of any gaseous products arein the ratio of small whole numbersprovided the volumes are measured at the same temp and pressure
64 Avogadro’s Law states that equal volumes of gases contain equal numbers of molecules under the same conditions of temp. and pressureExam Q (Hons)‘07/Q10b
65 Molar Volume At s.t.p one mole of any gas occupies 22.4 litres Remember to watch out for r.t.p in questionsroom temp. and press = as given in Q(often 24 litres)
66 Ideal Gas is one which perfectly obeys Exam Q (Hons)’06/Q11ais one which perfectly obeysall the gas laws and all the assumptions* of the kinetic theory of gasesunder all conditions of temperature and pressure.(Know the assumptions)
67 Real v. ideal gasReal gases differ from ideal gases at high pressure and low temp. becausethere are forces of attraction/repulsion between the molecules*the volume of the molecules is not negligible compared to the distances between them(*know examples of real gases and the forces involved)
68 Empirical Formulagives the simplest whole number ratio of the numbers of the different atoms present in the molecule.(divide by Ar and get ratio)(molecular formula is a simple multiple of the empirical formula)
69 Acids / Bases Arrhenius Acid + Base Bronsted Lowry Acid + Base NeutralisationConjugate Acid/ conjugate baseconjugate pair
70 Arrhenius Acid and Base is a substance that dissociates in water to produce H+ ions.Arrhenius Baseis a substance that dissociates in water to produce OH- ions.
71 Bronsted Lowry Acid /Base is a proton (H+) donorBronsted Lowry Baseis a proton (H+) acceptorExam Q (Hons)’07/Q7
72 Neutralisation is the reaction between an acid and a base forming a salt and water(acid + base -> salt + water)SALT = is formed when the H of an acid is replaced by a metal
73 Conjugate Acid / Conjugate Base is formed when a base accepts a protonConjugate Baseis formed when an acid donates a proton.
74 Conjugate Pair an acid and a base that differ by a proton Exam Q (Hons)‘07/Q7
75 Primary Standard is a substance of high Mr which can be obtained in a pure stable soluble solid formso that it can be weighed out anddissolved in water to givea solution of accurately known concentration.(Know why high Mr matters)
76 Titration is a laboratory procedure where a a measured volume of one solution is added toa known volume of another solution until the reaction is complete.(concentration of one solution known accurately at start)(indicator used to show by colour change when reaction is complete)
78 Definitions Oxidation is addition of loss of increase in Exam Q (Hons) ‘08/Q10(b)’06/Q10(b)oxygenelectronsoxidation number
79 Reduction is loss of oxygen gain of electrons decrease in oxidation number
80 More…An oxidising agent causes oxidationand is itself reduced.A reducing agent causes reductionand is itself oxidised.What is a redox reaction?
81 What is oxidised and reduced in each of the following? Br2 + 2Fe 2+ → 2Br– + 2Fe 3+Cu 2+ + Zn Cu + Zn 2+2Na + Cl2 2NaCl
82 Oxidation Number Rules The oxidation number ofan Element isgroup One elements is +1group Two elements is +2incompounds
83 The oxidation number of an ion is equal to thecharge on the ionhalogens is-1 (in binary compounds)(except ……????)
84 The oxidation number of H in a compound is +1exceptin metal hydrides when it is -1
85 The oxidation number of O in a compound is -2except (x2)in peroxides when it is -1 (H2O2)in OF2 when it is +2 (why?)
86 Oxidation numbers add up to zero in a compound add up to the charge of a complex ion
87 What is the oxidation number of each element in :- MnO4¯I2KBrO3Na2S2O3H2O2NaClO
88 KMnO4 (end point = first permanent pink) oxidising agent purple read top of meniscusis reduced fromMn (VII) Mn (II) in presence of H+purple colourlessown indicator(end point = first permanent pink)
89 KMnO4 not primary standard (x2) get brown Mn (IV) if H+ absent(which acid MUST be used – why x2)not primary standard (x2)standardised by titrating against standard solution of acidified Fe 2+
90 H2SO4added during KMnO4 titrations to provide H+ and ensure the complete reduction of Mn (VII) Mn (II)and prevent formation of Mn (IV)(brown)added during prep. of Fe (II) solutions toprevent oxidation of Fe 2+ to Fe 3+ by oxygen in the air ( why does this matter?)
91 Na2S2O3 S2O3 2- ion reducing agent used in photography not primary standard – why ?standardised by titrating against I 2starch indicator – when added and whycolour change at end point ?
92 Iodine I2 Oxidising agent NOT a primary standard (X2) Produced when MnO4- oxidises I- to I2(known concentration) (in excess)Starch indicator – when added? why then?Colour change at end pointBlue/black to colourless
93 remember dilution factor Bleachsodium hypochlorite Na+ClO-bleach diluted x10 with distilled waternot de-ionised water (why? )ClO- oxidises I- to I2I2 v. thiosulfatestarch indicator as beforeNBremember dilution factorin calculations
95 Rates of Reactions The rate of reaction is the change in concentration Exam Q (Hons)2003 Q72004 Q82007/Q92011 /Q5The rate of reaction isthe change in concentrationper unit time of any one reactant or product.
96 Factors affecting rate nature of reactantsparticle sizeconcentrationtemperaturecatalysts
97 Equations to know Write each equation then check Decomposition of hydrogen peroxide using manganese dioxide as catalystMnO22H2O2 2H2O + O2Sodium thiosulfate and hydrochloric acidNa2S2O7 + 2HCl S + 2NaCl + SO2 +H2O
98 Rate Graphs Concentration v. ( 1 /Time ) or Temp v. ( 1 /Time ) ( 1 /Time )used as Rate and Time inversely related(shorter time means faster rate)be careful with units of 1/time
99 Catalyst is a substance that alters the rate of reaction Exam Q (Hons)2003 Q7‘07/Q9is a substance that alters the rate of reactionbut is not consumed in the reaction.
100 Homogeneous catalysis occurs when the reactants and the catalyst are in the same phase.example =?liquidsKI catalyses 2H2O2 2H2O + O2 (iodine snake)And any enzyme
101 Heterogeneous catalysis Exam Q (Hons)‘07/Q4occurs when the reactants and the catalyst are in different phases.(NB must be phases not states)example = ?Al2O3 (solid)catalysesethanol (gas) etheneMethanol methanal using platinum
102 Autocatalysisoccurs when one of the products of the reaction catalyses the reaction.Example = ?Mn2+ ions in KMnO4 titrations(purple changes to colourless more quickly as titration proceeds)
103 Mechanism of Catalysis Intermediate Formation theorySurface Adsorption theoryKnow details of each and evidence of intermediate formation theory
104 Enzymes Are biological catalysts made of protein Examples of homogeneous catalysisNeed to know 2 examplesAmylase catalyses conversion of starch to maltoseCatalase catalyses conversion of hydrogen peroxide to hydrogen and water
105 Learning Check Do I know Definition for Rate of reaction Catalyst Homogeneous catalysisHeterogeneous catalysisAuto catalysisTwo mechanisms of catalysisPress enter to continue
106 Catalytic converter Catalysts = ? Pt + Pd + Rh on honeycomb surface (ceramic)Gases inCONONO2hydrocarbonsGases outCO2 and N2 and H20
107 Learning Check Do I know 3 metals in Catalytic converter 4 wastes in exhaust fumesProblem of eachWhat each is converted toWhat poisons catalytic converterType of catalysis occuring in catalytic converterPress enter to continue
108 Collision Theoryfor a reaction to occur the reacting particles must collide with each othera collision only results in a product being formed if a certain minimum energy is exceeded (called activation energy)
109 Effective Collision Is one in which a reaction occurs Exam Q (Hons)2009 Q9Is one in which a reaction occursThe activation energy has been reached or exceeded.
110 Activation Energyis the minimum energy which colliding particles must have for a reaction to occur(minimum energy required for effective collisions between particles)Exam Q (Hons)2006/Q72009/Q9
111 Activation Energy 2Catalysts lower the activation energy of a reactionCompare E actWithout catalystwith catalyst
112 Energy Profile Diagram Sketch an energy profile diagram for an endothermic reaction.Press enter when ready andIt should look like this
113 Endothermic Energy Profile Diagram ProductsActivation EnergyEnergy InReactantsNote – axes should be labelled Time (x) and energy (y)Curve should be smooth !
114 Energy Profile Diagram Sketch an energy profile diagram for an exothermic reaction.Press enter when ready andIt should look like this
115 Exothermic Energy Profile Diagram Activation EnergyReactantsEnergy OutProductsNote – axes should be labelled Time (x) and energy (y)Curve should be smooth !
116 Learning Check Do I know Definition for Effective collisionActivation energyCan I draw energy profile diagram forExothermic reactionEndothermic reactionEither of above with catalystThe End
117 Chemical Equilibriumis a state of dynamic balance where the rate of the forward reaction equals the rate of the reverse reaction.
118 Le Chatelier’s Principle If a stress is applied to a system at equilibriumthe system readjusts to oppose the stress appliedreactions at equilibrium // oppose the applied stress(es)*Exam Q (Hons)’06/Q11b
119 Le Chatelier’s Principle and Gases Le Chatelier’s Principle predicts thatin an all-gaseous reactionan increase in pressurewill favour the reaction which takes place with a reduction in volume( towards the side with the smaller number of molecules)
120 Equilibrium Constant Kc [ ] means concentration in moles per litre [ C] c x [D]dKc = for aA + bB cC + dD[A]a x [B]b(product of products conc.overproduct of reactants conc.)
121 Le Chatelier and Industry Ammonia and Haber Processpredict max yield at high press. /low tempreality = 200 atm and 500o CSulfuric Acid and Contact Processreality = one atm and 450oC
122 Kc large Kc => equilibrium far to right (lots of product produced) small Kc => equilibrium far to left(v. little product formed)must quote temp.units – depend on reactiontells us how far not how fast a reaction occurs
124 Kw Kw = [H+].[OH-] Also remember Kw = 1x10-14 ( at 25oC) ([H+] = √Kw) so [H+]= 1x10-7and pH =7Exam Q (Hons)08/Q8
125 Strong / Weak acid A strong acid is a good proton donor or (is fully dissociated into ions in dilute aqueous soln.[H+] = [acid] HCl[H+] = 2x[acid] H2SO4 etcA weak acid is a poor proton donoror (slightly dissociated into ions in dil. aq. soln.)[H+] = √Ka x MacidExam Q (Hons)‘07/Q7
126 Strong / Weak baseA strong base is a good proton acceptor or one which is fully dissociated into ions in dilute aqueous solution[OH-] = [base] NaOH[OH-] = 2x[base] Ca(OH)2 etcA weak base is a poor proton acceptor or one which is slightly dissociated in dli. aq. soln.[OH-] = √Kb x Mbase
127 IndicatorAn acid base indicator is a substance that changes colour according to the pH of the solution it is in.(equilibrium HIn ↔ H+ + In-)
128 Methyl orange in acid (lower pH ) red in base ( higher pH) yellow
129 Phenolphthalein in acid (lower pH ) colourless in base ( higher pH) pinkrangepH 8-11
130 Litmus in acid (lower pH ) red in base ( higher pH) blue range pH 5-8 (Not as reliable as others for accurate work)
131 Which indicator ? strong acid/strong base = methyl orange / phenolphthalein /litmus( see above)strong acid / weak base =methyl orangeweak acid /strong base =phenolphthaleinweak acid / weak base =none (why?)
132 Hard Water is water that will not easily form a lather with soap due to the presence of Ca 2+ or Mg 2+ ions in solution.Exam Q (Hons)’06/Q8
133 Temporary Hardness can be removed by boiling the water due to Ca(HCO3)2becomes CaCO3 on heatingleads to blocked pipes etc
134 Permanent Hardness is not removed by boiling the water caused by CaSO4 or MgSO4
135 Methods of removing hardness boiling (only works for temp. hardness)distillationwashing sodaion exchange
136 Calculations Total hardness = calcium hardness + magnesium hardness butDo calculations as if all hardness caused by CaCO3expressed in p.p.m of CaCO3p.p.m. = mg/litre
137 Water Treatment screening flocculation sedimentation filtration chlorinationfluoridationpH adjustment
138 B.O.D Biochemical Oxygen Demand is the amount of dissolved oxygen consumed by biological actionwhen a sample of water is keptat 20oCin the darkfor five days.(know reason for each of 3 conditions)
139 Eutrophicationis the enrichment of water with nutrients which leads to the excessive growth of algae.Nutrients – phosphates/nitratesAlgal bloom / oxygen depletion
141 Water Analysis Atomic Absorption Spectrometry used to detect heavy metals like Cd, Hg, PbpH metercolorimetry(Hach test Chlorine in pool water)
142 Electrolysisis the use of electricity to bring about a chemical reaction.KI/ Acidified water/ Na2SO4/CuSO4 / ions
143 Electrolyteis a substance that conducts electricity as a result of the presence of ions.
144 Electroplatingis the process where electrolysis is used to put a layer of one metal on the surface of another.
145 Electrochemical Series is a list of the elements in order of their standard electrode potentials.
146 Organic Chemistry is the study of compounds of carbon… (except some simple compoundslike CO2, CO and carbonates)
147 Hydrocarbon is a compound that contains only carbon and hydrogen includesalkanes, alkenes, alkynesexcludesalcohols, aldehydes, ketones, carboxylic acids, esters
148 Saturated compound is one with only carbon – carbon single bonds alkanes
149 Unsaturated compound is one which contains at least one carbon – carbon double or triple bondand undergoes addition reactionsalkenes / alkynestest for unsaturationdecolourise bromine solutionExam Q (Hons)08/Q9
150 Homologous Seriesis a series of chemical compounds of uniform chemical typeshowing gradations in physical propertieshaving a general formula for its memberseach member has similar method of prep. andeach member differs by (CH2) from previous member
151 Structural isomers are compounds with the same molecular formula but different structural formulas.e.g. butane and methyl propane are both C4H10need to know isomers up to C5H12
152 Aliphatican aliphatic compound is an organic compound that consists ofstraight (open) chains of carbon atomsand closed chain compounds with similar properties.
153 AromaticAn aromatic compound is an organic compound that contains a benzene ring structure in their molecules.(benzene – delocalised double bond)(disc. by Michael Faraday )(structure by Kekule)
154 Octane Numberof a fuel is a measure of the tendency of the fuel to resist knocking.(Best fuels = high octane number= 100 = 2,2,4 tri methyl pentane ) (Short chains, more branched chains, ring structures)(Worst fuels = low octane number=0 = heptane)Exam Q (Hons)‘08/Q6’06/Q6
155 Ways to increase octane number isomerisationcatalytic crackingdehydro-cyclis-ation (re-forming)add oxygenates
156 Isomerisationchanging straight chain alkanes into branched chain alkanes
157 Catalytic cracking is the breaking down of long chain hydro- carbon molecules into short chain molecules by heat and catalysts(for which there is a greater demand)Exam Q (Hons)‘07/Q6
158 Dehydrocyclisation ( Re-forming) involves the use of catalysts to form ring structuresstraight chain alkanes changed to cycloalkanescycloalkanes changed to aromatic compoundspetrol contains benzene = carcinogenhealth concerns
159 Adding Oxygenates addition of to petrol to increase the octane number. methanolethanolMTBEto petrol to increase the octane number.(Methyl Tertiary Butyl Ether or2 methoxy 2 methyl propane)
160 Exothermic reaction is one which produces heat. ∆H is minus ( giving away)
161 Endothermic reaction is one which takes in heat. ∆H is positive (add in)ammonium nitrate dissolving in water
162 Heat of Reactionis the heat change involved when the numbers of moles of reactants indicated in the balanced equation for the reaction react completely.
163 Heat of Combustion is the heat change involved when one mole of a substance iscompletely burned inexcess oxygen
164 Kilogram Calorific Value of a fuel is the heat energy produced when 1 kg of a fuel is completely burned in oxygen.
165 Bond Energyis the energy required to break one mole of covalent bonds and to separate the neutral atoms completely from each other.
166 Heat of Neutralisation is the heat change involved whenone mole of H+ ions from an acidreacts withone mole of OH- from a baseforming one mole of H2O
167 Heat liberated Heat liberated = M x C x Rise in temp. Kg kelvinM=Mass of solution in Kgc=specific heat capacityrise in temp in Kelvin
168 Heat of formation of a compound is the heat change involved when one mole of a compoundin its standard stateis formed from its elementsin their standard states.
169 Hess’s Lawstates that if a chemical reaction takes place in a number of stages,the sum of the heat changes in the separate stages is equal to the heat change if the reaction is carried out in one stage.(overall heat change is independent of the pathway)
170 Law of Conservation of Energy states thatenergy cannot be created or destroyedbutcan be changed from one form of energy to another.
171 Functional Groupis an atom or group of atoms which is responsible for the characteristic properties of a series of organic compounds.
172 Substitution Reaction is a chemical reaction in which an atom or group of atoms in a molecule is replaced by another atom or group of atomsmechanism = free radical substitutioninitiation (homolytic fission)propagationtermination
173 Addition Reactionis a chemical reaction is which two substances react together forming a single substance.Mechanism = Ionic additionApproach/ polarisation / heterolytic fission /carbonium ion / product formationonly happens to unsaturated compounds
174 Polymersare long chain molecules made by joining together many small molecules called monomers.
175 Elimination reactionis one in which a small molecule is removed from a larger molecule to leave a double bond in the larger molecule.
176 Organic Synthesisis the process of making organic compounds from simpler starting materials.
177 Chromatography is a separation technique in which a mobile phase carrying a mixturemoves in contact witha selectively adsorbent stationary phase.
178 Instrumentation Mass Spec. AAS GC HPLC IR spec. UV spec. X ray crystallography (option 2)
179 Mass Spec. Positively charged ions are separated PrinciplesProcessesPositively charged ions are separatedaccording to different relative masseswhen moving through magnetic fieldVapourisationIonisationAccelerationSeparationDetectionUsed toAnalyse blood of race horses for drugsIdentify substancesVictorA+
180 Atomic Absorption Spectrometry PrinciplesProcessesGround state atoms of an element absorb light characteristic of that element.Absorption is directly proportional to concentration.(higher absorbance means higher concentration of THAT ELEMENT present)DissolveAtomiseAbsorbMeasureDetectionUsed toanalyse water samples for heavy metals Cd Hg Pb
181 Gas Chromatography GCPrinciplesProcessesDifferent components have different tendencies to dissolve in a non-volatile liquid, which is coated on fine particles of a solid in a the GC columnInjection …Transport …Separation …Detection ...Used with MS in drug testingalso blood alcohol levelsmobile phase ?stationary phase??
182 HPLCPrinciplesProcessesHigh Performance Liquid ChromatographyDifferent components of a mixture have different tendencies to adsorb onto fine particles of solid in HPLC columnInjection …Transport …Separation …Detection …Used to separate less volatile mixtures e.g. growth promoters in meat.mobile phase ?stationary phase??
183 IR Infra red spectrometry PrinciplesProcessesInfra red spectrometryMolecules of a substance absorb infra –red of different frequencies.(different number/ type bonds)The combination of frequencies absorbed is unique to the molecules of each substancePrepare …Transmit IRAbsorption…Detection…Spectrum obtainedUsed to identify functional groupsand identify drugs
184 UV Ultra violet spectrometry Molecules absorb UV radiation PrinciplesProcessesUltra violet spectrometryMolecules absorb UV radiationElectrons promoted from ground state to higher energy states.Absorption is directly proportional to concentration.PrepareTransmit UV throughBlank (o%abs)Sample(known + unknown)Spectrum obtainedQuantatativeused to find amount of org. subs. e.g. drugs
185 X ray crystallographyProcessesPrinciplesWavelengths of Xrays are comparable to distance between atoms in a crystalXrays are scattered when they hit a crystal surfacePattern detected is analysed and structure worked outPrepare ….Transmit : x-ray detected on filmPattern analysed and structure worked outUsed to determine structure of macro-molecules e.g. DNA