The Dronfield SchoolSalters AS ChemistrySummer RevisionBy M Thomson

The first step to knowledge..Is knowing what you know..and what you dont know

Classifying your Knowledge..Things you can do

Things you can do already and dont need much more help withThings you could do

Things you understand but need to learn a little moreThings you cant do

Even with the answer in front you you, you cant do itYou now know everything!!

Even the longest journey...must start with a single step..we have about 50 steps

Navigation PageSelect the Unit you wish to studyMinerals to ElementsPolymer RevolutionAtmosphereEnd Slides

Questions on Elements from the Sea

a. Concentration CalculationsCan you answer these questions If you dissolve 1.00g of NaOH into 250cm3 of solution, what is its molarity?How many moles are there in 15cm3 of 0.2M solution?

1g = 1/40 = 0.025 moles in 250 = 0.1 Moles in 1000 ie 0.1M

No of moles = volume x molarity / 1000 = 15 x 0.2/1000 = 0.003

a. Ionic EquationsCan you answer these questionsWrite ionic equations for Silver with halide ionsAcid with alkali

Ag+(aq) + Cl- (aq) AgCl(s)

H+(aq)+ OH-(aq) H2O(l)

b. TitrationsCan you answer these questionsCan you give the details for doing a titrationIf 25cm3 of sodium hydroxide are neutralised by 15cm3 of 0.15M sulphuric AcidM Moles of H2SO4 = 15 x 0.15/1000 = 0.00225E Equation H2SO4 + 2NaOH Na2SO4 + 2H2OM 0.00225 0.0045 moles of NaOH in 25cm3O Molarity of NaOH = 0.0045 x 1000/25 = 0.18M (Sig Fig)

c. Electron Sub levelsCan you answer these questions What are the sublevels found in each electron shell, how many electrons can each sub level hold?

S holds 2, p holds 6, d holds 10Order 1s 2s 2p 3s 3p 4s 3d 4pEg Br is 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p5Dont forget the exceptionsCu 4s1 3d10 Cr 4s1 3d5 and remove 4s before 3d

d. Writing Electron ConfigurationsCan you answer these questionsCan you write down the electron configurations of FeFe2+CrCu

1s2 2s2 2p6 3s2 3p6 4s2 3d6

1s2 2s2 2p6 3s2 3p6 4s0 3d6

1s2 2s2 2p6 3s2 3p6 4s1 3d5

1s2 2s2 2p6 3s2 3p6 4s1 3d10

e. Shapes of MoleculesCan you answer these questionsDraw a dot cross diagram for NH3Describe the shape and bond angle of the moleculeH H HXo xo xo N xx

Shape Trigonal pyramidBond angle 107o

f. Polar Covalent BondsCan you answer these questionsWhat causes a bond to be permanently polarWhich is more polar C-Cl C-Br or C-I

Difference between electronegativity between the atoms, one nucleus attracts the electron pair more than the otherThe C-Cl bond is the most polar

g. Intermolecular BondsCan you answer these questions What sort of intermolecular bonds are there between bromine moleculesWhat sort of intermolecular bonds occur between HBr moleculesBr2 Instantaneous dipole induced dipole bondsHBr Permanent dipole bonds

h. Sodium ChlorideCan you answer these questionsDraw a 3 dimensional structure of sodium chloride

i. Oxidation StatesCan you answer these questionsWhat is the definition of Oxidation StateWhat is the oxidation state of Iodine in KIO3

The number of electrons lost by an atom when forming a compound or ion

K+ O2- O2- O2- so its I +5 NB not 5+

i. Oxidation and ReductionCan you answer these questionsIn the equation below, can you assign oxidation states to each element and say what is being oxidised and what is reduced 2H2S + SO2 2H2O + 3S

+1 -2 +4 -2 +1 -2 0 Oxidised Reduced

j. Half and full equationsCan you answer these questionsCan you write half equations for: SO2 H2SO4Can you write a half equation for MnO4- Mn 2+ Can you combine them into a full equation

SO2 + 2H2O H2SO4 + 2H+ + 2e-MnO4- + 8H+ + 5e- Mn2+ + 4H2OX5X25SO2 + 10H2O + 2MnO4- + 16H+ + 10e- 5H2SO4 + 10H+ + 10e- + 2Mn2+ + 8H2O

k. The Blocks of the Periodic TableCan you answer these questions Can you label the blocks of the periodic table?

sdpf

l. Ionisation EnthalpiesCan you answer these questionsWrite en expression for the 1st and 2nd ionisation enthalpies of MgExplain why the 2ns IE for Mg is higher than the 1st and the 3rd is much higherMg(g) Mg+(g) + e-Mg+(g) Mg2+(g) + e-Successive IEs are always larger as you are removing an electron from an increasingly positively charged ionThe 3rd IE of Mg is much higher as you are breaking into a new shell which is closer to the nucleus and held more strongly

m. Properties of HalogensCan you answer these questionsCan you describe the appearance of Cl, Br and IWhat happens to their B.PsHow does their solubility in water and hexane change

Yellow gas, red/brown liquid, black solidBoiling points increase down groupSolubility decreases down group..more soluble in hexane

n. Manufacturing ChemicalsCompare the following Industrial reactionsThe Haber Process making AmmoniaFermentation of sugar to make alcoholHaber Process Continuous needs high temperaturesFermentation: Batch process, works at 40oC

o. Halogens Reacting with HalidesCan you answer these questionsWhats the difference between halogen and halideCan you complete these equationsKBr + Cl2 KBr + I2

2KCl + Br2 No reaction

o. Reactivity of the HalogensCan you answer these questionsWhat happens to the reactivity as you go F-Cl-Br-ICan you explain this trend

Reactivity decreases down group

As atoms get larger, they attract electrons less strongly and form weaker covalent bonds

p. Silver HalidesCan you answer these questionsCan you write equations for sodium chloride, bromide and iodide reacting with silver nitrateCan you write them as ionic equationsCan you give the observations for each reaction

AgNO3(aq) + NaX(aq) AgX(s) + NaNO3(aq) Ag+(aq) + X-(aq) AgX(s) AgCl White precipitate, AgBr cream , AgI pale yellow

q. Health and Safety IssuesCan you answer these questionsCan you give the hazard symbols for corrosive, toxic, flammable , oxidising and harmfulCan you state the safety precautions of each hazard

Sensible answers involving protective clothing, goggles, breathing apparatus etc

r. Uses of Chlorine and BromineCan you answer these questionsCan you give 2 uses of bromineCan you give 2 uses of Chlorine

Bromine Flame retardents, pesticides, in oil recovery from wellsSterilising water, making PVC etc

s/t. Naming HalogenoalkanesCan you answer these questionsCan you name this compound H Cl Cl Br H H H C C C C C C H H Cl H H H H 4-Bromo-2,2,3-trichloro hexane

u. Making a HalogenoalkaneCan you answer these questionsHow can you make 1-chloropropane from propan-1-ol?

React it with concentrated HCl

v. Purifying an Organic LiquidCan you answer these questionsThe 1-chloropropane prepared in the previous slide is impure, state two steps in purifying it

Shake with water to remove water soluble impurities then distil it

w. Halogenoalkane propertiesWhat are the trends in the properties of Chlorobutane, bromobutane and IodobutaneBoiling pointsFormation of radicals with UV lightReaction with water, ammonia and hydroxide

Boiling points increase down groupThey form radicals more easily down group (weaker bond)They get more reactive down group

x. Nucleophilic SubstitutionCan you answer these questionsWhat is meant by hydrolysis?What is meant by substitution?What is a nucleophile, give an exampleWhat is a carbocation, draw the structure of one

Splitting of a molecule with waterWhen one group swaps with anotherNucleus lover something with some negative chargeA Carbon atom with 3 bonds and a positive charge

y. Nucleophilic SubstitutionCan you answer these questionsWrite a mechanism for the reaction between sodium hydroxide and bromomethaneWhat is the product if ammonia is used instead?

Forms an amine -NH2

z. Reactivity of HalogenoalkanesCan you answer these questionsWhich is more polar C-Cl C-Br or C-IWhich bond is stronger C-Cl C-Br or C-IWhich is more reactive, the chloro, bromo or iodo compound?

C-Cl C-Cl

C-I as the bond is weakest

aa. Shapes of MoleculesCan you answer these questions Show the bond angles in the molecule of ethanol105o109o109o

end. Extracting Bromine Can you answer these questionsIn the flow diagram below, can you say what is happening to the Bromine in each step: Cl2 SO2 Cl2NaBr >>>>>>> Br2 >>>>>>> HBr >>>>>>>> Br2

Oxidation Reduction Oxidation

Aa. Giant Covalent StructuresCan you answer these questionsCan you draw the structures of diamond, graphite and SiO2DiamondGraphiteSilicon Dioxide

A a. Carbon and Silicon DioxidesCan you answer these questionsCan you draw the structures of CO2 and SiO2 and explain why they have different propertiesCO2 Simple molecule with double bonds and weak attraction between moleculesSiO2 Macromolecule strong single bonds between all the atoms

end. Hydrated IonsCan you answer these questionsWhy is water such a good solvent for ionic substancesDraw a hydrated ion of Na+ and Cl-

Because water is a permanently polar molecule

end. Problems with Mineral ExtractionCan you answer these questionsCan you name 3 environmentally problematic byproducts from metal extraction and the problems they cause

Waste material separated during purificationSulphur dioxide acid rainCarbon monoxide toxic to humansCarbon dioxide.greenhouse gas

end. Vacuum FiltrationCan you answer these questionsCan you draw the apparatus for vacuum filtration

Buchner Funnel

end. Acid-Base ReactionsCan you answer these questionsWhich is the acid and which the base in the reaction below:NH3 + H2O NH4+ + OH-

Base..accepts ProtonAcidDonates Proton

End Flow DiagramsCan you answer these questionsCan you draw a flow diagram for making bread

Mix Flour water and yeastKnead into a DoughLeave somewhere warm to riseKnead and place in tin, leave to riseBake in Hot ovenENJOY!

end. Types of ReactionCan you answer these questionsCan you classify each of these reactionsNaOH + HCl NaCl + H2O

NaCl + AgNO3 AgCl + NaNO3

CuSO4 + Fe Cu + FeSO4

Neutralisation

Precipitation

Redox

end. Extracting MetalsCan you answer these questionsWhat are the 3 major steps in extracting a metal from its ore

Extract and purify the metal oreReduce the metal ore to the metalPurify the metal

end. Acid Base ReactionsCan you answer these questionsWhat is the definition of an Acid?What is the definition of a Base?

Acid = Proton Donor

Base = Proton Acceptor

Navigation PageSelect the Unit you wish to studyElements from the SeaPolymer RevolutionAtmosphereEnd Slides

Questions on Polymer Revolution

a. WaterCan you answer these questionsCan you show the bonding and shape of waterCan you show the attraction between water molecules

b. Intermolecular AttractionsWhat forms of attraction are there between molecules ofBromineHBrH2OExplain their BP

Instantaneous Dipole/Induced DipolePermanent dipole/permanent dipoleHydrogen Bonding Hydrogen bonding is strongest

c. Dissolving PolymersCan you answer these questionsDissolving polymers have OH groups, why does this make them soluble?If there are too many OH groups the polymer becomes insoluble why is this?

OH Groups can hydrogen bond with waterIf there are too many OH groups, they will hydrogen bond with each other making the polymer insoluble

d. Naming AlkenesHex-3-ene

e. Recognising Functional GroupsWhat functional groups are represented byC2H5OHC6H5OHCH3CHOCH3COCH3CH3COOHAlcoholPhenolAldehydeKetoneCarboxylic Acid

f. Types of AlcoholCan you answer these questionsDraw 3 different types of alcohol with the formula C4H10O

Primary Secondary Tertiary

g. Heating Under RefluxCan you describe the technique for heating under reflux

h. Elimination ReactionCan you answer these questionsWrite an equation for the reaction of butan-2-ol with concentrated sulphuric acidWhat type of reaction is thisWhy can two different products form

CH3CH2CH(OH)CH3 CH3CH2CH=CH2 + H2OEliminationCan form but-1-ene or but-2-ene

i. Addition PolymerisationCan you answer these questionsWhat are the product(s) of additional PolymerisationWhat type of monomer produced an addition polymer

Addition polymerisation produces only a polymer,, no coproductAddition polymers come from alkene monomers

i. Monomers and Polymers

j. Reactions of AlkenesWrite equations for the reaction of ethene withBromineHBrHydrogen (Name catalyst)Water(Name catalyst)

C2H4 + Br2 CH2BrCH2Br C2H4 + HBr CH3CH2Br C2H4 + H2 C2H6 C2H4 + H2O CH3CH2OHNickelConcentrated sulphuric acid

k. Alcohol ReactionsHow will ethanol and phenol behave when added to

Acidified Potassium Dichromate(VI)Concentrated sulphuric acid

Ethanol oxidises Ethanol dehydrates

l. Additions and ElectrophilesCan you answer these questionsWhat is an addition reactionWhat is an electrophile, give an example

A + B C

Electron lover something with some positive chargeEg + H-Br -

l. Electrophilic AdditionWrite a mechanism for the reaction between Bromine and EtheneWhat type of mechanism is this?CarbocationElectrophilic Addition

m. Alkene structuresCan you answer these questionsCan you draw 5 structures with the formula C4H8

Trans and cis but-2-ene But-1-ene Methylpropene Cyclobutane

m. Cis and Trans (Z/E) AlkenesCan you answer these questionsCan you say what type of isomerism this isWhy are the two forms differentWhich form is more stable and why

Geometric IsomerismThe double bond cant rotateThe trans(E) form is more stable, methyl groups farther apart

n. Attractions Between PolymersCan you state the intermolecular attractions between the chains inPolyethenePolychloroethene(PVC)Polyhydroxyethene

Instantaneous Dipole/Induced Dipole

Permanent dipole/permanent dipole

Hydrogen Bonding

o. Thermo and Thermosetting PlasticsCan you answer these questionsWhat is the difference between a thermoplastic and a thermosetting plastic

Thermoplastics can be melted because there is only weak attraction between the chain moleculesThermosetting polymers will not melt because there are covalent bonds cross linking the molecules

p. Infra red SpectraCan you Identify the key peaks in the infra red spectrum of CH3COOH

q. The Fingerprint RegionCan you Identify the fingerprint region in the spectrum and say what it is used forFingerprint region: Used for comparisons

end. Accidental DiscoveriesCan you answer these questionsWhy were the structures of early polymers irregular and how were they improved

The polymerisation with an oxygen catalyst was a free radical mechanism giving branched chains which do not pack together closely, the use of better catalysts gave more regular structures

end.History of Addition PolymersCan you answer these questionsCan you describe the discovery of polyetheneCan you explain how regular polymer structures and conducting polymers were made

Made by accident when air (catalyst) leaked into ethene which was then compressed and polymerisedZiegler-Natta Calaylsts (Titanium chloride) allow regular polymer structuresConducting polymers were found to emit light

end. Polar MoleculesCan you answer these questionsWhich of these molecules is/are polar H2O NH3 CH4

Polar Polar Non Polar

end. Structure and PropertiesWhat effect will each of the following have on the properties of a polymerMaking the chains longerHaving side groups on the chainsHaving branched chainsMaking chains more flexibleCross linking chainsMaking structure more regular

Stronger higher MPLess flexibleLess denseElasticThermosettingMuch Stronger

end. CrystallinityCan you answer these questionsWhat is meant by a crystalline area of a polymerWhat effect does crystallinity have on properties

A crystalline area is where the chains are regularly packed, There is stronger attraction here

Navigation PageSelect the Unit you wish to studyElements from the SeaPolymer RevolutionAtmosphereEnd Slides

Good Evening, Welcome to the Dronfield SchoolPlease wait for this page to load fully before ProceedingENTER

Questions on Atmosphere

a. Carbon and Silicon DioxidesCan you answer these questionsCan you draw the structures of CO2 and SiO2 and explain why they have different propertiesCO2 Simple molecule with double bonds and weak attraction between moleculesSiO2 Macromolecule strong single bonds between all the atoms

b. Rates of ReactionCan you answer these questionsWhat has to happen for a chemical reaction to take place?State 4 things that can sped up a chemical reaction

Molecules must collide with sufficient energyIncrease surface area, temperature, concentration or catalyst

c. Energy ProfilesCan you answer these questionsDraw an energy profile for an endothermic and an exothermic reaction.On the profiles, label the activation energy

d. Temperature and reaction RateCan you answer these questionsSketch a graph showing the way temperature affects reaction rateExplain the shape of the graph you have drawn

Increasing the temperature dramatically increases the number of particles with sufficient energy (activation energy) to react

e. CatalystsCan you answer these questionsHow does a catalyst speed up a chemical reaction?Show this on the reaction profile

By Providing a reaction pathway needing less activation energy

f. Intermediates in CatalysisCan you explain and illustrate the role of intermediated in Homogeneous catalysisIn the Reaction A+ B products if the Catalyst is C then The reaction is A _ C AC then AC +_ B Product + CAC is the intermediate, it is the small dip in the catalised reaction profileIntermediate

g. Dynamic EquilibriumIf a reaction is in Dynamic EquilibiumWhat is meant by the term dynamic?What is meant by the term equilibrium?

Dynamic, means continually going onEquilibrium means the reaction is going forwards and backwards at the same rate so there is no net change in concentration

h. Carbon Dioxide and WaterCan you answer these questionsWrite an equation for carbon dioxide dissolving in waterWrite an equation for carbon dioxide reacting with water

CO2(g) CO2 (aq)

CO2 (aq) + H2O (l) H+ (aq) + HCO3- (aq)

h.Le Chateliers PrincipleFor the Exothermic Reaction N2(g) + 3H2(g) 2NH3(g)Describe and explain the effects on the equilibrium ofIncreasing the concentration of the nitrogenIncreasing the temperatureIncreasing the pressure

Moves equilibrium to right to lower [N2]Moves equilibrium to left (to lower temperature of exothermic reaction)Move equilibrium to right to lower pressure 4 mols of gas go to 3 mols

i. Composition of the AtmosphereCan you answer these questionsWhat the the three major gases in the atmosphereName three gases found naturally in trace amountsName three pollutant gases

Nitrogen Oxygen ArgonCarbon Dioxide Krypton NeonSulphur dioxide Nitrogen dioxide Methane

j. ppmCan you answer these questionsCarbon dioxide makes up 0.037% of the atmosphere, what is this in Parts per million?

To turn % to ppm, multiply by 10000

0.037 x 10000 = 370ppm

k. OzoneCan you answer these questionsWhat is the structure of an ozone moleculeHow is ozone formed in the atmosphere?How is ozone naturally destroyed in the atmosphere?

Formation O2 O* + O* O* + O2 O3

Destruction O3 O* + O2 O* + O* O2

l. Understanding Ozone DepletionCan you explain how and where depletion of the ozone was first noticed and what it was attributed toThe ozone depletion was notices near the north and south poled by measuring infra red absorption of the bond in ozone. It was immediately accepted that it was caused by chlorine radicals from CFCs

m. Homolytic and Heterolytic FissionCan you answer these questionsWhat happens in heterolytic bond fission?What happens in homolytic bond fission?What can cause homolytic fission?

Both electrons go to one atomOne electron goes to each atomUV light or very high temperatures

n. Steps in a Radical ReactionCan you answer these questionsWhat is the first step which forms the radicals called?What name is given to the steps which spread the chain reaction?What name is given to steps where 2 radicals join?

Initiation

Propagation

Termination

o. Alkanes reacting with HalogensCan you answer these questionsGive an overall equation for methane reacting with bromineState the reaction conditions and name the mechanismGive the 4 steps of the reaction naming each stepExplain why C2H6 and CH2Br2 form as byproducts

Br2 2Br* Br* + CH4 CH3* + HBrCH3* + Br2 CH3Br + Br* Br* + Br* Br2 CH4 + Br2 CH3Br + HBr Free Radical Substitution (UV light)CH3* + CH3* C2H6 CH3Br + Br* CH2Br* + HBr

p. CFCsCan you answer these questionsGive 3 uses of CFCsWhat 2 properties made them so useful?

Aerosols, fridges and solvents

Unreactive and very volatile

p.Replacing CFCsCFCs can be replaced by HCFCs, HFCs or alkanesExplain what these three compounds areGive an advantage of each oneGive a disadvantage of each one

Hydrochloroflurocarbon Hydrofluorocarbon Hydrocarbon None is ozone depletingExpensive Expensive Flammable

q. Protection by OzoneCan you answer these questionsHow does the ozone layer protect us?

By absorbing UV light (in the process ozone is destroyed, but more is formed)

q. Depletion of the Ozone LayerCan you answer these questionsHow do CFCs cause ozone depletion?

CFCs form Cl* radicals in the stratosphereCl* + O3 ClO + O2ClO + O Cl* + O2

r. Missing the Ozone HoleWhy did the Americans at first miss the evidence for the hole in the ozone LayerThey used satellites to measure the ozone concentrationsBut they programmed the computers to reject any unusual results

s. Quantised EnergyCan you answer these questionsWhat is a quantum of energy?What forms of energy in a molecule are quantised?

A quantum, is the smallest allowed amount of energy a particle can haveElectron energy levels, vibrations and rotations are all quantised

t. Energy and MoleculesCan you answer these questionsWhat effect does microwave radiation have on molecules?What effect does Infra red radiation have on bonds?What effect does ultra violet radiation have on bonds?

Makes molecules rotate and heat up

Makes bonds vibrate

Makes bonds break

u. Frequency and Energy of RadiationCan you answer these questionsWhat is the link between the energy of radiation and its frequency?

E = hf

v. Homogeneous CatalysisCan you answer these questionsWhat two steps are needed for a homogeneous catalyst to speed up a chemical reaction?

Catalyst joins to chemical forming an intermediateCatalyst breaks off so it can react again

v. Greenhouse EffectCan you answer these questionsExplain the causes of the greenhouse effectWhat are some of the consequences of the greenhouse effect?

Visible and ultra violet light passes through the atmosphere and is re-emitted as infra red radiation.Carbon dioxide molecules absorb infra red radiation and prevent it escaping back into space.Global warming, rise in sea levels, climate change

w.Greenhouse Gases and Global WarmingWhat is the link between changes in Carbon dioxide levels in the atmosphere and global temperaturesCarbon dioxide levels are increasing, global temperature levels are rising, the two are probably linked with the CO2 level rise causing the temperature rise

x. Controlling Global Warming

Can you answer these questionsWhat steps can be taken to reduce carbon dioxide build-up?

Burn less fossil fuelReplace trees that have been chopped down or increase photosynthesis in the seasCapture the CO2, solidify and store under the oceans

end. RadicalsCan you answer these questionsHow are radicals formed?What conditions are neededWhat are radicals like?How do radicals react?

Homolytic FissionUV light, high tempHave odd electronsChain reactions with the first thing they hit

end. HalogenoalkanesCan you answer these questionsDraw two structures of halogenoalkanes with 3 carbons and a bromine atom

CH3CH2CH2Br CH3CHBrCH3

end. Effects of RadiationCan you answer these questionsGiven these data, predict whether you can get a sun tan under water and behind glass:Frequency of UV Radiation: 8-11 x 1014 HzWater Absorbs above 16 x 1014Glass absorbs above 9 x 1014

Glass absorbs UV but water does not

Navigation PageSelect the Unit you wish to studyElements from the SeaPolymer RevolutionAtmosphereEnd Slides

Good Evening, Welcome to the Dronfield SchoolPlease wait for this page to load fully before ProceedingENTER

The EndGood luck with the exam