Paper 2 Flashcards

Question

What is a nucleophile

Answer 1

Lone pair donor, forms covalent bond with δ+ atom in another molecule

Answer 2

Hydroxide ion acts as nucleophile Heat under reflux and aqueous R-BX + KOH -> R-OH + KX

Answer 3

Water acts as nucleophile R-X + H20 -> R-OH + H+ + X- Ag+ X -> AgX ethanol !! 60 degrees

Answer 4

Reflux, aq and ethanol R-X + KCN -> R-CN +KX

Answer 5

R-X + 2NH3 -> R-NH2 + NH4X Conc ammonia at room temp Or heat in sealed tube Heat in sealed tube so that it reacts fast but ammonia liberated if it was under reflux, ammonia gas would not be condensed by the reflux condenser

Answer 6

R-Br + KOH -> alkene Of chain length R + H20 + KX Hydroxide ion acts as a base Heat under reflux with ethanol conc KOH

Answer 7

Equal amount of the halogenoalkanes are placed in a test tube water bath 60 degrees ethanol and silver nitrate and time how long it takes the ppt to appear Tertiary fastest secondary then primary SN1 faster than SN2 Iodo after than bromo faster than chloro because C-I bond enthalpy is the weakest, then bromo then chloro

Answer 8

Lone pair on OH arrow from that to δ+ carbon, δ- on Br - attacks from opposite side of bromine arrow from C-Br bond to Br -> Forms intermediate with five bonds, square bracket and Br and OH bonds dotted lines, remember charge on intermediate, -> final product and Br-

Answer 9

Lone pair on ammonia, dipole on c-Cl Lone pair on ammonia arrow to carbon, then arrow from C-Cl bond to Cl Intermediate with five bonds around carbon and four around ammonia Then forms 3HN-C-RHH + Cl- ammonia has a positive charge Another ammonia lone pair arrow attacks hydrogen, arrow from H-N bond to N Forms NH4Cl + 2HN-CRHH

Answer 10

Dry alcohol solid PCl5 R-OH + PCl5 -> R-Cl + POCl3 + HCl This is the test for alcohol as steamy fumes of HCl is given off

Answer 11

50% conc H2SO4 to prevent HBr being oxidised, heat under reflux KBr + H2SO4 -> KHSO4 + HBr R-OH + HBr -> R-Br + H20

Answer 12

Warm, moist red phosphorous 2P + 3I2 -> 2PI3 3R-OH + PI3 -> 3R-I + H3PO3

Answer 13

Dilute sulphuric acid R-OH + [O] -> R=O + H20 distill as produced (hot ethanol 60 degrees) R-OH + 2[O] -> R-OOH + H20 heat under reflux Secondary -> just to ketone - can be refluxed HUF, electric heater, then use test for aldehyde to determine if it was primary or secondary secondary Dichromate orange to green

Answer 14

Warm, conc H3PO4 Alcohol -> alkene + H2O (Or heat over aluminium oxide - separate reaction)

Answer 15

Volatile/ flammable / toxic substancesthe •Place in round bottomed flask with vertical reflux condenser •Water in at bottom and out at top •top of reflux condenser being open •use electric heater No I reacted reagent escapes Add antibumping granules Distill off wanted product at bp

Answer 16

``` Sparingly soluable organic product •shake reaction mixture in separating funnel with solvent eg ethanol, cyclohexane, Dry ether. Depends on circumstance •organic layer collected only •wash and dry organic layer •still off solvent ``` Suitable solvent dissolves the organic and is low boiling point so can be easily removed

Answer 17

* Place a small about of a test liquid in an ignition tube and attach to thermometer with rubber band. * Place in beaker with water. Clamp thermometer * Place empty capillary tube in liquid, open end below surface * Heat water and stir, slowly heat until rapid stream of bubbles comes out. Note temp and stop heating * allow to cool, stir until bubbles stop and liquid sucked into capillary tube. Note temp

Answer 18

Use an anhydrous salt such as calcium chloride to remove any water from a crystal product. Anhydrous sodium sulphate or calcium chloride Initial mixture is cloudy, clear when dry. Then filter organic liquid

Answer 19

Optical isomerism is a result of chirality in molecules with a single chiral centre. This results in optical isomerism. Where the optical isomers are object and non superimposable mirror images

Answer 20

The ability of a single optical isomer to rotate the plane of polarisation of the plane-polarised monochromatic light in molecules containing a single chiral centre

Answer 21

A solution containing equimolar amounts of the two enantiomers does not rotate the plane of plane polarised light

Answer 22

SN1 - chance of attack is identical from top or bottom - racemic mix. The carbocation has three pairs of bonding electrons and no lone pairs, so it’s shape is triangular planar around the positive carbon atom SN2 - nucleophile attacks from the opposite side to the halogen therefore single optical isomer

Answer 23

Lower than alcohols because does not hydrogen bond intermolecular

Answer 24

Solvable as can hydrogen bond with water | They cannot hydrogen bond with themselves

Answer 25

Copper sulphate and potassium tartrate Deep blue solution Aldehydes only -> deep blue solution forms red ppt of Cu2O copper (I) oxide Aldehyde oxidised R=O + [O] + OH- -> ROO- +H20 Salt of carboxlyic acid Test for aldehyde

Answer 26

Sodium hydroxide and silver nitrate dissolved in dilute ammonia, warm Only aldehyde Silver mirror produced R=O + [O] + OH- -> ROO- +H20 Ag(NH3)2^+ -> Ag + 2NH3

Answer 27

R=O + [O] + OH- -> ROO- +H20 Aldehyde only Orange reduced to green (If it was manganate (VII) purple to colourless in acidic or brown ppt in alkaline)

Answer 28

In dry ether Aldehyde -> primary alcohol Ketone -> secondary R=O + 2[H] -> R-OH R1-CO-R2 + 2[H] -> R-CHOH-R2 Also works with hydrogen with a platinum catalyst Does not reduce double bonds (hydrogen with platinum catalyst does)

Answer 29

In the presence of HCN pH 8 R=O + HCN -> ROHCN Excess potassium cyanide and some dilute sulfuric acid or hydrogen cyanide and some sodium hydroxide pH allows enough of CN- and HCN

Answer 30

Dipole on C=O lone pair on CN- from the KCN but as ion Arrow from CN lone pair to carbon, arrow from double bond to oxygen CRHCNO- Lone pair on negative oxygen attacks hydrogen on HCN molecule, arrow from H-CN bond to the carbon Forms CRHCNOH and CN- If pH is too low not enough CN- if too high not enough HCN

Answer 31

Racemic minxture, planar around C=O group, equal chance of attack from left right of planar centre (Not the intermediate which is tetrahedral). The initial aldehyde is the planar one

Answer 32

Test for carbonyl group Brady’s reagent Orange ppt Filter off and recrystallise and do melting point determination to indentify compound Does not do carboxylic acids

Answer 33

Does ethanal, methyl ketones, ethanol also(gets oxidised first) and secondary methyl alcohols, gently warm with iodine and sodium hydroxide CH3COR + 3I2 + 4NaOH -> CHI3 + RCOO-Na+ + 3NaI + 3H2O Stepwise I2 + 2OH- -> IO- + I- + H2O CH3COR + IO- CI3COR IO withdrawing weakens σ bond with carbon -> CHI3 + RCOO- Pale yellow ppt of iodoform is produced

Answer 34

Higher as it can hydrogen bond

Answer 35

Soluble ad can hydrogen bond

Answer 36

•R-OH + 2[O] -> RCOOH + H2O •R=O + [O] -> RCOOH heat under reflux with acidified potassium dichromate primary alcohol RCN + H+ + 2H2O -> RCOOH + NH4+ Reflux with dilute acid Or hydrolysis of an Ester

Answer 37

RCOOH + 4[H] -> ROH + H20 Dry ether

Answer 38

RCOOH + NaOH -> H2O + RCOO-Na+

Answer 39

Solid, dry acid RCOOH + PCl5 -> ROCl + POCl3 + HCl

Answer 40

Acid catalyst conc H2SO4 RCOOH + R’OH reversible RCOOR’

Answer 41

RCOCl + H20 -> RCOOH + HCl Vigorous

Answer 42

RCOCl + R’OH -> RCOOR’ + HCl Not reversible and Cl is a better leaving group therefore better than wth carboxylic acid Dry

Answer 43

Conc ammonia, dry RCOCl + NH3 -> HCL + RONH2 HCl + NH3 -> NH4Cl

Answer 44

RCOCl + R’NH2 -> RCONHR’ + HCl Dry

Answer 45

Acid RCOOR’ + H20 ⇌ RCOOH + R’OH acid cat, low yield Alkali RCOOR’ + NaOH -> RCOO-Na+ + R’OH Goes to completion

Answer 46

Condensation - water is lost Acyl chloride then HCl lost Monomers join together with the elimination of a simple molecule such as water or hydrogen

Answer 47

Kekule model and delocalised model Overlap of p-orbitals to form π-bonds

Answer 48

•Enthalpy of hydrogenation : The predicted value is lower, more exothermic than the true value because benzene is stabilised because of the delocalisation of the π-electrons Predicted -357 real -207 KJmol^-1 •c-c bond lengths, C=C is slightly shorter than C-C in aliphatic compounds, x-ray diffraction shows that the bond lengths between the C atoms are the same •does not undergo the typical electrophilic addition reactions of unsaturated compounds

Answer 49

The π-bonds are delocalised in benzene and localised in π-bond of alkene The compound is more stable Substitution rather than addition

Answer 50

Iron catalyst 2Fe + 3Br2 -> 2FeBr3 FeBr3 + Br2 -> FeBr4- + Br+ Bromine liquid Dry conditions Heat under reflux Br substitutes onto ring for hydrogen Benzene + Br2 -> bromobenzene + HBr Or UV light - heat under reflux, addition occurs from free radicals

Answer 51

Sulphuric acid conc Of H2SO4 and HNO3 catalyst warm to 50degrees in flask with reflux condenser HNO3 + H2SO4 -> H2NO3^+ + HSO4- H2NO3^ -> NO2+ + H2O NO2 substitutes on ring H lost replaces in HSO4-

Answer 52

Alkylation Dry R-Cl + AlCl3 -> R+ + AlCl4- R+ substitutes on ring, H takes a Cl forming HCl and reforming the AlCl3 Acylation Dry Acyl chloride, anhydrous aluminium chloride R-OCl + AlCl3 -> R+=O + AlCl4-

Answer 53

Generate electrophile 1) Kekule •arrow from a double bond to the electrophile •intermediate has positive charge on the carbon next to the one the electrophile has attached too, arrow from the hydrogen carbon bond next to electrophile back to where double bond is reformed •double bond reformed •show catalyst regenerated by hydrogen 2) delocalised -> instead of coming from double bond, comes from Armstrong inner circle •gets circle turns into horseshoe open opposite where the electrophile has attached, positive charge inside horseshoe, •arrow from hydrogen bond carbon bond to positive charge in horse shoe •show solvent getting reformed

Answer 54

Lone pair in OH is delocalised in the π-system electron density is increased. More susceptible to electrophilic substitution Ortho and para directing Bromine water water works, no need for FeBr3 ROOM TEMP 3 substitutes instead of one (Same with nitration) C6H6OHBr3 + 3HBr White ppt

Answer 55

H2N-CHR-COOH

Answer 56

R-NH2 + H2O -> RNH3^+ + OH-

Answer 57

R-NH2 + HCl -> R-NH3^+Cl- Strong acid

Answer 58

R-NH2 + CH3COCl -> R-NH-COCH3 + HCl

Answer 59

Dropwise R-NH2 + R’Cl -> R-NH2-R’ pos charge on nitrogen and Cl- Excess R-NHR’R’ + HCl

Answer 60

Aliphatic - electron density pushes into nitro group - more available lone pair. More basic Ammonia Aromatic lone pair delocalised in the ring, less available lone pair , less basic

Answer 61

•halogenoalkane conc ammonia and aqueous ethanolic solution, long time in a sealed tube R-Cl + 2NH3 -> R-NH2 + NH4Cl •reduction of nitriles warm with LiAlH4 in dry ether, hydrolyse with dil acid R-CN + 4[H] -> R-NH2

Answer 62

Benzene plus nitric acid plus sulphuric acid forms benzene-no2 Then heat under reflux with conc HCl and Tin to reduce to benzene-NH2 Add excess NaOH Steam distill Then place in separating funnel and sodium chloride added to reduce solubility, the phenyl-amine later is run off and some solid anhydrous potassium carbonate is added to dry

Answer 63

•ethanoyl chloride + ammonia CH3COCl + NH3 -> CH3CONH2 + HCl

Answer 64

Condensation reaction Acyl chloride and amine HCl lost Amino acids - water lost

Answer 65

Zwitterions are formed (solid at room temp) The ammonia group is protonated, the carboxylic acid is deprotonated Therefore can act as an acid or base (Also strongly attracted)

Answer 66

Only one isomer is naturally occurring therefore it rotates the plane of plane polarised monochromatic light

Answer 67

•contain a peptide bond when amino acids combine, by condensation polymerisation. One hydrogen is lost on the NH2 group and the nitrogen bonds with a carbon from the carboxylic acid group Water is lost the same no of waters as no of monomers •can be hydrolysed to form the constituent amino acids, which can be separated by chromatography

Answer 68

•halogenoalkane + magnesium in dry ether with trace iodine R-I + Mg -> R-MgI Then with carbonyl compounds R-MgI + R’R’’CO -> R-CR’R”-OMgI (R is opposite O) Dil acid O-H of MgI Carbon dioxide R-MgI + CO2 -> RCOOMgI Dilute acid - RCOOH All in dry ether until it is hydrolysed with dilute acid (and water -hydrolysed)

Answer 69

* wash with sodium hydrogencarbonate in separating funnel, removes acidic impurities, release pressure CO2. Stop when no further gas produced * discard aq layer. Wash organic layer with water to remove unreacted sodium salts and soluable organic substances e.g ethanol * discard aqueous layer. Dry with anhydrous salt eg calcium chloride complete when goes clear from cloudy * distill and collect in range of 2 degrees either side of boiling point

Answer 70

* filter * dissolve ppt in minimum about of suitable solvent when solubility is high when hot and low when cold * filter hot solution again through fluted filter paper using warmed stemless funnel into conical flask-> removes insoluable impurities * cool solution * filter solvent + pure solid under reduced pressure in Buchner funnel * collect solid on filter paper, discard liquid- removes soluable impurities * wash solid, ice cold solvent and leave to drypp

Answer 71

* Insert solid into capillary tube and attach tube, open end up to thermometer with a rubber band * place thermometer into bath of liquid with higher bp than mp of solid * heat liquid bath, stir and note temp where solid melts * the smaller the range the purer the solid

Answer 72

* used to extract a volatile liquid that is immiscible with water from a Complex mixture, partially for a substance that would decompose at its boiling point or just for convenience of it boiling bellow it’s boiling point * heat water to form steam which enters a round bottomed flask with the substance and water. Then distill with a condenser * have a safety vent * electric heater

Answer 73

Relative heights relate to the relative numbers of hydrogens in each environment

Answer 74

If the proton of a hydrogen atom has n hydrogen atoms on neighbouring carbon atom, its peak will be split into (n+1) subpeaks

Answer 75

Separates components of a mixture between a mobile phase and a stationary phase The sample dissolved in a solvent and washed through a stationary phase by a mobile phase called an eluent The competition between the sample molecules adsorbed by the stationary phase and dissolved by the eluent results in separation depending on how soluable they are in eluent and less adsorbed by stationary phase as these move faster through apparatus

Answer 76

For a one way chromograph Rf=distance moved by substance/ distance moved by eluent

Answer 77

TLC - thin layer chromatography HPLC - high performance liquid chromatographs GC - gas chromatography Different substances have different retention times due to their strengths attractions with the mobile and stationary phase These can be used in conjunction with mass spectrometry (in applications such as forensics and sport)

Answer 78

Increase in concentration causes an increase in reaction rate. Collisions occur more frequently as more in the same volume Successful collisions also occur more frequently

Answer 79

Molecules have higher KE large fraction possess activation energy greater the activation energy, larger proportion of collisions result in reaction. Also a increase in collision frequency

Answer 80

Increases no of moles per cm^3 -> frequency of collisions increased KE sameX frequency of successful collisions increases. Therefore rate increases However if the reaction is gaseous catalysed by a solid catalyst, the rate is determined by the number of active sites on the catalyst surface, so increasing pressure does not alter the rate

Answer 81

Only surface area can react, larger SA increased frequency of collisions, increased frequency of collisions, increased frequency of successful collision

Answer 82

Minimum KE the colliding molecules must posses for the collisions to be successful and result in the formation of product molecules

Answer 83

DProduct/Dt Or -Dreactant/ Gradient of graph, either initial rate or at time t

Answer 84

Ecat is lower than initial Ea, larger fraction of molecules above ecat line T hot line has peak shifted to the right but lower peak

Answer 85

Reactants products AH and Ea | For catalysed add a middle transition state

Answer 86

Rate of change of concentration of product or reactant with time

Answer 87

Time taken for reactants to half

Answer 88

Slowest step in a multi step mechanism

Answer 89

* Measure out samples of reactants with known conc, * Mix and start clock * stir throughly * at regular time intervals, withdraw samples using a pipettes and quench stop reaction either with ice or cold water or solution to react with one of the reactants. Note time where half the contents of the pipette have been added to the quenching solution * titrate solutions to find conc of reactant

Answer 90

Spectrophotometer can be used to measure conc of coloured species amount of light of frequency absorbed is measured at set time intervals this depends on conc

Answer 91

Average rate = mass lost/time Do the reaction in a conical flaks tarred when t=O, record mass loss over time in gradual intervals (Some liquid may be lost as spray, plug it with cotton wool, mass change is v small)

Answer 92

The moles of gas measured of product when less than ten percent of acid used up Rate inversely proportional to time for certain volume of gas to be produced

Answer 93

Initial rate = gradient of a conc time graph at t=0 Conc recatants falls by 10% or less to make initial rates valid, measure change in conc over time ``` Example: Iodine clock reaction H2O2 + 2I- -> I2 + 2H2O With starch and thiosulphate The thiosulphate reacts with the produced iodine. Thererefore the blue black colour is perceived only after the set amount of thiosulphate has been used up Blue black end point ``` Vary concentrations but keep total volume constant Sulphur clock S2O3^2- + 2H+ -> S + SO2 + H20 With nitric acid Time taken for a large X on a white tile to become Invisible

Answer 94

No reaction

Answer 95

Zero Order

Answer 96

First order

Answer 97

Second order

Answer 98

Zero order

Answer 99

First order

Answer 100

Second order

Answer 101

Anything involved in the rate equation is involved in or before the rate determining step

Answer 102

Colorimeter Acid catalyst - dark brown I2 -> colourless Vary concentrations and keep total volume constant Rate = k [propanone] [H+]

Answer 103

Iodine not involved in or before the rate determining step •Lone pair on oxygen attacks H+ pos charge moves onto carbon (CH3)2C+OH), arrow from one of the hydrogens on CH3 to form double bond - this is slow step as C-H bond is broken CH2=C(CH3)OH •arrow from OH bond to carbon, then from double bond to I , from the I-I bond to the other I, Forms H3C-CO-CH2I + I-

Answer 104

SN1 R=k[halogenoalkane] not involved in rate determining step - tertiary SN2 R=k[halogenoalkene][nucleophile] - primary Evidence for the mechanisms involved

Answer 105

If it is catalysed by something in the solid state, the limiting factor is the availability of active sites. Unless the pressure is extremely low Adsorption fast Slow step is adsorbed reactants to adsorbed products Adsorbed products to gaseous products is fast

Answer 106

If the conc of the reagent is at least ten times that of the other reagent, the change in conc during reaction will be negligible. This means that within experimental error it appears to be constant and rate equation. Is r = k * what appears to be constant [B]^q * [A]

Answer 107

Compounds with the same molecular formula but different structural formula

Answer 108

Compounds with the same structural formula but which have the atoms arranged differently in space Split into geometric and optical isomerism

Answer 109

Is a type of stereoisomerism caused by the presence of a functional group that restricts rotation Eg double bonds or cyclic compounds

Answer 110

Do not have a plane of symmetry. They are chiral. They are two isomers which are non superimposable mirror images, two enantiomers.

Answer 111

* The nature of the enantiomer * The concentration of the enantiomer in the solution * The length of reaction tube

Answer 112

* primary and secondary alcohols turn orange acidified potassium dichromate (VI) solution to a green Cr3+ solution. Tertiary are not oxidised, remains orange * by distilling off the product as the former, and then doing a test with tollens, only aldehyde would reduce silver ion complex to give silver mirror, this would come from the secondary alcohol

Answer 113

Addition of sodium hydrogencarbonate or sodium carbonate. Has evolved RCOOH + NaHCO3 -> RCOONa + H20 + CO2 Gas turns limewater cloudy CO2 + Ca(OH)2 -> CaCO3 + H20

Answer 114

Region below 1500cm^-1, it shows a series of peaks that dependant on the exact compound being analysed.

Answer 115

The purer the compound the closer it matches database. Any stray peaks will be due to impurities

Answer 116

The extend of the splitting depends on the strength of the magnetic field. Therefore there must be some comparison. TMS is used - dissolved in solvent which does not contain any protons

Answer 117

Caused by the extent to which the electrons in orbit around the hydrogen nucleus are pulled away from the hydrogen (deshielding) the chemical shift is less for Ch3 than CH2 because the carbon is pulling electrons away from theee groups

Answer 118

The magnetic environment of a proton in one group is affected by the magnetic field of protons on the neighbouring carbon atoms •if a neighbouring group have opposite spin from another compound it results in two different fields affecting the CH2 so their peaks are split in two

Answer 119

The change of two C-13 atoms being next to each other in the carbon chain is about 1 in 1000 This is also why peak heights are not prioritising to the number of carbon in each environment

Answer 120

* column packed with a solid of inform particle size- stationary phase * sample is dissolved in suitable solvent and added to top of column, liquid eluent is forced through column under high pressure * it has a high resolution because the high pressure increases the speed at which the eluent passes through the column and so reduces the extent to which the band of a component spreads out due to diffusion * non polar stationary phase, polar eluent * connect column to infrared spectrometry

Answer 121

The time taken for a component in the sample mixture to pass through the column

Answer 122

* inject a sample into a chromatography column in a thermostatically controlled oven * sample evaporated and is forced through column by flow of inert, gaseous mobile phase, called carrier gas (hydrogen, argon, oxygen, nitrogen or air). Column contains a liquid stationary phase that is adsorbed onto surface of inert solid * useful for separating mixtures of gases or volatile liquids. * remove the samples, measure mass and use NMR/IR compare with database Useful for forensic work and detention of drugs in urine sample

Answer 123

Alkanes have higher bp because the rigidity of the double bond does not allow the molecules to pack together as efficiently Halogenoalkanes are the highest because they contain more electrons so have more London forces

Answer 124

Insoluble because they cannot hydrogen bond

Answer 125

Large enough difference in the boiling temps of organic substances then distillation can be used to separate them •round bottomed or pear-shaped flask •a still-headed fitted with a thermometer the bulb must be positioned level with outlet of still head •condenser with water going in at bottom and leaving at the top •open receiving vessel •electric heater Collect 2 degrees either side

Answer 126

Hydrolysed to salt of carboxylic acid heat under reflux with NaOH RCN + H20 + NaOH -> RCOO-Na+ + NH3 (To then get carboxylic acid use a strong acid after) Acidic hydrolysis dilute HCl RCN + 2H2O + HCl -> RCOOH + NH4Cl under reflux with lithium aluminium hydride LiAlH4 in dry ether and then hydrolyse with H2SO4 aq to form amine

Answer 127

rR-OCl + 4[H] -> rRHOH + HCl dry ether

Answer 128

No as they cannot hydrogen bond

Answer 129

Ortho Para Directing

Answer 130

Can hydrogen bond so melts higher than benzene which only has london forces Also soluable unlike Benzene as can hydrogen bond

Answer 131

Not Friedel crafts Oxygen atom acts as nucleophile and attacks carbon atom forming an Easter

Answer 132

Hydrogen bonding therefore higher than comparison alkane (also soluable)

Answer 133

•thin layer chromatography Stationary phase is either silica gel aluminium oxide immobilised on a flat inert sheet made from class or plastic •unknown amino acid mixture is dissolved in suitable solvent and a spot of dissolved known amino acid is placed separately on the same plate at the same level •the plate is then dipped in suitable eluent with spots above the level of liquid eluent •place in sealed container •capillary action draws up eluent •plate left until eluent has risen up to the top of the plate •remove plate and spray with ninhydrin and heat •ninhydrin reacts with amino acids producing a blue purple colour Compare with the heights reacted by known amino acids

Answer 134

Carboxylic acid is strongest -> two oxygen groups Phenol is second as the lone pair can be delocalised into pi system -> stabilises conjugate base Alcohol weakest

Answer 135

Use two lines, one solid triangle and one dashed line The entanioner has the same type of line drawn to each group but the groups are reversed like a mirror image

Answer 136

To remove soluble impurities but to ensure as little solid as possible dissolves

Answer 137

Source of nucleophile can carbon

Answer 138

They provide a surface for bubbles to form They distribute the heat more evenly

Answer 139

Collection over water/ gas syringe Ceramic fibre/ wool soaked in substance to be cracked Aluminium oxide Heat under catalyst

Answer 140

The rest of group one are metals Hydrogen does not react in the same way, has different chemical properties Forms H- ion

Answer 141

Chlorine and bromine | Iodine only if the C=C bond is activated by an oxygen atom

Answer 142

HI > HBr > HCl because the HCl bond the weakest Gaseous

Answer 143

Heat under 1000 atm pressure in the presence of trace of oxygen Causes radicals to be formed that initiate the polymerisation reaction Or mix with a solution containing alkylaluminium and titanium chloride

Answer 144

Hazard is the potential to do harm | Risk is the probability of harm occurring

Answer 145

Chloro bromo methane and chloroethane are gases at RTP Iodomethane and higher members are liquids

Answer 146

Only works for tertiary Conc HCL heat under reflux Chloroalkane plus H20

Answer 147

The time taken to produce enough solid to hide a cross on a piece of paper

Answer 148

Measure pH at time intervals Remember pH is logorithmic Or when no of ions change measures electrical conductivity

Answer 149

Heat at 60 degrees using an electric heater Add potassium dichromate and did sulphuric acid Collect ethanol in flask surrounded by iced water Distill off directly to prevent further oxidation Electric heater as organic stuff is flammable

Answer 150

Potassium dichromate sulphuric acid Round bottomed flask Reflux condenser Heat Aromatic can be done using Fredel-crafts

Answer 151

Sodium hydroxide reacts withs with iodine to form IO- and I- and H20 The IO- ions substitute into the CH3 group next to the C=O group forming CI3COR the electron withdrawing effect of the three halogen atoms and the oxygen atom weakens the σ bond which then breaks, and then OH- adds forming iodoform

Answer 152

* oxidation of primary alcohol * oxidation of aldehyde * hydrolysis of an Easter * hydrolysis of a nitrile * iodoform then add excess strong acid

Answer 153

Carboxylic acid + sodium carbonate -> salt of acid plus co2 plus h20 Turns limewater cloudy

Answer 154

Carboxylic acid plus PCl5 -> POCl3 plus acyl chloride plus HCl

Answer 155

HCl gas is lost hence irreversible Lower activation energy Cl is a better leaving group

Answer 156

Nickel catalyst and heat

Answer 157

Bellow 50 too slow | Above 60 Second NO2 group substitutes

Answer 158

Can hydrogen bond hence higher melting temp | Also soluble

Answer 159

Reacts with dilute nitric acid | 1,4

Answer 160

Alcohol not very acidic - no litmus no sodium hydroxide no sodium carbonate Phenol - litmus goes red, salt formed with NaOH, no reaction with sodium carbonate Carboxylic acid does all three

Answer 161

Heat under reflux with aq acid or alkali Acid Amide + H+ + H20 -> CH3COOH + NH4+ Alkali Amide + OH- ->salt of carboxylic acid plus NH3

Answer 162

TLC Stationary phase is either silica gel or aluminium oxide immobilised on a flat inert sheet that is usually made from glass or plastic •acid or mixture dissolved in a suitable solvent and a spot of the test solution is placed 2cm from bottom •known amino acid placed at the same level •plate dipped in mobile phase with the spots above the level of the liquid eluent •plate placed in sealed container •the eluent is drawn up by capillary action •plate left until eluent has risen to top •plate removed and sprayed with a solution of ninhydrin and then heated •ninhydrin reacts with amino acids producing a blue purple colour

Answer 163

Head on overlap between orbitals from neighbouring carbon atoms to form a sigma bond The remaining orbitals overlap sideways and so electrons delocalise around the ring

Answer 164

* Reprocessing polymers into simpler compounds for use in feedstock and chemical industry * Capture and use of energy from incineration * sorting and recycling of polymers * removal of toxic products formed during incineration

Answer 165

Restricted rotation around the C=C bond because the π bond prevents it

Answer 166

Head on overlap between orbitals from neighbouring carbon atoms to form a sigma bond The remaining orbitals overlap sideways and so electrons delocalise around the ring

Answer 167

* Reprocessing polymers into simpler compounds for use in feedstock and chemical industry * Capture and use of energy from incineration * sorting and recycling of polymers * removal of toxic products formed during incineration

Answer 168

Restricted rotation around the C=C bond because the π bond prevents it

Answer 169

Nitrile + 2H20 + H+ -> Carboxylic acid plus NH4+ Strong acid heat under reflux

Answer 170

Transisomer is formed | Providing that the second chlorine for example adds on opposite side to the first chlorine