paper 2 and 3 but all organic

Give an equation for the preparation of 1,6-diaminohexane by the reaction of 1,6-dibromohexane with an excess of ammonia.

Br-(CH2)6-Br + 4NH3 → H2N-(CH2)6-NH2 + 2NH4Br

1,6-Diaminohexane can also be formed in a two-stage synthesis starting from 1,4-dibromobutane. Suggest the reagent and a condition for each stage in this alternative synthesis.

KCN AQEOUS ALCOHOL

lalh4 in dry ether - aqueous

justify statement that no chiral carbons

no carbon atom is attached to 4 different groups

butA 1-3 DIene

when drawing the repeating unit, alway remember

the trailing bonds

why are addition polymers non bio degradable

carbon carbon bonds, cannot be hydrolysed

carbon carbon bonds, are non polar

why does alcohol have a higher boiling point than ketone

1) alcohol, has H bonds BETWEEN MOLECULES, ketone has dipole dipole intermolecular forces

2) more energy is required to overcome the H bonds

suitable reagent for the hydrolysis of a protein

CONC HCL

why was it necessary to use two different solvents

some of the amino acids did not separate, with the first solvent

some of the amino acids, have the same RF value

why can … be distinguished by high res mass spectrometry, even if same mr

the precise relative formula masses, are different

how does co2 cause global warming

c=o bonds in co2 absorb ir radiation

ir radiation EMITTED by earth, does not escape

state meaning of the term complementary in dna

A TO T

C TO G

explain why sodium borohydride reduces aldehyde, but not alkene

1) nucleophile is attracted to the delta positive carbon

2) the c double bond c is electron rich

3) the nucleophile is repelled by the c=c

name the type of compound shown by the formula RCOOK (coconut oil and KOH)

carboxylate salt

uses of carboxylate salt

SOAP, detergent surfactant

why is aqueous ethanol a suitable solvent when heating oil w KOH

acts as a MUTUAL solvent

to ensure reactants are miscible

meaning of fraction

GROUP OF HYDROCARBONS, with similar boiling points

why does co2 absorb IR radiation

c=o vibrates at the same frequency of IR

how is bioethanol produced

1a Photosynthesis (is the natural process in plants that takes CO2 from the air)

1b Fermentation (is the process used to make bioethanol releasing some CO2)

1c Combustion (is the process where bioethanol is burned and releases CO2)

equations for the formation of bioethanol

2a 6CO2 + 6H2O → C6H12O6 + 6O2

2b C6H12O6 → 2C2H5OH + 2CO2

2c 2C2H5OH + 6O2 → 6H2O + 4CO2

environmental issues with bioethanol

deforestation, sacrifice land that could be used for fuel

loss of biodiversity habitat

fuel used in production and distribution

suitable table for the combustion practical

two disadvantages of using a glass beaker on a tripod and gauze instead of …

1) glass is a poorer CONDUCTOR than …

2) tripod and gauze would have a fixed height above the flame

3) tripod and gauze would reduce heat transfer

why is benzene more thermodynamically stable

PI electrons delocalised

reagent needed for dehydration

conc H2So4

ethanol —>ethene + water

electrophilic addition equation w br2

why is fewer steps better

less energy used

better yield

why is high percentage atom economy better

less waste, less pollution

state how cfcs form chlorine atoms in the upper atmosphere

c-cl bonds broken homolytically

suggest why 1cm³ portions of the reaction mixture is added to an excess of NaHCo3

The sodium hydrogencarbonate solution neutralises the acid (catalyst)

So stops the reaction

how does graph show reaction is zero order with respect to iodine

volume/time graph

The graph is a straight line / has a constant gradient

So the rate of reaction does not change as the concentration (of iodine) changes / the iodine is being used up at a constant rate.

graph that shows 0 order w respect to time

use evidence from the equation to explain why…. is the rate determining step

… contains all the species in the rate equation

aparatus for reflux

when shaking mixture, what precaution should you take

 Remove stopper/bung OR tip the funnel upside down and open

the tap

there would be a build up of pressure

equation for the formation of the electrophile for electrophilic substitution of benzene

use of amine

MANUFACTURE of dyes

why would using a conical flask instead of a beaker give more accurate results

reduces loss of liquid droplets

suggest why chloroethanoic acid, is stronger than ethanoic acid

M2 Cl is an electron withdrawing group or negative inductive effect

M3 Weakens the O-H bond / increase polarity of O-H bond

how do you know… rds

ONLY LOOK AT RATE EQUATION

• can say slowest step

condition for KCN nucleophilic substitution

AQUEOUS + ETHANOL

reagent and condition needed for reduction of nitrile to amine

lial4 in dry ether

acid used to acidify dichromate

sulfuric acid

why is fractional distillation preferred over simple distillation

… have similar boiling points

how would experimental enthalpy of combustion differ from data book value

it would be lower, less exothermic

incomplete combustion

labelled maxwell boltzman cuve

when calculating q=mcdelatat what should be the unit of the mass of water

GRAMS

what is kevlar made from

benzene 1,4 dicarboxylic acid

1,4 di amino benzene

nylon 6,6

hexanedioc acid 1,4 diamino hexane

polyamide

polyester

terylene

dicarboxylic acid and diol

benzene 1,4 dicarboxylic acid ethane 1,2 diol

conditions for base hydrolysis of esters

AQUEOUS

formation of biodiesal

triester and methanol, makes glycerol and methyl esters

KOH as a catalyst

apparatus, for measuring volume of gas

why does chlorobenzene, not react with ammonia

electron rich ring or benzene or pi cloud repels nucleophile/ammonia

why is ethanoic anhydride not used in industrial synthesis

Corrosive OR forms strong acid/HCl (fumes) OR vulnerable to hydrolysis OR dangerous (to use)

KCN

AQUEOUS ALCOHOL

why is 3 aminopentane a stronger base than ammonia

lone pair on N more available, because of alkyl postive inductive effect

why is the halogenoalkane attacked by the nucleophile

bromine more electronegative than carbon

CARBON IS PARTIALLY POSITIVE

electron pair donated to the partially positive carbon

aldehyde to hydroxy nitrile

KCN & (dil) acid

fractional distillation

ozone depletion

formation of electrophile no2+

first order graph

second order

0 order

why would raising temp by ten degrees have a much greater effect on the rate of reaction, than doubling conc

Reaction occurs when molecules have E≥Ea

Raising T by 10 °C causes many more molecules to have this E

Whereas doubling [E] only doubles the number with this E

boiling point of alkene ketone alcohol

alkene lowest, ketone, alcohol

which alcohols cannot be dehydrated

alcohols where the adjacent carbon, does not have any hydrogens attached to it

how do h bonds form in a protein

Nitrogen and oxygen are very electronegative Therefore, C=O and N–H are polar Which results in the formation of a hydrogen bond between O and H In which a lone pair of electrons on an oxygen atom is strongly attracted to the δ+H

why are polyesters biodegradable

Polar C=O group or δ+ C in Q (but not in P) Therefore, can be attacked by nucleophiles (leading to breakdown)

enthalpy of lattice dissociation

the enthalpy change, when one mol of a solid ionic compound DISSOCIATES FULLY into its gaseous ions

main difference of value of enthalpy of solution

HEAT GAIN FROM SURROUNDINGS

or incomplete dissolving

definition of steroisomers

1) Same molecular formula

2) Different spatial arrangement of ATOMS

why can … not experience e/z isomerism

two of the same groups on one of the C=C

quicker formation of ppt for halides and silver

carbon halogen bond strength decreases down the group

why is the reaction fastest at the start

1) high conc of reactants

2) more frequent successful collisions

why is ethanoic anhydride preferred to ethanoyl chloride in aspirin practical

1) ethanoic acid less corrosive

2) is not vulnerable to hydrolysis

why is reflux not essential when flask is heated to 85 degrees for ten mintues

boiling points are above 85 degrees

none of them will boil

filter under reduced pressure apparatus

recrystallisation practical

how would you know if the product is impure

would melt over a larger range of TEMPERATURES

the melting point value would be lower than the data book value

why is loose cotton wool instead of leaving flask open

to avoid acid/solution/liquid

escaping

OR to avoid (acid/solution/liquid) splashing/spraying/spitting

why is loose cotton wool instead of inserting a bung

allow CO2 to escape

state how graph shows rate = k[Hcl]

straight line and through the origin

what variables can be measured to investigate rate of reaction at constant temperature

• volume of gas / CO2

• pH

• concentration of HCl/acid/H+

• conductivity

why would add NAOH dropwise around the equivalence point

as there is a large pH change (for a small addition of alkali) 

how does buffer buFF Ph

M1 OH– reacts with propanoic acid OR reacts with H+

M2 EITHER

ratio of [CH3CH2COOH] to [CH3CH2COO–] remains almost

constant

why would methyl orange not be a suitable indicator to use

would not change colour at the equivalence

point

why would universal indicator not be suitable

idea of range of colours during titration /

no distinct colour change

why increase in rate of reaction when a catalyst is added at a constant temp

the PROPORTION OF SUCCESSFUL COLLISONS INCREASES

decrease in activation energy

what is formed by the acid hydrolysis of phenyl benzenecarboxylate

c6h5cooH

why are polyesters biodegradable but polyalkenes are not

polyesters: C=O

polyalkenes: (only) C−C

polyesters are susceptible to nucleophilic attack

safety precautions when filling the burette

• fill bellow eye level

• if toxic wear gloves

dioate in burette and manganate

colourless to pink

(not safety) why is KCN used rather than HCN

[HCN] weak

describe enthalpy of solution practical

Stage 1 Method (1a) Measures water with named appropriate apparatus (1b) Suitable volume/mass / volume/mass in range 10 – 200 cm3 /g (1c) Into insulated container / polystyrene cup (NOT just ‘lid’) (1d) Add known mass of MgCl2(s) (1e) Use of ‘before and after’ weighing method. NOT ‘added with washings’

Stage 2 Measurements (could mark from diagram) (2a) Record initial temperature (min 2 measurements) (2b) Record T at regular timed intervals for 5+ mins / until trend seen (2c) Plot T vs time

Stage 3 Use of Results (3a and 3b could come from diagram) (3a) Extrapolate lines to when solid added (to find initial and final T) (3b) Tfinal – Tinitial = ∆T / idea of finding ∆T from graph at point of addition (3c) q = mc∆T (3d) amount = mass/Mr (0.80/95.3 = 8.39 x 10–3 mol) (3e) ∆Hsoln = q/8.39 x 10–3 or in words

in graph of delta g against temperature what is the gradient

- minus deltas s

role of sulfuric acid in the formation of ketone from alcohol

OXIDISING AGENT

Role of sulfuric acid with nacl

proton donor

explain why excess of NaOH used when reacting with ester

To ensure that the ester is completely hydrolysed / to ensure all the ester reacts