paper 2 things

Question 1

decomposition of ozone

Answer 1

Cl. + O3 –> ClO. + O2
ClO. + O3 –> Cl. + 2O2

Question 2

does halogenoalkane or alcohol functional group take priority?

Answer 2

alcohol

Question 3

what do nucleophiles do

Answer 3

donate electron pair

Question 4

what does nucleophillic addition do?

also what are reagents and conditions

Answer 4

gets rid of C=O bond (in aldehyde/ketone) by adding :CN- or :H- to form hydroxynitrile or alcohol respectively.

KCN/NaBH4 or LiAlH4 with dilute H2SO4

Question 5

give two ways of maximising the yeild of propanal obtained by distillation of the reaction mixture (or propanal, propan-1-ol and propanoic acid)

Answer 5

• keep temperature below the boiling point of the substance with the next lowest BP (in this Q 97C is BP of next)
• cool distillate

Question 6

How do you test for carboxylic acids?

Answer 6

sodium carbonate
will cause gas produced to turn limewater (calcium hydroxide) cloudy (CO2 produced)

Question 7

whats the name of

Answer 7

1-phenylpropan-1-ol

Question 8

what does the acyl chloride loose in nucelophillic addition-elimination

Answer 8

:Cl-

Question 9

What does the nucelophile loose in nucelophillic addition elimination reaction?

Answer 9

an H+

Question 10

what is the byrpoduct in nucelophillic addition-elimination reactions producing carboxyllic acids or esters
+ whats the observation

Answer 10

HCl
misty fumes

Question 11

what kind of primary amine CANNOT be formed by reducing a nitrile?

Answer 11

one with a methyl group attatched to C1 as in the carbon that the N atom is attatched to.

Question 12

production of ethanol -fermentation

reaction
temp
pressure
catalyst
other
raw material
type of process
reaction rate
purity of ethanol

Answer 12

C6H12O6 –> 2CH3CH2OH + 2CO2
35C
noraml atm pressure
enzyme in yeast
aqueous anaerobic
carbohydrate crops eg maize
batch (stop-start)
slow
impure (must be purified by fractional distillation)

Question 13

production of ethanol - ethene with steam (hydration)

reaction
temp
pressure
catalyst
other
raw material
type of process
reaction rate
purity of ethanol

Answer 13

CH2=CH2 + H2O –> CH3CH2OH
300C
70atm
conc phosphoric acid
crude oil
continuous
fast
pure

Question 14

acronym for products of fractional distillation of crude oil, bottom to top

Answer 14

Dr Kangaroo Not Good Fun

Diesel, Kerosene, Naptha, Gasoline, Fuel Gas

Question 15

thermal vs catalytic cracking
temo
pressure
products

Answer 15

thermal
temp: 900C
pressure: 70 atm
products: alkenes
catalytic
temp: 450
pressure 1-2atm
products: motor fuels (cyclic alkanes, aromatics, branched alkanes)

Question 16

reagents and conditions for nitration (electrophillc substitution)

Answer 16

• conc HNO3 and conc H2SO4
• warm

Question 17

generation of electrophile for nitration

Answer 17

HNO3 + 2H2SO4 –> NO3+ + 2HSO4- + H3O+

Question 18

why do carboxyllic acids have higher BP than alchols?

Answer 18

two hydrogen bonds form between molecules, holding them together in a dimer

Question 19

reagents and conditions of elimination in halogenoalkanes?

Answer 19

KOH dissolved in alcohol
reflux

Question 20

conditions of elimation in alchols

Answer 20

heat and excess conc H3PO4/H3PO4

Question 21

regents and conditions of electrophillic additon - hydration of alkenes

Answer 21

regents : H2O
conditions: high temp high pressure and conc H3PO4/H2SO4

Question 22

why can liquids (organic layer and aqueous layer) be seperates in the seperating funnel?

Answer 22

they are immisible

(not forming a homogeneous mixture when mixed)

Question 23

define displayed formula

Answer 23

structure drawn with all bonds shown

Question 24

how do nitriles react with water?

Answer 24

in two stages:
nitrile –> amide –> ammonium salt of carboxylic acid ie CH3COONH4 (requires 2 waters overall)
in reality this reaction is so slow that it is negligible.

Question 24

describe acid hydrolysis of nitriles | why is free acid formed instead of ammonium salt CH3COONH4

Answer 24

The nitrile is heated under reflux with dilute hydrochloric acid. Instead of getting an ammonium salt as you would do if the reaction only involved water, you produce the free carboxylic acid. (and ammonium chloride) eg CH3 + 2H2O + HCl --> CH3COOH + NH4Cl free acid formed instead because the ethanoate (A-) ions in ammonium ethanoate react with hydrogen from HCL to make ethanoic acid (HA) since thats a weak acid, holds on to the H+

Question 25

describe alkaline hydrolysis of nitriles | how would you make the product into a free carboxylic acid

Answer 25

The nitrile is heated under reflux with sodium hydroxide solution. This time, instead of getting an ammonium salt as you would do if the reaction only involved water, you get the sodium salt. Ammonia gas is given off as well. eg CH3CN + H2O + NaOH --> CH3COONa + NH3 ## Footnote add HCl,(or dilute H2So4) will react with A- ions in the same way to make HA

Question 26

describe acid hydrolysis of esters

Answer 26

ester + water ⇌ carboxylic acid + alcohol (H+ catalyst from conc H2SO4 - warm)

Question 27

describe the alkaline hydrolysis of esters

Answer 27

ester + alkali ⇌ carboxyl salt + alcohol must be done under reflux beacuse slow

Question 28

triglyceride + 3NaOH

Answer 28

--> glycerol + 3oap (RCOO-Na+)

Question 29

triglyceride + methanol requires what | what is a biodiesel

Answer 29

--> glycerol + 3RCOOCH3 KOH catalyst | Biodiesel is a mixture of methyl esters of long-chain carboxylic acids ## Footnote the product is biodiesel

Question 30

triglyceride + water

Answer 30

--> glycerol + 3RCOOH

Question 31

effect of Cl and CH3 on strength of acid

Answer 31

Question 32

halogenation of benzene | how, what needed why what make

Answer 32

Benzene reacts with chlorine or bromine in an electrophilic substitution reaction, (not an electrophillic addition reaction because benzene ring is too stable/strong) but **only in the presence of a catalyst.** and **heat under reflux** catalyst: The catalyst is either aluminium chloride (or aluminium bromide if you are reacting benzene with bromine) or iron. with chlorine--> chlorobenzene (C6H6 + Cl2-->C6H5Cl + HCl) with bromine--> bromobenzene (C6H6 + Br2-->C6H5Br + HBr) formation of electrophile: as Cl2 appraoches benzene ring the delocalised e- repel the e- in the bonding pair of Cl-Cl bond the slightly +ve end of the chlorine molcule acts as the electrophile. The presence of the aluminium chloride helps the polarisation, Cl- left over is gained by AlCl3--> AlCl4- then regular mechanism so H on benzene replaced by H+ which reacts with AlCl4- to get AlCl3 + HCl easy peasy!

Question 33

# iodine clock why keep overall volume the same?

Answer 33

The total volume must be kept constant so that the concentration of each reactant is proportional to volume.

Question 34

what is oevrall ROR determined by

Answer 34

the rate of the slowest step. The slow step of a reaction is known as the rate determining step (RDS).

Question 35

how does RDS relate to the rate equation

Answer 35

In any mechanism, species that are only involved in steps after the RDS do not appear in the rate equation. * However, species that appear in the steps up to, and including, the RDS are in the rate equation.

Question 36

with initial rate methods of determining order what do you plot

Answer 36

its using initial RATE so you do 1/time (1 because amount of iodine produced when thiosulfate used up should be constant, use X) for rate against conc

Question 37

what are continuous methods for dtermining rate and what do you plot at the end

Answer 37

- loss of mass - titration (when reaction incolves acid alkali, small samples removed and quenched by dilution or ice bath to stop reaction) (if it involves acid catalyst it can also be quenched using sodium carbonate-- removes acid catalyst) - colorimetry - pH measurements plot conc vs time, --> gradient = rate

Question 38

order of priority

Answer 38

- carboxylix acid - derivates (anhydrides, esters, acid halides, a**mides, nitriles**) - groups containg O or N (aldehydes, ketones, **alcohols, amines**) - alkenes - halides