Alkenes and Alcohols

Question 1

what is the general formula of an alkene?

Answer 1

CnH2n

Question 2

why do alkenes react with electrophiles?

Answer 2

the double bond has lots of electrons so is easily attacked by electrophiles

Question 3

what is an electrophile?

Answer 3

electron pair acceptor

Question 4

what is a polymer?

Answer 4

long chain molecule formed when lots of small molecules (monomers) join together

Question 5

what type of polymers do alkenes form?

Answer 5

addition polymers

Question 6

why are polyalkenes with long straight chains stronger than those with short branched chains?

Answer 6

they can be packed more closely together so the VDW’d will be stronger

Question 7

give two typical uses of rigid PVC

Answer 7

drainpipes and window frammes

Question 8

what is the general formula for an alcohol?

Answer 8

CnH2n+2OH

Question 9

what is the method of producing alcohols from alkenes?

Answer 9

hydration of alkenes gives an alcohol

hydrate an alkene using steam in the presence of an acid catylist

Question 10

what is the method of producing alcohols from alkenes?

Answer 10

hydration of alkenes gives an alcohol

hydrate an alkene using steam in the presence of an acid catalyst

Question 11

why should fermentation of glucose not be carried out at more than 40*c?

Answer 11

that is the enzymes optimal temp
too cold and its too slow
too hot and it is denatured

Question 12

what is a biofuel?

Answer 12

a fuel that is made from biological material that’s recently died

Question 13

list two advantages of replacing fossil fuels with biofuels

Answer 13

biofuels are renewable so a more sustainable source of energy

its carbon neutral

Question 14

list two disadvantages of replacing fossil fuels with

biofuels

Answer 14

petrol car engines would have to be modified to use fuels with high ethanol concentrations

there will be less land to grow food on as its used up for growing biofuels

Question 15

how do you make ethanol from glucose?

Answer 15

fermentation of ethanol

Question 16

what is the colour change when potassium dichromate(VI) is reduced?

Answer 16

the orange dichromate ion is reduced to the green chromium ion

Question 17

describe the structure of an aldehyde

Answer 17

has a hydrogen and one alkyl group attached to carbon atom

functional group always on carbon-1
suffix is -al

Question 18

describe the structure of a ketone

Answer 18

two alkyl groups attached to carbon atom
suffix is -one
if there is more than 5 carbons say which carbon the functional group is on

Question 19

describe the structure of a carboxylic acid

Answer 19

has a COOH group at the end of the carbon chain

suffix is -oic acid

Question 20

what will acidified potassium dichromate oxidise secondary alcohols to?

Answer 20

ketone

Question 21

what are primary alcohols oxidised to?

Answer 21

aldehydes then carboxylic acids

Question 22

what are secondary alcohols oxidised to?

Answer 22

ketones

Question 23

what are tertiary alcohols oxidised to?

Answer 23

they aren’t oxidised

Question 24

describe two tests you can carry out to distinguish between an aldehyde and a ketone?

Answer 24

fehlings and benedicts solution are both deep blue and reduce to brick red when warmed with an aldehyde, but stay blue with a ketone

tollens reagent is reduced to form a silver mirror when warmed with an aldehyde, but not with a ketone