alcohols

Question 1

bond angles

Answer 1

all bonds 109.5 except H-O-C which is 104.5 as the oxygen has 2 lone pairs which repel more

Question 2

boiling points

Answer 2

relatively low volatility and high boiling points due to hydrogen bonding

Question 3

partial oxidation of primary alcohols reaction, reagents, conditions

Answer 3

forms an aldehyded
potassium dichromate VI and dilute sulfuric acid
warm gently and distil out the aldehyde as it forms

Question 4

equation of primary alcohol partially oxidised to form aldehyde using propan-1-ol

Answer 4

CH3CH2CH2OH + [O] = CH3CH2CHO + H2O

Question 5

observation when any alcohol oxidised

Answer 5

orange to green as the dichromate reduces to green Cr3+ ion

Question 6

full oxidation of primary alcohols reagents, reaction, conditions

Answer 6

forms carboxylic acid
potassium dichromate VI and dilute sulfuric acid
heat under reflux and use excess dichromate

Question 7

fully oxidised primary alcohol equation using propan-1-ol

Answer 7

CH3CH2CH2OH + 2[O] = CH3CH2COOH + H2O

Question 8

oxidation of secondary alcohols reaction,reagents, conditions

Answer 8

forms ketone
potassium dichromate VI and dilute sulfuric acid
heat under reflux

Question 9

when do you need to show the position of the O in an aldehyde

Answer 9

when is has 5 or more carbons in the chain

Question 10

equation of secondary alcohol oxidised using propan-2-ol

Answer 10

CH3CHOHCH3 + [O] = CH3COCH3 + H2O

Question 11

why can tertiary alcohols not be oxidised by potassium dichromate VI

Answer 11

because there is no hydrogen atom bonded to the carbon with the OH group

Question 12

how to test for carboxylic acid

Answer 12

add sodium carbonate and it will fizz and produce CO2

Question 13

reaction of alcohols with dehydrating agents reagents, products, conditions, TYPE OF REACTION

Answer 13

forms alkene
conc sulfuric acid or phosphoric acid
warm under reflux
acid catalysed elimination

Question 14

definition of dehydration reaction

Answer 14

the removal of a water molecule from a molecule

Question 15

equation of alcohol dehydrated to form alkene using propan-1-ol

Answer 15

CH3CH2CH2OH —> CH2=CHCH3 + H2O

Question 16

two methods to produce ethanol

Answer 16

fermentation and hydration of ethene

Question 17

fermentation conditions, equation, reagents

Answer 17

glucose —-> ethanol + CO2
Yeast
No air
30-40 degrees temperature

Question 18

why is fermentation done with no air and at 30-40 degrees

Answer 18

no air - can end up forming carboxylic acid

38 degrees optimum temperature for enzymes, best speed, too high yeast denatures

Question 19

advantages and disadvantages of fermentation

Answer 19

advantages - renewable, cheap equipment

disadvantages - slow, not pure (needs to be distilled to purify), depletes land for crops

Question 20

fermentation symbol equation

Answer 20

C6H12O6 = 2CH3CH2OH + 2CO2

Question 21

ethene hydration reaction info

Answer 21

high temperature 300 degrees
high pressure 70atm
strong acidic catalyst conc H3PO4
acid catalysed addition mechanism

Question 22

hydration of ethene symbol and word equation

Answer 22

ethene + water = ethanol

CH2=CH2 + H2O —-> CH3CH2OH

Question 23

advantages and disadvantages of hydration of ethene

Answer 23

advantages - faster, purer, continuous process

disadvantages - high tech, non-renewable as it comes from crude oil, high energy costs

Question 24

equations to show ethanol is carbon neutral

Answer 24

photosynthesis
6CO2 + 6H2O = C6H12O6 + 6H2O

fermentation and combustion
C6H12O6 = 2CH3CH2COH + 2CO2
2CH3CH2COH + 6O2 = 4CO2 + 6H2O

6 for 6 therefore neutral

Question 25

issues with carbon neutral theory

Answer 25

doesnt take into account energy needed to irrigate plants and distil the ethanol or processing the fuel