Chapter 14

Question 1

What are the two different ways ethanol can be made

Answer 1

Hydration of ethene and fermentation

Question 2

Properties of methanol

Answer 2

Clean burning
Fuel additive in high performance cars
Starting material in many industrial syntheses
Toxic causes severe organ damage then death

Question 3

Uses of ethanol

Answer 3

Alcoholic drinks
Perfumes
Cleaning fluids
Mouthwash
Fuel- up to 10% added to increase octane rating and make fuel burn more cleanly
Added to methanol to make methylated spirits- solvent for removing paints

Question 4

What is the suffix for an alcohol with two OH groups

Answer 4

Diol
*chain name not shorted as diol doesn’t begin with vowel eg butanediol

Question 5

Properties of alcohol

Answer 5

High mp and bp due to hydrogen bonding
Lower volatility compared to alkanes with a similar mass due to hydrogen bonding

Question 6

How does volatility change as bp changes

Answer 6

As volatility increases the bp decreases

Question 7

Describe and explain the trend in bp of alcohols

Answer 7

Bp increases as molecular mass increases ( chain length increases)
Strength of London forces increase due to more surface area contact and hydrogen bonds increase meaning more energy is needed to overcome the bonds

Question 8

Why do alcohols dissolve in water and what is the pattern

Answer 8

Because hydrogen bonds form between the polar OH groups of the alcohol and the water molecule
Solubility decreases as the chain length increases (the first 3 are soluble) because as the molecule increases in size the amount of non polar region increases so solubility decreases

Question 9

What is a primary alcohol

Answer 9

OH group attached to a carbon with two hydrogens and ONE alkyl group
Or three hydrogen atoms in methanol

Question 10

What is a secondary alcohol

Answer 10

OH group attached to a carbon atom bonded to TWO alkyl groups

Question 11

What is a tertiary alcohol

Answer 11

OH group attached to a carbon atom bonded to THREE alkyl groups

Question 12

Equation for hydration of ethene

Answer 12

Ethene + water ——> ethanol

Question 13

Conditions for hydration of ethene

Answer 13

300 degrees c
60 atm
Catalyst = H3PO4

Question 14

Raw material and type used in hydration of ethene

Answer 14

Crude oil
Finite

Question 15

Hydration of ethene
Type of process
Reaction rate
Purity of ethanol

Answer 15

Continuous
Fast
Pure

Question 16

Equation and conditions for fermentation

Answer 16

Glucose ——> ethanol + carbon dioxide
37 degrees c
Atmospheric pressure
Catalyst = zymase ( an enzyme in yeast)

Question 17

Fermentation
Raw material
Raw material type

Answer 17

Carbohydrate crops eg sugar
Renewable

Question 18

Fermentation
Type of process
Reaction rate
Purity of ethanol

Answer 18

Batch - wait for product to be made remove cleans d begin again
Slow
Impure must be purified by fractional distillation

Question 19

What is the structural formula for alcohol

Answer 19

COH

Question 20

What is the structural formula for an aldehyde

Answer 20

CHO

Question 21

What are alcohols oxidised by and what is the colour change when oxidation occurs

Answer 21

Acidified Potassium dichromate
Orange to green ( dichromate ions to chromium iii ions)

Question 22

How do you get an aldehyde
What inorganic product is also formed

Answer 22

Gently heat a primary alcohol with acidified potassium dichromate
Distil product as formed to avoid any further oxidation
Use an excess of alcohol
Water

Question 23

Why does simple distillation work when producing aldehydes

Answer 23

Alcohol has hydrogen bonding so has a high bp, the aldehyde doesn’t so has a lower bp so can be distilled

Question 24

How do you produce a carboxylic acid

Answer 24

Heat a primary alcohol under reflux so that it is oxidised twice to form a carboxylic acid from an aldehyde
Use a excess of oxidising agent

Question 25

How does reflux work

Answer 25

The aldehyde evaporates then condenses on the tube and drips back down to go through the second stage of oxidation

Question 26

Define reflux

Answer 26

The continual boiling and condensing of a reaction mixture to ensure that the reaction takes place without the contents boiling dry

Question 27

What occurs during the oxidation of secondary alcohols

Answer 27

Oxidised to produce ketones and cannot be oxidised further

Question 28

What is oxidation

Answer 28

The removal of hydrogen Can’t be further oxidised if there is no hydrogen to remove

Question 29

Can tertiary alcohols be oxidised

Answer 29

No

Question 30

What is dehydration of alcohols What is the reaction called What is required

Answer 30

Alcohol dehydrated to produce an alkene ( h and OH removed from either end and c-c double bond formed) Elimination reaction Acid catalyst H3PO4 or H2SO4

Question 31

What is an example of a substitution reaction How does it occur

Answer 31

Alcohol reacting with hydrogen halides to form haloalkanes Alcohol heated up under reflux with sulphuric acid and a sodium Halide as a hydrogen halide is to dangerous to use as a reactant The hydrogen halide then reacts with the alcohol The swaps with the oh group

Question 32

How do you produce an ester

Answer 32

Alcohol + carboxylic acid in an acid catalyst ( commonly con sulphuric acid ) OH comes off carboxylic acid and h comes off alcohol to produce water and the rest are brought together

Question 33

How do you name an ester

Answer 33

Alcohol provides the alkyl part of name Carboxylic acid provides the alkanoate part of the name