Alcohols

Question 1

What is the formula for Alcohols

Answer 1

CnH2n+1OH

Question 2

What is a primary alcohol?

Answer 2

This is when the OH group is attached to a carbon with 1 alkyl group.

Question 3

Explain the trend of boiling points as chain length increase?

Answer 3

As chain lengths increase, molecules get longer having more intermolecular forces so it increases

Question 4

Explain the Oxidation of Primary Alcohols

Answer 4

They can be oxidised by acidified potassium dichromate into an aldehyde and then further oxidised into a carboxylic acid. The colour change is from orange to green

Question 5

Explain the Oxidation of Secondary Alcohols

Answer 5

They can be oxidised into a Ketone by acidified potassium dichromate but not any further. Orange to green

Question 6

Explain the Oxidation of Tertiary Alcohols?

Answer 6

They cannot be oxidised

Question 7

Explain the process of Fermentation

Answer 7

This produces ethanol. Through anaerobic respiration.

C6H12O6 –> 2C2H5Oh + 2CO2

Question 8

State the compromise for Temperature when producing ethanol

Answer 8

Too low temp = Enzymes work too slow

Too high = enzymes will begin to denature and not function

So a compromise is made

Question 9

Explain the test to distinguish between aledehydes and Ketones using Tollens’ Reagent

Answer 9

Tollens’ is Ag(NH3)2OH and with Aldehydes you’ll see a silver mirror and in ketones no observation will be made

Question 10

Explain the test to distinguish between Aldehydes and Ketones using Fehling’s Solution

Answer 10

With Aldehydes a dark red ppt will form whereas in ketones it’ll remain blue

Question 11

What is the test for unsaturated hydrocarbons

Answer 11

Add bromine water and shake and if present the bromine water will decolourise

Question 12

Why is a compromise temperature of 35°C used in fermentation?

Answer 12

Greater than 40°C denatures Yeast

Question 13

Raw Material: Hydration of Ethene

Answer 13

Crude Oil

finite

Question 14

Define: Biofuel

Answer 14

Fuel derived/produced from Recently living, Renewable Biological sources

Question 15

Why is using Biofuels not completely Carbon Neutral?

Answer 15

Fossil fuels burned to power machinery:
|> Make fertilisers
|> Harvest crops
|> Refine fuel
|> Transport fuel
Produces CO₂

Question 16

Type of Process: Hydration of Ethene

Answer 16

continuous

Question 17

Raw Material: Fermentation

Answer 17

Sugar Crops

renewable

Question 18

What do Alcohols react to form in Elimination Reactions?

Answer 18

An Alkene

Question 19

Define: Functional Group isomers

Answer 19

Isomers w/ same molecular formula but different functional group

Question 20

Define: Position isomers

Answer 20

Isomers w/ same molecular formula but functional group is in a different position

Question 21

Quality of Product: Fermentation

Answer 21

Very Impure

Question 22

Conditions for Hydration of Ethene?

Answer 22

300°C

60 atm

Question 23

Define: Reflux

Answer 23

Boiling without gas escaping

Question 24

Why is the product of Oxidation of a Primary Alcohol most likely to be a Carboxylic Acid when formed through Reflux?

Answer 24

Aldehyde is Recondensed back into the flask so further Oxidation can occur