2.7 Alcohols and carboxylic acids

Question 1

What is fermentation?

Answer 1

an enzyme catalysed reaction that converts sugars to ethanol.

Question 2

What are the two methods of producing ethanol?

Answer 2

• Hydration of ethene using H20
• Fermentation using yeast

Question 3

In the hydration of ethene to make ethanol, what reagents and conditions are needed?

Answer 3

conditions of 300 degrees celcius a pressure of 60-70 atm and a phosphoric acid catalyst

Question 4

What occurs in the fermentation of sugars into ethanol?

Answer 4

dissolving the glucose in water, adding yeast and leaving the mixture in a warm place.

Question 5

what is the molecular formula of glucose?

Answer 5

C6H12O6

Question 6

What is biofuel and name two main examples:

Answer 6

Biofuel is a fuel that has been produced using a biological source such as from living organisms. Two main ones are bioethanol and biodiesel.

Question 7

What are the advantages of biofuel?

Answer 7

• They are renewable as plants can be grown each year and can also be made using waste materials from animals.
• They are carbon neutral. The overall production of carbon dioxide is reduced as any CO2 produced is reabsorbed by the plants during photosynthesis.
• countries that do not have access to fossil fuels or are not wealthy enough to deal with the changing prices of fossil fuels can use biofuel as a solution.

Question 8

What are the disadvantages of biofuel?

Answer 8

• Land used for biofuel is land that cannot be used to produce food and also could be the cause of habitat destruction.
• The amount of water and fertiliser needed to maintain the farms can be difficult.
• The carbon neutrality can also be questioned due to the factories and transportation needed for biofuel to be effective.

Question 9

What occurs in the dehydration of alcohols and what reagents are needed?

Answer 9

Alkenes are produced and dehydrating agents like conc sulfuric acid or aluminium oxide (heated)

Question 10

What do oxidising agents contain a lot of?

Answer 10

Oxygens

Question 11

What do reducing agents contain a lot of?

Answer 11

Hydrogens

Question 12

What oxidising agent is used for the oxidation of alcohols?

Answer 12

Acidified potassium dichromate
Cr2O7/H+

Question 13

What is the functional group of an aldehyde?

Answer 13

= O
C
- H

Question 14

What happens when a primary alcohol reacts with acidified potassium dichromate?

Answer 14

an aldehyde is made and upon further oxidation a carboxylic acid is made.

Question 15

What happens when a secondary alcohol is oxidised?

Answer 15

a ketone is made

Question 16

What happens when carboxylic acids when added to water?

Answer 16

They release H+ ions hence they are acidic.

Question 17

what is the equation for pH?

Answer 17

pH = -log10(H+)

Question 18

what is the equation for acid+base?

Answer 18

acid+base—>salt+water

Question 19

what is the equation when carboxylic acid reacts with carbonate? And how can this be tested

Answer 19

acid + carbonate -> salt + carbon dioxide + water
effervescence of CO2 and use lime water to prove this

Question 20

what is the reaction of alcohols and carboxylic acids?
and how can it be used as a test for both

Answer 20

esterification
carboxylic acids + alcohols -> ester + water
it is catalysed by concentrated sulfuric acid
gives a fruity smell sweet