sc23, alcohols and carboxylic acids (paper 2)

Question 1

what is the molecular formula for alcohol

Answer 1

C n H 2n+1 OH

Question 2

how can ethanol be oxidised to ethanoic acid

Answer 2

• by chemicals called oxidising agents or
• the actions of microbes

Question 3

what is the mian acid in vinegar

Answer 3

ethanoic acid

Question 4

what is an alcohol

Answer 4

an alcohol forms a homologous series of compounds

Question 5

what do the names of alcohol end in

Answer 5

anol

Question 6

what functional group do all alcohols have

Answer 6

O-H (hydroxyl-

Question 7

true or false: alcohols have similar chemical properties

Answer 7

true

Question 8

true or false: alcohols don’t have similar chemical properties

Answer 8

false

Question 9

true or false: alcohols show a gradual variation in physical properties

Answer 9

true

Question 10

true or false: alcohols don’t show a gradual variation in physical properties

Answer 10

false

Question 11

what does the molecular formula of alcohol differ by

Answer 11

C H 2

Question 12

how is ethanol produced

Answer 12

from carbohydrates in aqueous solution by a process called fermentation

Question 13

where can the carbohydrates come from for producing ethanol

Answer 13

• fruit (e.g grape)
• breakdown os starch (from wheat or barley)

Question 14

what single-celled fungus helps speed up the production of ethanol by providing enzymes

Answer 14

yeast, a single-celled fungus

Question 15

give the word equation for the production of ethanol

Answer 15

glucose –> ethanol + carbon dioxide

Question 16

give the symbol equation for the production of ethanol

Answer 16

C6H12O6 (aq) –> 2 C2H6OH + 2 CO2

Question 17

what is the optimum tempurature for fermentation

Answer 17

35

Question 18

what happens when oxygen is present during fermentation

Answer 18

• aerobic respiration happens instead of anaerobic respiration
• so it produces only carbon dioxide and water

Question 19

how can we obtain the ethanol in the mixture with water

Answer 19

• fractional distillation
• chemically absorb the last small amount of water

Question 20

what is a carboxylic acid

Answer 20

carboxylic acids form a homologous series of compounds

Question 21

what do the names of carboxylic acids end in

Answer 21

anoic

Question 22

what functional group do all carboxylic acids have

Answer 22

= O
C
- O - H
carboxyl

Question 23

true or false: carboxylic acids have similar chemical properties

Answer 23

true

Question 24

true or false: carboxylic acids don’t have similar chemical properties

Answer 24

false

Question 25

true or false: carboxylic acids don’t show a gradual variation in physical properties

Answer 25

false

Question 26

true or false: carboxylic acids show a gradual variation in physical properties

Answer 26

true

Question 27

what does the molecular formula of carboxylic acids differ by

Answer 27

CH2

Question 28

what is the molecular formula for carboxylic acids

Answer 28

C n -1 H 2n-2 COOH

Question 29

are carboxylic acids weak or strong acids, why?

Answer 29

weak as they only partially dissociate into ions when they dissolve in water

Question 30

give the word equation for the dissociation of acids

Answer 30

carboxylic acid <–> carboxoate ion + hydrogen ion

Question 31

what three properties do carboxylic acids have in common with acids

Answer 31

• react with carbonates to produce salt, water and carbon dioxide
• react with reactive metals to produce a salt and hydrogen
• dissolve in water to produce acidic solutions