4 Organics 2

Question 1

Use the method below to name the ester made from ethanol and methanoic acid

Answer 1

ethyl methanoate

Question 2

Esters are very volatile (evaporate easily) and smell or taste sweet. What are esters used for?

Answer 2

fragrances in perfumes OR flavourings in food

Question 3

What conditions are needed for microbial oxidation of ethanol?

Answer 3

Oxygen so that aerobic respiration can occur

30ºC

1 atm

Formation of ethanoic acid - vinegar

Question 4

Name the homologous series

Answer 4

carboxylic acid

Question 5

How do you know that the formation of ethanoic acid from ethanol is oxidation?

Answer 5

ethanol has gained oxygen

Question 6

What are the conditions needed in a fermenter?

Answer 6

30ºC

1 atm

no oxygen

Question 7

What type of reaction is shown below?

Answer 7

Complete combustion of ethanol

It is an exothermic reaction

Question 8

Draw the structural formula of ethanol

Answer 8

Question 9

What are products for the reaction between ethanoic acid and sodium carbonate

Answer 9

metal carbonate + acid –> salt + water + carbon dioxide

Question 10

Describe the conditions for fermentation of glucose

Answer 10

30ºC

yeast

1 atm

no oxygen (anaerobic)

Question 11

Name this molecule

Answer 11

-O-H group - therefore it is an alcohol

4 carbons

butan-1-ol

Question 12

Which homologous series does this molecule belong to?

Answer 12

alcohol

Question 13

Name the molecule

Answer 13

methanol

Question 14

What are the disadvantages of the addition of of ethene to make ethanol?

Answer 14

• expensive process - (high temp and pressure)
• non-renewable ethene is needed
• very technical process - needing expertise.

Question 15

What are the advantages and disadvantages of food such as corn being made into fuel (alcohol)?

Answer 15

Advantage: it is renewable

Disadvantage: It uses up land that would normally be used to grow food for people- this increases food prices

Question 16

Draw the dot cross diagram for ethanol

Answer 16

Question 17

Draw the displayed formula of ethanol

Answer 17

Question 18

Complete the word equation for fermentation of glucose with yeast

Answer 18

glucose –> ethanol + carbon dioxide

Question 19

Draw the displayed formula for propan-1-ol

Answer 19

Question 20

Name the ester

Answer 20

ethyl hexanoate

Question 21

Name the ester

Answer 21

ethyl butanoate

Question 22

What is the molecular formula of glucose?

Answer 22

C₆H₁₂O₆

Question 23

What conditions are needed to oxidise ethanol

Answer 23

potassium dichromate VI - oxidising agent

conc. sulfuric acid - catalyst

heat

NOT|E: mixture will turn from yellow to green

Question 24

Describe how to safely make and smell an ester from ethanoic acid and propanol

Answer 24

1. Place six drops of concentrated sulfuric acid into a test tube
2. Add 1 cm³ of ethanoic acid
3. Add 1 cm³ of propanol
4. Swirl gently and add the test tube to a hot water bath
5. Leave for 5 minutes
6. Pour the mixture into a beaker of sodium carbonate to neutralise the concentrated acid
7. Carefully waft the fumes towards your nose to identify the sweet ester smell

Question 25

Name the ester

Answer 25

ethyl propanoate

Question 26

Name the alcohol

Answer 26

propan-1-ol

Question 27

Name the products of anaerobic respiration of glucose by yeast

Answer 27

ethanol and carbon dioxide

Question 28

Name the functional groups which are identified on this molecule

Answer 28

red = carboxylic acid (COOH) green = ester (RCOOR')

Question 29

Name the two homologous series

Answer 29

alkane AND alcohol

Question 30

List the products of the following reaction

Answer 30

ethanol carbon dioxide

Question 31

What is the name of the container and cap needed for small scale fermentation of glucose AND explain why the special cap is needed.

Answer 31

Demijohn with a swan neck Swan neck allows CO₂ out (prevents it from exploding from pressure) but also stops oxygen from entering so that only anaerobic respiration of yeast occurs

Question 32

What is the function of potassium dichromate (VI) in the oxidation of alcohols

Answer 32

potassium dichromate (VI) is the oxidising agent It supplies oxygen [O] It, itself is reduced

Question 33

What are the advantages of making ethanol by addition of ethene using steam?

Answer 33

- no land needed to grow sugar cane - fast, continuous process - pure product of ethanol (100%)

Question 34

Name the products made from: sodium **carbonate** and ethanoic **acid** AND potassium **metal** added to propanoic **acid**

Answer 34

sodium hydroxide + ethanoic acid --\> **sodium ethanoate + water + carbon dioxide** potassium + propanoic acid --\> **potassium propanoate + hydrogen**

Question 35

Describe the condition for the addition reaction of ethene to ethanol

Answer 35

ethene + steam 300ºC Phosphoric acid catalyst 60 atm

Question 36

What are the disadvantages of making ethanol by fermentation?

Answer 36

- need land to grow sugar cane (reactant) - product is not 100% pure - (Only 14% since yeast dies) - slow, batch process - CO₂ is produced which is a green house gas

Question 37

What are the advantages of the fermentation process to make ethanol?

Answer 37

- uses a renewable source - such as sugar cane - cheap process - only 30ºC, no pressure - little technology needed to make it

Question 38

Identify the homologous series

Answer 38

ester

Question 39

Why is ethanoic acid a weak acid?

Answer 39

ethanoic acid does not fully dissociate into H+ ions Only 4 in 100 molecules dissociate - less H+ ions = weaker acid

Question 40

Name the homologous series depicted below

Answer 40

Carboxylic acid

Question 41

What type of reaction is esterfication?

Answer 41

Condensation reaction (water condenses out) leaving a carbon-oxygen bond between the carboxylic acid and alcohol

Question 42

Use the method below to name the ester made from propan-1-ol and butanoic acid

Answer 42

propyl butanoate

Question 43

In the process of fermentation, ethanol levels reach 14% before the yeast dies. How could ethanol be purified to 100%.

Answer 43

distillation

Question 44

Use the method below to name the ester made from butan-1-ol and propanoic acid

Answer 44

butyl propanoate

Question 45

What are the observations and products formed when magnesium is added to ethanoic acid

Answer 45

slight fizzing (as ethanoic acid is a weak acid) magnesium ethanoate + hydrogen Test for hydrogen- flaming splint goes squeaky pop

Question 46

Name the identified functional groups on this molecule

Answer 46

OH = alcohol COOH = carboxylic acid

Question 47

What would happen if fermentation of glucose was carried out in the presence of oxygen or aerobically?

Answer 47

ethanol would oxidise to ethanoic acid

Question 48

Name this salt

Answer 48

sodium ethanoate