Esters

Question 1

What is an esterification reaction?

Answer 1

Alcohols and Carboxylic acids reacting together to make esters

Question 2

What is the functional group of esters?

Answer 2

-COO-

Question 3

Are esters compounds?

Answer 3

Yes

Question 4

What two things are esters used in?

Answer 4

Food Flavourings and Perfumes

Question 5

How is ethyl ethanoate formed?

Answer 5

Ethanoic acid will react with ethanol in the presence of concentrated sulfuric acid (catalyst) to form the ester ethyl ethanoate

Question 6

What features do esters have?

Answer 6

They are sweet smelling oily liquids

Question 7

What else is produced in an esterification reaction?

Answer 7

A molecule of water (H2O)

Question 8

What are esters made from?

Answer 8

Carboxylic acids reacting with an Alcohol

Question 9

What does an ester’s name always end with?

Answer 9

-anoate

Question 10

When naming an ester, what always takes the first part of the name?

Answer 10

The alcohol

Question 11

When naming an ester, what always takes the second part of the name?

Answer 11

The carboxylic acid

Question 12

Carboxylic acid + Alcohol ——>?

Answer 12

Ester + Water

Question 13

What is the water molecule made of during an esterification reaction?

Answer 13

The OH- ion from the carboxylic acid AND the H+ ion from the alcohol

Question 14

When drawing the displayed formula of an ester, what element joins the carboxylic acid and the alcohol?

Answer 14

An oxygen ion (O) from the end of the carboxylic acid which bonds with the end carbon (C) ion in the alcohol

Question 15

What is the structural formula of ethyl ethanoate?

Answer 15

CH3CO2CH2CH3

Question 16

Where is the double bond in an ester?

Answer 16

In the carboxylic acid between a carbon (C) and oxygen (O) atom

Question 17

What is the purpose of an acid catalyst in an esterification reaction?

Answer 17

To speed up the reaction (usually use concentrated sulfuric acid)

Question 18

What other term can be used to refer to the -COO- group in esters?

Answer 18

Ester link

Question 19

What is the only byproduct of an esterification reaction?

Answer 19

The water molecule (H2O)

Question 20

What is the structural formula of ethanoic acid?

Answer 20

CH3COOH

Question 21

What is the structural formula of ethanol?

Answer 21

CH3CH2OH

Question 22

Can you draw the displayed formula for ethyl ethanoate?

Answer 22

DRAW IT RIGHT

Question 23

What is the name of the ester that is formed by ethanol and propanoic acid?

Answer 23

Ethyl propanoate

Question 24

What is the name of the ester that is formed by butanol and methanoic acid?

Answer 24

Butyl methanoate

Question 25

What is the name of the ester that is formed by pentanol and ethanoic acid?

Answer 25

Pentyl ethanoate

Question 26

What other reaction can an esterification reaction be described as?

Answer 26

The reaction can also be described as a condensation reaction because water is made when two molecules join together

Question 27

What is ethyl ethanoate?

Answer 27

An ester

Question 28

What kind of compounds are esters?

Answer 28

They are volatile compounds with distinctive smell and are used as food flavourings and in perfumes

Question 29

What kind of smell are esters often described as having?

Answer 29

Esters are often described as having a sweet, fruity smell (they typically smell of bananas, raspberries, pears or other fruit because esters occur in all these natural products)

Question 30

How would you prepare a small sample of ethyl ethanoate?

Answer 30

METHOD: -obtain a test tube and add 6 drops of sulfuric acid to it -add 10 drops of ethanol to the same test tube -carefully add 10 drops of glacial ethanoic acid to the same test tube -gently warm the test tube in a water bath for a few minutes (ETHANOL IS FLAMMABLE SO A BUNSEN BURNER CANNOT BE USED) -obtain a 100cm3 beaker and measure approximately 25cm3 of sodium carbonate solution and pour into the beaker (to remove acidic impurities) -tip the contents of the test tube into the beaker, swirl gently and smell carefully by wafting fumes towards your nose from a distance of about 20cm