Esters

Question 1

what functional group do esters have?

Answer 1

-COO-

Question 2

how are esters formed?

Answer 2

alcohol + carboxylic acid -> ester + water

Question 3

what catalyst is used to form esters?

Answer 3

acid catalyst e.g. sulfuric acid

Question 4

what do ester names end in?

Answer 4

-oate

Question 5

how are ester names formed?

Answer 5

the alcohol forms the first part of the ester names, and the acid forms the second part

e.g. ethanol + ethanoic acid -> ethyl ethanoate + water

Question 6

experiment to show reaction between alcohols and carboxylic acids

Answer 6

1. add a few drops of concentrated sulfuric acid to a boiling tube using a droplet pipette
2. add about 10 drops of ethanoic acid
3. then add an equal volume of ethanol
4. place the boiling tube in a beaker of water and place on a tripod
5. heat using a Bunsen burner until the water starts to boil and then turn it off
6. after one minute, remove the tube and allow it to cool
7. once it’s cool, pour the mixture into a test tube of sodium carbonate solution and mix - a layer of the ester should form on top of the solution

Question 7

what are properties of esters?

Answer 7

• they have pleasant smells - often sweet and fruity
• they are volatile - they evaporate into gases easily

Question 8

what are esters used for?

Answer 8

• perfumes - the evaporated molecules can be detected by smell receptors in your nose
• food flavourings