5.3.3 - esters

Question 1

what type of molecules are esters

Answer 1

organic molecules

Question 2

when do esters form

Answer 2

when a carboxylic acid and an alcohol join together by losing an H2O molecule

Question 3

the ester functional group:

Answer 3

the ester functional group (-COO-) sits between two carbon chains, joining them together

(means there’s one O with a double bond coming out the C, and one O with a single bond coming out the same C)

Question 4

what is the general equation when a carboxylic acid and alcohol react

Answer 4

carboxylic acid + alcohol -> ester + water

Question 5

what is the ester formed when ethanoic acid and ethanol react

Answer 5

ethyl ethanoate

Question 6

what can the reaction between an alcohol and a carboxylic acid be called

Answer 6

condensation
or esterification

Question 7

making esters:

Answer 7

to prepare an ester, you would:
1) mix the carboxylic acid and alcohol together
2) add a few drops of concentrated sulfuric acid
-> this acts as a catalyst for the reaction
3) warm it for a while
4) tip the mixture into sodium carbonate solution
-> this neutralises the sulfuric acid catalyst, which is otherwise really corrosive
-> the reaction produces carbon dioxide so you wait until the fizzing has stopped

Question 8

what are the properties and uses of esters

Answer 8

esters are volatile compounds with distinctive smells
makes them suitable for use in food flavourings and perfumes