chemistry - esters

what are esters formed from?

an alcohol and a carboxylic acid with the presence of an acid catalyst

what is the by product formed when an ester is formed?

water

what is the functional group of an ester?

-COO-

what do the names of esters end in?

-oate

how are the names of esters formed?

alcohol prefix + yl carboxylic acid prefix+ anoate

what ester would the reaction of ethanol and ethanoic acid form?

ethyl ethanoate

how do you draw the displayed formula of an ester?

• cut off the -O-H group from the acid

• cut off the final -H from the alcohol (have OH facing left)

• squish together:

  • acid on left, alcohol on right

how do you write the structural formula of an ester?

• acid first, then alcohol

• CH₃CH₂…COOCH₂…CH₃

• (H for methanoic acid)

what is the structural formula of ethyl ethanoate?

CH₃COOCH₂CH₃

what is the displayed formula of ethyl ethanoate?

how would you prepare an ester in a lab?

• add a few drops of concentrated sulfuric acid to a boiling tube using a pipette

• add 1cm³ ethanoic acid and the same volume of ethanol

• place the tube in a beaker of 80C water for 5 minutes

• pour the mixture into a test tube of sodium carbonate solution and mix

• a layer of ester should form on top

what are the properties of esters?

• fruity smells

• sweet smells

• volatile - evaporate easily

what are the uses of esters?

• perfumes

• flavourings