Names and Formulae

Remember the pattern in naming chains of hydrocarbons

1 Carbon = methane CH4

2 Carbons = ethane C2H6

3 Carbons = propane C3H8

4 Carbons = butane C4H10

Alcohols

The functional group in an alcohol is -OH

To name them swap the –e for -ol

1 Carbon = methanol CH3OH

2 Carbons = ethanol C2H5OH

3 Carbons = propanol C3H7OH

4 Carbons = butanol C4H9OH

Alcohols

Q Why not write C2H6O?

The formula gives us clues about the structure of the moleculeThe oxygen and hydrogen in the alcohol functional group are bonded and so are written together

Carboxylic acids

The functional group in a carboxylic acids is -COOH

To name them swap the –e for –oic acid

1 Carbon = methanoic acid CH3COOH

2 Carbons = ethanoic acid C2H5COOH

3 Carbons = propanoic acid C3H7COOH

4 Carbons = butanoic acid C4H9COOH

EstersThese are made from the reaction of an alcohol

with a carboxylic acid – The formula is not required for esters but you will need to write

word equations

ethanol + ethanoic acid ethylethanoate

methanol + butanoic acid methylbutanoate

butanol + propanoic acid butylpropanoate

What do you notice about the naming of an ester?

Try out your theory on the next slide – click on the equation to reveal the answer

Esters

methanol + butanoic acid methylbutanoate

ethanol + propanoic acid ethylpropanoate

propylmethanoatepropanol + methanoic acid