Learning focus
Develop accurate organic nomenclature, connect functional groups to reactions, draw structural and polymer formulae, interpret industrial processes and apply evidence to unfamiliar compounds.
Formula pattern
An ester can be represented as RCOOR. The carbonyl-side group comes from the acid, while the group attached after oxygen comes from the alcohol.
From reactants to structure
For methanol + propanoic acid, write CH3CH2COOCH3 and name methyl propanoate. For propan-1-ol + methanoic acid, write HCOOCH2CH2CH3 and name propyl methanoate.
From name to formula
Split methyl ethanoate into methyl and ethanoate. Draw CH3COO- for ethanoate and attach CH3 after the single-bond oxygen, giving CH3COOCH3.
Valency check
The carbonyl carbon has a double bond to one oxygen and a single bond to the second oxygen. The second oxygen has two single bonds. Every carbon has four total bonds.
High-value recall and connections
Essential recall: Name CH3CH2COOCH3. Methyl propanoate. Write ethyl methanoate. HCOOCH2CH3. What linkage is present? -COO-. Practical connection: Generate a grid of alcohols and acids up to four carbons and name selected ester products without memorising them individually. Examination connection: Do not reverse the two name parts: the alkyl group attached to oxygen is named first.
Practical or data skill
Generate a grid of alcohols and acids up to four carbons and name selected ester products without memorising them individually.
Examination tip
Do not reverse the two name parts: the alkyl group attached to oxygen is named first.
Review questions and suggested answers
Question 1
Name CH3CH2COOCH3.
Suggested answer
Methyl propanoate.
Question 2
Write ethyl methanoate.
Suggested answer
HCOOCH2CH3.
Question 3
What linkage is present?
Suggested answer
-COO-.
