Skip to content
Dabour HubLEARN · PRACTICE · EXPLORESign inStudent

4.7.1Electrochemistry

Esters — Cambridge IGCSE Chemistry 0620 Revision Notes & Topical Questions

5 min read 5 parts Lesson 13 of 20 Unit quiz

📚 Cambridge IGCSE Chemistry 0620 Hub / Topical Revision
🩺
100% Curriculum Specification Match Lesson Doctor Verified
The only platform with 100% curriculum specification match and verified interactive question banks.
Curriculum Equation Key معادلة تفاعل تكوين الإستر (الأسترة) - Esterification Reaction EquationFast Exam Solution
R-COOH + R2-OH ⇌ (conc. H₂SO₄) R-COO-R2 + H₂O
Word Equation & Conditions: حمض كربوكسيلي + كحول (في وجود حمض الكبريتيك المركز كعامل حفاز ونازع للماء) ⇌ إستر + ماء
Location & Specifications: الكيمياء العضوية للثانوية العامة والتحصيلي و Edexcel Chemistry.
0%read

Part 1 of 5Esterification

Formation
  • Formation Esters form when an alcohol and a carboxylic acid react, with concentrated sulfuric acid as the catalyst.
Ester link
  • Ester link Esters contain the –COO– functional group, which links two carbon chains and is written as R–COO–R′.
Water
  • Water One molecule of water is produced in each esterification, as the –OH of the acid combines with an H from the alcohol.
Reversible
  • Reversible Esterification is reversible, so the reverse reaction can break the ester back down into acid and alcohol.
Smell
  • Smell Esters are sweet-smelling oily liquids, which is why they are used in food flavourings and perfumes.

Part 2 of 5Naming and Structure

1
The alcohol part gives the first word of the name, ending in -yl, such as propyl from propanol.
2
The carboxylic acid part gives the second word, ending in -oate, such as ethanoate from ethanoic acid.
3
Propanol and ethanoic acid therefore form propyl ethanoate, CH₃COOCH₂CH₂CH₃.
4
The ester link –COO– joins the carbon of the acid part to the oxygen of the alcohol part.

Part 3 of 5Examples of Esters

Examples of Esters
Naming
  • Naming Ester names give the alcohol part first, ending in -yl, and then the acid part, ending in -oate.
Scent
  • Scent Many esters have fruity smells, which is why they are used in flavourings and perfumes.
Volatility
  • Volatility Esters have low boiling points, so they evaporate easily from a reaction mixture.
AlcoholCarboxylic acidEster formed
EthanolEthanoic acidEthyl ethanoate, CH₃COOC₂H₅
PropanolEthanoic acidPropyl ethanoate, CH₃COOCH₂CH₂CH₃
PentanolButanoic acidPentyl butanoate, CH₃CH₂CH₂COOC₅H₁₁

Part 4 of 5Worked Example

Question Name the ester formed from methanol and butanoic acid, and give its molecular formula.

  1. Methanol gives the first word, methyl, and butanoic acid gives butanoate
  2. The ester is methyl butanoate, CH₃CH₂CH₂COOCH₃
  3. Count the atoms5 carbon, 10 hydrogen and 2 oxygen

Answer Methyl butanoate, CH₃CH₂CH₂COOCH₃, with molecular formula C₅H₁₀O₂.

Part 5 of 5Exam Checklist & Tips

4.7.1 – Key Points for the Exam

  • Ester An organic compound containing the –COO– functional group, formed from an alcohol and a carboxylic acid.
  • Esterification The reaction between an alcohol and a carboxylic acid to form an ester and water.
  • Ester link The –COO– group that joins the two parts of an ester.
  • Concentrated sulfuric acid The catalyst used in esterification.
  • Volatile Easily evaporated, as esters are because of their low boiling points.

Common Mistakes

  • Naming esters with -ol and -oic acid endings; esters end in -yl and -oate.
  • Forgetting that the water formed comes from the –OH of the acid and an H from the alcohol.
  • Writing the ester link as –CO– instead of –COO–, which leaves out an oxygen atom.
  • Using the alkane name, such as methane, for the alcohol part of an ester name, when -yl is needed.

Last updated:

\n