New
New
Year 11
OCR
Higher

Carboxylic acids and esters

I can describe the structure of the first four carboxylic acids, and recognise and describe reactions where carboxylic acids are involved.

New
New
Year 11
OCR
Higher

Carboxylic acids and esters

I can describe the structure of the first four carboxylic acids, and recognise and describe reactions where carboxylic acids are involved.

Lesson details

Key learning points

  1. Carboxylic acids have a -COOH functional group.
  2. Carboxylic acids are weak acids.
  3. When ethanol is oxidised, ethanoic acid is formed.
  4. Carboxylic acids react with carbonates to produce a metal salt, carbon dioxide and water.
  5. Carboxylic acid can react with alcohol to produce esters (such as ethyl ethanoate).

Common misconception

Confusing the concentration and strength of acids.

Clearly define a strong and weak acid.

Keywords

  • Carboxylic acids - Carboxylic acids are a homologous series of compounds that contain the -COOH functional group.

  • Weak acids - Weak acids partially dissociate to form Hᐩ ions in solution.

  • Carbonate - A carbonate is a compound containing the CO₃²ᐨ ion. An example is calcium carbonate CaCO₃.

  • Esters - Esters are a homologous series of compounds that contain the -COO- functional group.

  • Ethyl ethanoate - Ethyl ethanoate is an ester produced from the alcohol ethanol and the carboxylic acid ethanoic acid.

Practical task opportunities - test the pH of carboxylic acids, react them with metal carbonates and produce esters.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
Match the homologous series of compounds with the correct functional group.
Correct Answer:alkene,C=C

C=C

Correct Answer:alcohol,OH

OH

Correct Answer:carboxylic acid,COOH

COOH

Q2.
What is the name of the carboxylic acid in the image?
An image in a quiz
butanoic acid
Correct answer: ethanoic acid
propanoic acid
methanoic acid
Q3.
Order the carboxylic acids by increasing chain length starting with the shortest carboxylic acid.
1 - methanoic acid
2 - ethanoic acid
3 - propanoic acid
4 - butanoic acid
5 - pentanoic acid
Q4.
What is produced when an alcohol is oxidised using an oxidising agent?
alkane
alkene
alcohol
Correct answer: carboxylic acid
ester
Q5.
What are the products from reactions between acids and metal carbonates?
salt + carbon dioxide
salt + water
salt + hydrogen
salt + hydrogen + water
Correct answer: salt + carbon dioxide + water
Q6.
Which of the following statements about weak acids are true?
Correct answer: partially dissociate to produce H⁺ ions in solution
fully dissociate to produce H⁺ ions in solution
have a pH of 1
form a blue or purple colour with universal indicator solution
Correct answer: form an orange, yellow or pale green colour with universal indicator solution

6 Questions

Q1.
Name the molecule shown in the image.
An image in a quiz
Correct Answer: ethanoic acid
Q2.
Which functional group do esters contain?
C=C
-OH
COOH
Correct answer: -COO-
Q3.
Where are esters used?
Correct answer: in perfumes
as fuels
Correct answer: as flavourings
in alcoholic drinks
Q4.
Match the key term with the correct definition
Correct Answer:carboxylic acids,A homologous series of compounds containing the -COOH functional group

A homologous series of compounds containing the -COOH functional group

Correct Answer:weak acids,Partially dissociate to form Hᐩ ions in solution

Partially dissociate to form Hᐩ ions in solution

Correct Answer:carbonate,A compound containing the CO₃²ᐨ ion.

A compound containing the CO₃²ᐨ ion.

Correct Answer:esters,A homologous series of compounds containing the -COO- functional group

A homologous series of compounds containing the -COO- functional group

Q5.
What are the products when a metal carbonate reacts with a carboxylic acid?
Correct answer: metal salt
hydrogen
Correct answer: water
Correct answer: carbon dioxide
oxygen
Q6.
Which two reactants can react together to form the ester ethyl ethanoate?
methanol
Correct answer: ethanol
methanoic acid
Correct answer: ethanoic acid
ethane