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.

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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).

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.

Common misconception

Confusing the concentration and strength of acids.

Clearly define a strong and weak 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).

Lesson video

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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