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This question is about carboxylic acids - AQA - GCSE Chemistry - Question 7 - 2020 - Paper 2
Question 7
This question is about carboxylic acids. Carboxylic acids belong to a homologous series. Table 3 shows information about the first three carboxylic acids in this ho... show full transcript
Worked Solution & Example Answer:This question is about carboxylic acids - AQA - GCSE Chemistry - Question 7 - 2020 - Paper 2
Step 2
Explain how the equation shows that ethanoic acid is a weak acid.
Answer
The equation shows that ethanoic acid ionizes partially in water, yielding both the acetate ion (CH₃COO⁻) and hydrogen ions (H⁺). This reversibility indicates that the reaction does not go to completion, meaning not all CH₃COOH molecules will dissociate. Therefore, ethanoic acid is classified as a weak acid.
Step 3
Explain what happens to the mass of the flask and its contents during the reaction.
Answer
During the reaction between ethanoic acid and zinc carbonate, carbon dioxide (CO₂) gas is produced. As the gas escapes from the flask, the mass of the flask and its contents will decrease. The decrease corresponds to the amount of CO₂ that has left the system.
Step 4
Explain why.
Answer
The reaction rate with methanoic acid is greater than that with ethanoic acid because methanoic acid has a lower pH, indicating a higher concentration of H⁺ ions in a 0.01 mol/dm³ solution. This increases the frequency of effective collisions between the acid and zinc carbonate, leading to a faster reaction.
Step 5
Step 6