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This question is about reactions of ethanoic acid and the analysis of salts - AQA - GCSE Chemistry - Question 1 - 2016 - Paper 3
Question 1
This question is about reactions of ethanoic acid and the analysis of salts. 1 (a) Figure 1 shows the apparatus used to investigate the reaction of ethanoic acid wi... show full transcript
Worked Solution & Example Answer:This question is about reactions of ethanoic acid and the analysis of salts - AQA - GCSE Chemistry - Question 1 - 2016 - Paper 3
Step 1
Describe a change that would be seen in each test tube.
Answer
In Test tube 1, there would be fizzing or effervescence due to the release of gas as ethanoic acid reacts with calcium carbonate. The limewater will turn cloudy because of the formation of calcium carbonate from the carbon dioxide produced.
In Test tube 2, no observable change would occur since it only contains limewater without any reaction with ethanoic acid.
Step 2
Give a reason for each change.
Answer
The fizzing in Test tube 1 is caused by carbon dioxide gas being released during the reaction. The cloudiness observed in the limewater is due to the precipitation of calcium carbonate.
No change in Test tube 2 occurs because there is no reactant to drive a chemical reaction.
Step 3
Step 4
Step 5
Complete the table of results.
Answer
| Solution | Test with silver nitrate in the presence of dilute nitric acid | Test with barium chloride in the presence of dilute hydrochloric acid | |-----------------------------|---------------------------------------------------------------|===================================================================| | Potassium chloride solution | no change | no change | | Calcium nitrate solution | no change | white precipitate | | Ammonium sulfate solution | no change | no change | | Water | no change | no change |
Step 6
Step 7
Give one reason why a flame test would not show the presence of both potassium ions and calcium ions in a mixture.
Answer
A flame test would not show the presence of both potassium ions and calcium ions because the colours are masked or changed by each flame colour. The strongest colour might dominate the observed flame.