This question is about salts - AQA - GCSE Chemistry Combined Science - Question 1 - 2022 - Paper 1
Question 1
This question is about salts.
Green copper carbonate and sulfuric acid can be used to produce blue copper sulfate crystals.
Excess copper carbonate is added to sul... show full transcript
Worked Solution & Example Answer:This question is about salts - AQA - GCSE Chemistry Combined Science - Question 1 - 2022 - Paper 1
Step 1
Excess copper carbonate observations
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Answer
The green solid (copper carbonate) will start to fizz as it reacts with sulfuric acid, producing gas bubbles.
A blue solution (copper sulfate) will begin to form, indicating the reaction is occurring.
Eventually, the green solid will disappear completely, leaving a clear blue solution.
Step 2
How can the excess copper carbonate be removed?
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The excess copper carbonate can be removed by filtration. The solid residue will be trapped on the filter paper while the blue copper sulfate solution passes through.
Step 3
What is the pH of the solution at the end of the reaction?
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The pH of the solution at the end of the reaction is 7, indicating that the solution is neutral.
Step 4
What type of reaction is this?
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This reaction is a neutralization reaction, as an acid (sulfuric acid) reacts with a carbonate (copper carbonate) to produce a salt (copper sulfate), water, and carbon dioxide.
Step 5
Determine the mass of ammonium nitrate that crystallizes
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At 80 °C, the maximum mass of ammonium nitrate that can dissolve in 100 cm³ of water is 83 g. At 20 °C, this value is 32 g. Therefore, the mass that crystallizes is:
83extg−32extg=51extg
So, the mass of ammonium nitrate that crystallizes on cooling 100 cm³ of the solution from 80 °C to 20 °C is 51 g.
