This question is about salts - AQA - GCSE Chemistry Combined Science - Question 2 - 2019 - Paper 1
Question 2
This question is about salts.
Ammonium nitrate solution is produced when ammonia gas reacts with nitric acid.
1. Give the state symbol for ammonium nitrate.
2. Wh... show full transcript
Worked Solution & Example Answer:This question is about salts - AQA - GCSE Chemistry Combined Science - Question 2 - 2019 - Paper 1
Step 1
1. Give the state symbol for ammonium nitrate.
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Answer
The state symbol for ammonium nitrate is (aq), indicating that it is an aqueous solution.
Step 2
2. What is the formula of nitric acid?
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Answer
The formula of nitric acid is HNO₃.
Step 3
3. What colour is observed in each solution?
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Answer
In nitric acid, the universal indicator shows a red colour indicating it's acidic. In ammonia solution, the colour is typically blue, indicating it's basic.
Step 4
4. Which row shows the change in pH?
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Row D shows the change in pH as the nitric acid is added: initially 10 and after addition of excess nitric acid, it drops to 2.
Step 5
5. Calculate the percentage by mass of oxygen in ammonium nitrate (NH₄NO₃).
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Answer
The relative formula mass of NH₄NO₃ is calculated as follows:
Mass of oxygen: 3 × 16 = 48
Total mass of NH₄NO₃: 80
Percentage by mass of oxygen = (48 / 80) × 100 = 60%. Therefore, the percentage by mass of oxygen is 60%.
Step 6
6. Describe a method to investigate how the temperature changes.
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To investigate the temperature change when dissolving ammonium nitrate:
Use a suitable container such as a test tube.
Add a known mass of ammonium nitrate to the test tube.
Add a measured volume of water.
Record the initial water temperature using a thermometer.
Stir to dissolve the solid completely.
Measure the final temperature once the solid has dissolved.
Calculate the temperature change by finding the difference between initial and final temperatures.
Repeat the experiment with varying masses of ammonium nitrate and conduct the measurements again.
