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A large amount of aluminium sulfate was accidentally added to the drinking water supply at a water treatment works - AQA - GCSE Chemistry - Question 7 - 2019 - Paper 2
Question 7
A large amount of aluminium sulfate was accidentally added to the drinking water supply at a water treatment works. 07.1 Describe a test to show that the drinking w... show full transcript
Worked Solution & Example Answer:A large amount of aluminium sulfate was accidentally added to the drinking water supply at a water treatment works - AQA - GCSE Chemistry - Question 7 - 2019 - Paper 2
Step 1
Describe a test to show that the drinking water contained aluminium ions.
Answer
To test for the presence of aluminium ions, add a few drops of sodium hydroxide solution to a sample of the drinking water. If aluminium ions are present, a white precipitate will form. This precipitate may dissolve upon the addition of excess sodium hydroxide, confirming the presence of aluminium ions.
Step 2
Step 3
Plan an investigation to find the total mass of dissolved solids in a 100 cm³ sample of the drinking water.
Answer
To find the total mass of dissolved solids in the water sample, follow these steps:
- Weigh an empty evaporating basin.
- Measure 100 cm³ of the water sample and pour it into the evaporating basin.
- Heat the basin gently to evaporate the water completely.
- Once all the water has evaporated, allow the basin to cool and weigh it again.
- Subtract the mass of the empty basin from the mass of the basin with the dissolved solids to calculate the mass of the dissolved solids in the 100 cm³ sample.