Photo AI
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 aluminium ions in the drinking water, add a few drops of sodium hydroxide solution to a sample of the water.
If aluminium ions are present, a white precipitate will form. This precipitate is soluble in excess sodium hydroxide.
Step 2
Step 3
Step 4
Step 5
Plan an investigation to find the total mass of dissolved solids in a 100 cm³ sample of the drinking water.
Answer
To investigate the total mass of dissolved solids, follow these steps:
- Weigh an empty evaporating basin or dish to obtain its mass.
- Measure 100 cm³ of the drinking water and record its volume.
- Pour the water into the evaporating basin.
- Heat the basin gently to evaporate the water completely.
- Once the water has evaporated, allow the basin to cool.
- Weigh the basin again to obtain the mass after evaporation.
- Subtract the mass of the empty basin from the mass after evaporation to find the total mass of dissolved solids.
- Record your findings, ensuring to consider any potential sources of error.