AQA GCSE FOUNDATION Chemistry: Water Purification

AQA GCSE Foundation Chemistry: Water Purification

This tutorial will guide you through the process of testing water purity using filtration and distillation. By the end, you'll understand how these methods work and their relevance to real-world water purification techniques.

Materials:

• Tap water
• Salt
• Beaker
• Funnel
• Filter paper
• Bunsen burner
• Tripod
• Heat-resistant mat
• Conical flask
• Delivery tube
• Test tube
• Dropper

Procedure:

1. Prepare the solution:
   • Add a spoonful of salt to a beaker of tap water. Stir until the salt dissolves.
   • This solution represents contaminated water.
2. Filtration:
   • Fold the filter paper and place it in the funnel.
   • Pour the salty water through the filter paper.
   • Observe the filtrate (the liquid collected in the beaker below).
   • Analysis: The filtrate will still be cloudy, indicating that filtration alone cannot remove dissolved solids.
3. Distillation:
   • Set up the distillation apparatus.
   • Pour the filtrate into the conical flask.
   • Heat the flask using the Bunsen burner.
   • As the water boils, the steam rises and travels through the delivery tube.
   • The steam condenses back into liquid (distillate) in the test tube.
   • Analysis: The distillate should be clear and pure, indicating that distillation successfully removes dissolved solids.
4. Testing for purity:
   • Compare the taste and appearance of the original solution, the filtrate, and the distillate.
   • This will confirm that distillation produces purer water.

Observations:

• Filtration removes visible solid particles but not dissolved substances.
• Distillation separates water from dissolved impurities, resulting in pure water.

Real-world Applications:

• Filtration: Used in water treatment plants to remove larger particles. Sand filtration is commonly employed.
• Distillation: Used in desalination plants to produce fresh water from seawater.

Conclusion:

Filtration and distillation are essential methods for purifying water. They work by separating different components of water based on their physical properties. Understanding these methods helps us appreciate the complex processes involved in providing safe and clean drinking water.