water

• What is potable water?

  Potable water is safe to drink
• How does pure water differ from potable water?

  Pure water contains no dissolved solids, while potable water may contain them
• What is the pH of pure water?

  The pH of pure water is 7
• What does a pH not equal to 7 indicate about a water sample?

  It indicates that the water sample contains dissolved acid or alkali
• How can you check the pH of a water sample?

  By placing a small amount of the water onto universal indicator paper
• What should you do if the pH of the water sample is 7?

  You should still test for dissolved solids, as it may not be pure
• What is the first step in testing for dissolved solids in a water sample?

  Weigh an empty evaporating basin and record the mass
• What happens to the mass of the evaporating basin if the water sample contains dissolved solids?

  The mass will increase due to the formation of crystals on the basin
• What does it mean if the mass of the evaporating basin does not increase?

  It means the water sample did not contain any dissolved solids and could be pure
• What is one limitation of the practical regarding water purity testing?

  The practical does not investigate dissolved gases
• What is the purpose of distillation in purifying water?

  To separate water from dissolved solids and obtain pure water
• What equipment is used in the distillation process of water purification?

  A conical flask, delivery tube, and test tube
• What happens to water when it is heated during distillation?

  It evaporates and forms water vapor
• What occurs when water vapor enters the cold test tube during distillation?

  It condenses back into liquid water
• What is distilled water?

  Distilled water contains no dissolved solids and has a pH of 7
• What are the steps to analyze a sample of water for purity?

  1. Check the pH using universal indicator paper.
  2. Weigh an empty evaporating basin.
  3. Fill the basin with the water sample and evaporate the water.
  4. Weigh the basin again to check for dissolved solids.
  5. Note that dissolved gases are not tested in this practical.
• What is the process of purifying water by distillation?

  1. Heat the water sample in a conical flask.
  2. Water evaporates and forms vapor.
  3. Vapor travels through a delivery tube to a cold test tube.
  4. Vapor condenses back into liquid water.
  5. The result is distilled water, which is pure.