Water purification

• What purification method is used in the video?

  Distillation
• What is the purpose of the distillation method shown?

  To purify seawater or sodium chloride solution
• What does the term "potable water" mean?

  Water that is safe to drink
• How is sodium tested in seawater?

  Using a flame test
• What color flame indicates the presence of sodium ions?

  Bright yellow flame
• What is the negatively charged ion found in seawater?

  Chloride ion
• How is chloride tested in seawater?

  Using a precipitation reaction
• What two chemicals are added to test for chloride ions?

  Nitric acid and silver nitrate
• What precipitate indicates the presence of chloride ions?

  White cloudy precipitate
• What happens to sodium and chloride ions during distillation?

  They remain in the flask
• What is the purpose of cooling the water vapor during distillation?

  To condense it back into liquid water
• What is the term for the water collected after distillation?

  Distillate
• Why is a clean nichrome wire used for the flame test after distillation?

  To avoid contamination from previous tests
• What result indicates that sodium ions are absent after distillation?

  No yellow flame observed
• What does a colorless solution indicate when testing for chloride ions after distillation?

  No chloride ions are present
• What are the steps involved in testing seawater for sodium and chloride ions?

  1. Test for sodium ions using a flame test.
  2. Test for chloride ions using precipitation.
  3. Distill the seawater.
  4. Retest for sodium and chloride ions in the distillate.
• What is the distillation process for purifying seawater?

  • Boil seawater to create water vapor.
  • Water vapor travels through a delivery tube.
  • Cool the vapor to condense it back into liquid.
  • Collect the distilled water in a container.
• What are the key observations during the tests for sodium and chloride ions?

  • Sodium: Bright yellow flame indicates presence.
  • Chloride: White precipitate forms with silver nitrate.
  • After distillation: No yellow flame or precipitate indicates absence.