Gas Tests

• What are the four carbon gases tested in the video?

  Chlorine, oxygen, hydrogen, and carbon dioxide
• What is the first step in testing for chlorine gas?

  Fill a test tube with the sample gas suspected to contain chlorine
• What happens to blue litmus paper when chlorine is present?

  It turns from blue to white
• Why might the blue litmus paper briefly turn red before turning white when testing for chlorine?

  Chlorine dissolves in water on the damp paper, forming hydrochloric acid
• What safety precautions should be taken when testing for chlorine?

  Wear a mask or conduct the experiment in a fume cupboard
• What is used to test for oxygen gas?

  A glowing splint
• What happens to a glowing splint when it is placed in oxygen?

  It relights
• What sound indicates the presence of hydrogen gas during testing?

  A squeaky pop
• What is the reaction that occurs when hydrogen burns in the presence of oxygen?

  It forms water
• What is used to test for carbon dioxide gas?

  An aqueous solution of calcium hydroxide (lime water)
• What happens when carbon dioxide is bubbled through lime water?

  The solution goes cloudy
• What are the tests for the four carbon gases and their results?

  • Chlorine: Turns damp blue litmus paper white
  • Oxygen: Relights a glowing splint
  • Hydrogen: Produces a squeaky pop with a lit splint
  • Carbon dioxide: Causes lime water to go cloudy
• Why does lime water go cloudy when carbon dioxide is present?

  Calcium carbonate is formed, which is a solid
• What is the final summary of the tests for the four gases?

  Chlorine turns paper white, oxygen relights splint, hydrogen makes a pop, carbon dioxide clouds lime water