Test for gases

• 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?


  You need a test tube full of the sample gas suspected to contain chlorine
• What happens to blue litmus paper when chlorine is present?


  The paper 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 precaution should be taken when testing for chlorine?


  Wear a mask or do it 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?


  The glowing splint will relight
• 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?


  Hydrogen and oxygen react to form 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
• Why does lime water go cloudy when carbon dioxide is present?


  Calcium carbonate is formed, which is a solid
• What are the tests for the four gases mentioned in the video?

  • Chlorine: Blue litmus paper turns white
  • Oxygen: Glowing splint relights
  • Hydrogen: Squeaky pop with a lit splint
  • Carbon dioxide: Lime water goes cloudy
• How does the test for chlorine differ from the test for oxygen?


  The chlorine test uses damp blue litmus paper, while the oxygen test uses a glowing splint
• What is the chemical reaction that occurs when carbon dioxide reacts with calcium hydroxide?


  Carbon dioxide reacts with calcium hydroxide to form calcium carbonate and water