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Chemical Tests - Coggle Diagram

- - - - Because the hydrogen gas reacts with the oxygen in the air and heat, forming a small explosion which is the squeaky pop
  - - - Because oxygen gas is a supporter in combustions, burning things
  - - - Because CO2 and limewater produces H2O along with Calcium Carbonate. It is a white precipitate so it makes the liquid look milky
  - - - Because the chlorine gas reacts with water and produces and acidic solution which makes the blue litmus paper turn red then bleach
  - - - Because ammonia is alkaline
- - - - 1) Add approximately 3 cm3 of a sulfate solution to the test-tube
      - 2) Add a few drops of hydrochloric acid*
        
        Solution needs to be acidified by dilute HCl first
      - 3) Add barium chloride solution drop-by-drop
      - 4) Note your observations
    - - Barium Sulfate → White precipitate
        
        sodium sulfate + barium chloride --> sodium chloride + barium sulfate
        
        Na2SO4(aq) + BaCl2(aq) --> BaSO4(s) + 2NACl(aq)
        
        SO4^-2 + Ba^2+ --> BaSO4(s)
  - - - 1) Add approximately 3 cm3 of chloride, bromide and iodide solutions to separate test-tubes
      - 2) Add a few drops of nitric acid*
        
        Nitric acid might react with other ions such as Carbonate ions and form precipitates
      - 3) Add silver nitrate solution drop-by-drop
      - 4)Note your observations
    - - Chloride → White precipitate
      - Bromide → Cream precipitate
      - Iodide → Yellow Precipitate
      - Equations: Halide ions + Silver nitrate --> Silver Halide
  - - - 1) Add approximately 3 cm3 of a carbonate solution to a test-tube
      - 2) Add a few drops of hydrochloric acid*
      - 3) Use a delivery tube to pass the gas produced through limewater
      - 4) Note your observations
    - - Carbonate → Lime water turns cloudy due to CO2 released
        
        CO3^2- + 2H^+ --> CO2 + H2O
- - - - Nichrome wire because it doesn't change the color of the flame when it burns
        
        hydrochloric acid cleans the wire because it converts the compound into metallic chloride which are much volatile
        
        Non-luminous flame because it is colorless and you can see the color change easily
    - - Must be into the flame. If you put it above the flame the flame would go up and follow the wire and it might burn you.
- - - - 1) Add approximately 3 cm3 of each solution to a test-tube
      - 2) Add sodium hydroxide solution slowly drop-by-drop
      - 4) Note your observations
      - 3) Continue adding sodium hydroxide until a large excess is present (when the test tube is about 2/3 full)
    - - Iron (II) Fe*2+ - Orange → Green (Iron II Hydroxide)
      - Iron (III) Fe*3+ - Clear yellow → Brown (Iron III Hydroxide)
      - Copper (II) Cu*2+ - Clear Blue green → Blue (Copper III Hydroxide)
      - Aluminum Al*3+ - Clear → milky white (Aluminum Hydroxide)
      - Calcium Ca*2+ - Clear → milky white (Calcium Hydroxide)
      - EQUATION: sodium hydroxide + metal salt --> metal hydroxide + sodium salt
  - - - 1) Add approximately 3 cm3 of the solution to a test-tube
      - 2) Add approximately 1 cm3 of sodium hydroxide solution slowly drop-by-drop
      - 3) Warm gently by placing the test tube in a water bath.
      - 4) After a short while, use tweezers to hold a piece of damp red litmus paper in the mouth of the test tube.*
      - 5)Note your observations
    - - Ammonium NH4+ --> Turns damp red litmus paper blue
- - - - Blue Copper Hydrated Sulfate ---> (heat up) White copper an-hydrated sulfate
      - CuSO4 + 5H2O(s) --> CuSO4(s) + 5H2O (l)
    - - White Copper an-hydrated Sulfate ---> (water) blue copper hydrated sulfate
      - CuSO4(s) + 5H2O(s) --> CuSO4(s) + 5H2O (s)
    - - 2H2 + O2 --> 2H2O
      - Hydrogen + Oxygen --> Water