Term 1 Lab Lessons

Below are my reflections of my Term 1 Lab sessions:

• 2P01: Properties of Acids and Alkalis
  
  
  This is the first lab experiment of the year and it is related to properties of Acids and Alkalis.
  
  
  The aim of it is to find the properties of acids, bases and neutral solutions.
  
  
  In this experiment we are suppose to test the PH level of 6 aqueous solution A, B, C, D, E, F.
  
  
  In order to check whether the solution conducts electricity we also used the Electrical conductivity tester.
  
  
  However, for the PH of the solution, we used 4 different types of indicator: Universal Indicator, Methyl Orange, Phenolphtalein and Litmus paper.
  
  
  I won't be including my observations of the experiment in my reflection, rather I will say what I have learn.
  
  
  
  
  pH at which pH indicator changes colour:
  
  
  
  
  METHYL ORANGE:
  
  
  pH--> 0-4 ---- Red ( Strong Acid)
  
  
  pH--> 4-14 --- Yellow (Weak acid + Base)
  
  
  
  
  Conclusion: It is only appropriate for testing of Strong Acids.
  
  
  
  
  PHENOLPHTHALEIN:
  
  
  pH--> 0-9 --- Colourless (Acid + Weak bases)
  
  
  pH--> 9-14 --- Red (Strong Bases)
  
  
  Conclusion: It is only apt to use this for the identification of Strong Bases.
  
  
  
  
  LITMUS PAPER:
  
  
  pH--> 0-6 --- Red (Acids)
  
  
  pH--> 8-14 --- Blue (Bases)
  
  
  
  
  Conclusion: Just a vague indicator of Acids and Bases not appropriate to test for Strong Acids or Bases.
  
  
  
  
  UNIVERSAL INDICATOR:
  
  
  
  
  
  
  
  The pH Colour change is shown as above.
  
  
  
  
  
  
  Conclusion:
  
  
  Universal Indicator as its name suggest is Universal. It is very versatile in identification of Strong acids, Weak acids, Strong bases and Weak bases. It is widely used because of its versatile identification of Acids and Bases.
  
  

  
  

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  2P02: When Dilute Acid Meets Metals

  
  

  The Aim of this experiment is to investigate the action of dilute acids on Metals.

  
  

  Dilute HCl come in contact with 4 Metals(Magnesium, Zinc powder, Iron fillings and Copper turnings).

  
  

  
  

  Dilutes acids react with each of the metals above to produce Hydrogen(g) and Salt.

  
  

  
  

  The General reaction is as follows:

  
  

  
  

    Acid + Metal --> Salt + Hydrogen

  
  

  
  

  In order to test whether Hydrogen gas is really produced, we lighted a splint and inset it into the test tube and if a 'pop' sound is heard there is indeed Hydrogen. But this must be done as fast as possible in order before the Hydrogen gas escaped.

  
  

  
  

  In this lesson, we also learn how to write word equations.

  
  

  
  

  
  

  EXTRA:

  
  

  
  

  Reactivity Series (For Acid):

  
  

  
  
  
  

  
  

  Hydrogen is used as a benchmark. Anything below Hydrogen have little or no reactions with Acid.

  
  

  
  

  
  

  Extra Notes:

  
  

  A catalyst is used to lower the energy required to react the solution.

  
  

  
  

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  • 2P03: When Dilute Acid Meets Carbonates

  
  

  
  

  Aim: To investigate the action of dilute acids on Carbonates.

  
  

  Dilute acids react with a carbonate to produce salt, water and carbon dioxide gas.

  
  

  
  

  Word equation:

  
  

     Acid + Carbonate --> Salt + Water + Carbon Dioxide

  
  

  
  

  Notes:

  
  

  1) Carbon dioxide is acidic in nature.

  
  

  2) To test for the presence of Carbon Dioxide, pass the produced gas through lime water (Calcium Hydroxide). Carbon dioxide will react with Calcium Hydroxide to produce an insoluble product (Calcium carbonate and water).

  
  

  
  

  
  

  In this lab session we also learn how to write Word equation and learn to balance Chemical Equations.
  
  

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  2P04: When Acid Meets Alkali
  
  Notes:
  
  1) Ethanoic acid is CH3COOH and it is also called Acetic acid.
  
  
  Extra:
  
  5 general Rules of Solubility of Salts
  
  1) All Chlorides are soluble except Silver Chloride(II) & Lead(II) Chloride.
  
  2) All Sulphates are soluble except Silver sulphate, Barium sulfate, Lead(II) sulphate & Calcium sulphate.
  
  3) All Nitrates are soluble.
  
  4) All Carbonates are insoluble except Group I Carbonates and Ammonium Carbonate.
  
  5) All hydroxides are insoluble except Group I hydroxides, Ammonium hydroxide and Barium hydroxide.