Chemistry Paper 1 (Practical) ,May/June 2011  
Questions:       1 2 3 4 5 6   Main
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Question 3
  1. A colourless gas P was given off when dilute tetraoxosulphate (VI) acid was added to zinc salt Q.  On bubbling the gas through lime water, a white precipitate R was formed.  Identify P, Q and R.                                                
  2. Name a suitable apparatus that could be used to perform each of the following activities in   the laboratory:
    i. storage of dilute silver trioxonitrate (V);
    ii. heating copper metal;
    iii. separation of a mixture of water and kerosine.
    Give one reason for each of your answers in (b).

    Most candidates were unable to make precise statements.  Most candidates correctly identifiedPas CO2 and R as CaCO3 but could not identify Q as ZnCO3.  Most candidates could neither name nor give correct reason for a suitalbe apparatus for:
  1. storing of dilute silver trioxonitrate (V);
  2. heating copper metal.



Many candidates however, correctly named the separating funnel and gave correct reason for using it.

    The expected answers are:
  1. P – CO2 or Carbon(IV) oxide
  2. Q - ZnCO3 or Zinc trioxocarbonate (IV)
    R – CaCO3  or calcium trioxocarbonate (IV)

  1. (i)         -  dark brown/amber coloured bottle
  2. (ii)        -  bunsen burner
    (iii)       -  separating funnel

  1. Amber coloured bottle reduces the intensity of/prevents light entering the bottle to decompose Ag NO­3.
  2. Bunsen burner produces high intensity of heat/tempearture
  3. Because water and kerosene are not miscible/due to immiscibility of water and kerosene.


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