WAEC 2023 - CHEMISTRY PRACTICAL  ANSWER



TAKE NOTE

For question 1

Use your school's endpoint and use it wherever you see our endpoint (15.15cm³) ...and calculate with it

Replace our 15.15 in 1b and do the calculation.

If your school wants to use mine, then the chemistry teacher must submit endpoint similar to ours without much difference...eg 15.15, 15.20, 15.30, etc
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(1)



TAKE NOTE
In 1ciii u will multiply 0.1 with ur school's average titre value(endpoint).
You can see that we used 15.15 which is our titre value.

If your school's endpoint is 12.50

Your calculation will be 0.1 x 12.50 / 1000
(1cii & 1ciii)


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(2)


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(3ai)
When drops of NaOH is added to 2cm^3 of Pb(NO3)2, a white gelatinous precipitate is formed, which is soluble in excess of it.

(3aii)
When drops of NaOH is added to 2cm^3 of Fe2(SO4)3, a reddish brown precipitate is formed, which is insoluble in excess of it.

(3b)
Put the benzoic acid crystals into a capillary tube fitted to a thermometer with rubber bands in an oil bath. Gently heat and stir until the crystals melt. Note the temperature. This is the melting point.