CHEMISTRY PRACTICAL ANSWERS

1a)
Burette Reading –> Before Boiling –> After Boiling
Final Readings(cm^3) –> 27.00 –> 13.00
Initial Reading(cm^3) –> 0.00 –> 4.00
Volume of acide used –> 27.00 –> 9.00

1ai)
I – it is Burette
II – It is Pipette
1aii)
there is formation of lethal at the end points that is why separate indicator is not needed for the titration excercise

1aiii)
volume of temporary hardness = 9.00cm^3
volume of permanent hardness
= 27 – 9 = 18.00cm^3
1aiv)
Ratio of temporary to permanent hardness = 9:18

1bi)
The Equation for the reaction is
2NaoH(aq) + H2So4(aq) ———-> NaSo4(aq) + H2O(l)
Na = 1, Ca = 0.245, Va = 19.50cm^3
Nb = 2, Cb = ?, Vb = 25.00cm^3
CaVa/CbVb = Na/Nb = 0.245 x 19.50/Cb x 25 = 1/2
Cb = 9.555/25
=0.352mol/dm^3

1bii)
Conc. Mol/dm^3 = Conc. g/dm^3/Molar Mars
Molar Mass of NaoH = (23 + 16 + 1) = 40
(g/mole)
Conc. g/dm^3 = 40 x 0.382 = 15.3g/dm^3
Mass of Pure = 15.3g/dm^3
Mass of impure = 1000 x 10/500 = 20g/dm^3
Percentage Purity = pure/impure x 100% = 15.3/20 x 100
= 76.5%

1c)
It is sodium chloride(Nacl)
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Tabulate
Test applied.|observation

2ai)
Portion+Litmus paper| ethanoic acid turns blue litmus paper orange | glucose solution. It has no effect on litmus paper| liquid ethanol. It has no effect on litmus paper

2aii)
Portion+NaHco3 |co2 oxide is evolved with brisk effeve sence| it dissolves without any visible reaction| NCo reaction is noticed

2aiii)
Portion+acidified Km10O4 solution| ethanol does nt give any reaction| it changes form to colourless| it is oxidized to ethanoic acid

2bi)
Brown ring test
To the agreed solution,add small quantity of dilute H2SO4,then freshly prepare iron it tetraoxosulphate (iv) and conc.H2SO4 and shake rigourously and thenslant the tube a brown ring shows the presense of NO3^2-

2bii)
A reddish brown precipitate is produced
A brownish gas is evolved.

2ci)
X-it is a refort stand
Y-it is a funnel
Z-it is an aspirator
2cii)
U_tube:
it changes to blue because of
the presence of water vapour.
Conical flask:
it turns lime water milky
The products are carbon(iv)oxide and carbon(II)oxide

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3ai)
Add water to the mixture,then filter off the sugar solution,the sugar solution is then placed on the water bath to drain off the water until the crystals of sugar start showing i.e a saturated solution.
It is then allow to cool as to obtain pure crystal of sugar.

3aii)
The melting point of surgar

3bi)
Chlorine gas is generally prepared in a fume cupboard because it has choking smell.

3bii)
A LE is due to the fact that oxygen is less dease than air.

3biii)
It is due to the presence of Ultra violet rays or sunlight.

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