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    NOTE THAT ^ MEANS Raise to power.

    Draw Your Table As Usual And
    Input The Following:-

    Volume of pipette=25.00cm^3

    indicator used- Methyl orange colour

    change at end point-yellow to orange/purple

    Note Use Your School End Point.

     

    1)
    Tabulate
    Burette reading|Final burette reading(cm^3)|Initial burette reading (cm^3)| Volume of acid used(cm^3)|
    Rough- 24.10,0.00,24.10
    First- 23.80, 0.00, 23.80
    Second- 23.75, 0.00, 23.70
    Third- 23.75, 0.00, 23.75
    Average volume of A used = 23.80 + 23.70 + 23.75cm^3/3
    =23.75cm^3

    1bi)
    CAVA/CcVc=2/1
    Cc=CAVA/2VC
    =0.100*23.75Moldm^-3/2*25.00
    =0.0475moldm^-3
    amount of A used = 0.100x VA/1000=0.100*23.75/1000 =0.00237
    2moles Of A = 1mole of C
    0.002375mol of A = 0.002375mol/2
    100cm^3 of C contain 0.00237*100mol/2*25 =0
    1000cm3ofCcontained0.002375x1000mol
    2×25
    =0.0475mol
    concentration of C in moldm-3 =0.0475moldm-3

    1bii)
    Molar mass of Bing mol-1 br /> Molar mass of Na2CO3.yH2O=mass concentration of Bingdm-3
    molar concentration of Binmoldm-3
    =13.6gdm-3
    0.0475moldm-3
    =286gmol-1

    1biii)
    Molar mass of Na2CO3 =[(2×23)+12+(16×3)]=106gmol-1
    Mass of anhydrous Na2CO3=106×0.0475gdm-3
    =5.035gdm-3
    Mass of water=13.6-5.035gdm-3
    =8.565gdm-3
    Mass of Na2CO3 =Molar mass of Na2CO3
    Mass of water y×Molar mass of water
    5.035=106
    8.565 18y
    y =106×8.565
    5.035×18
    =10

    ==================================

    2a)
    Tabulate
    Test
    (i)Fn + H2O, then filter
    Observation
    White residue and blue filtrate was observed
    Inference
    Fn is a mixture of soluble and insoluble salts
    Test
    (ii)Filtrate + NaOH(aq) in drops, then in excess
    Observation
    A blue gelatinous precipitate which is insoluble in excess NaOH(aq) was formed
    Inference
    Cu2 + present
    Test
    (iii)Filtrate + NH3(aq) in drops, then in excess
    Observation
    A pale blue gelatinous precipitate was formed. The precipitate dissolves or is soluble in excess NH3(aq) to give a deep blue solution
    Inference
    Cu2+ confirmed
    Test
    (iv)Filtrate + dil.HNO3 +AgNO3(aq)
    Observation
    No visible reaction White precipitate formed
    Inference
    Cl- present
    Test
    +NH3(aq) in excess
    Observation
    Precipitate dissolved in excess NH3(aq)
    Inference
    Cl- confirmed
    2bi)First portion of residue +NaOH(aq) in drops, then in excess
    Observation
    White powdery precipitate which is insoluble in excess NaOH(aq)
    Inference
    Ca2+ present
    Test
    2bii)Second portion of residue + dil.HCl
    Observation
    Effervescence/bubbles; colourless, odourless gas evolved.
    Gas turns lime water milky and turns damp blue litmus paper red.
    Inference
    Gas is CO2
    CO3^2- or HCO3- present

    ====================

    3i) Lime juice is cacitic in nature and the color of methyl orange in active medium is Red
    3ii) Iron
    (iii)chloride will be reduced to iron
    (ii) with the yellow deposit of Sulphur
    3iv)Addition of ethanoic acid to k2lo3 results to the liberation of a colourless or odourless gas co2 Which turns lime water milky

    ====COMPLETED====
    BEST OF LUCK

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    Master Solution April 11, 2017 Categories: WAEC 976


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    2 Comments

    1. Onyi says:
      April 11, 2017 at 1:50 pm

      Reason I love this site is bcoz they always deliver on time

      Reply
    2. Kingsley says:
      April 3, 2017 at 2:28 pm

      This practical was nothing FOr me ,, I studied all the questions and answers u sent me at night

      Reply
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