....NOTE THAT...
^ MEANS Raise to power
/ means ÷ divide
* means multiplication sign .
+ means plus
= means equal to )
1)
TABULATE
Volume of pipette
Burette reading(cm3)|Rough titre(cm3)|First titre(cm3)|
Second titre(cm3)
Final reading(cm3)|20.00|19.60|19.60
Initial* some text missing *4^2-+16H^+->2NA^2++8H2O
+10CO2
1bi)
Conc of B in mol/dm3
CaVa/CbVb=Na/Nb
(0.05*19.6)/(Cb*25.0)=5/2
5*Cb*25=2*0.05*19.6
Cb=(2*0.05*19.6)/(5*25)=1.96
Cb=0.0157mol/dm3
Cb=0.016mol/dm3
1bii)
Conc in B in g/dm3
=0.0157*158
=2.4806g/dm3
=2.481g/dm3
2a)
Observation: C dissolved partially in solution
Inference:Salt C in a mixture of soluble and insoluble
2b)Observation:White precipitate is formed.White precipitate
dissolved in excess of NH3(aq), Inference:Cl^- is
present.Cl^- is confirmed
2ci)
Observation:Effervescence occur with liberation colourless
odourless gas which turn lime water milky
Inference:CO2(g) from HCO3^- or CO3^2-
2cii)
Observation:White precipitate is formed which is soluble in
excess,
Inference: Pb^2+,Zn^2+,Al^3+ may be present
2ciii)
Observation:white precipitate is formed which is soluble in
excess,
Inference:Zn^2+
3a)
i)Simple distillation-wide boiling point difference between constituent liquid
ii)Chromatography-Relative migration of constituents of mixture over an absorbent or rf-value difference of
constituents of mixture
iii)Fractional distillation-Close boiling point between constituent liquid
3b)
i)For easy identification of the end point ie the point of complete titration where the colour change is observed
ii)For accurate titre value ie to minimize the error margin
3c)
C1=2.5mol/dm3, V1=?,C2=0.20mol/dm3,V2=500cm3
C1V1=C2V2
V1=C2V2/C1
V1=(0.20*500)/2.5
V1=100/2.5
V1=40cm3
....keep refreshing...
Tags: waec chemistry practical runs, 2016 free waec chemistry practical runs, waec chemistry practical runs answer, 100% 2016 waec chemistry practical runs , 2016 waec chemistry practical runs, chemistry practical waec 2016 runs, waec 2016 waec chemistry practical runs, live 2016 waec chemistry answer now available, how to get 2016 waec chemistry question and answer, 2016/2017 waec chemistry question and answers. Download 2016 waec chemistry waec answer.. Waec chemistry, waec 2016 practical chemistry expo, waec chemistry runz/expo, 2016 waec chemistry practical runz now available, 2016 waec chemistry practical runz answer free anwers for chemistry practicals waec 2016/2017