Education

Waec 2017 Chemistry (Practical Alternative A) Question & Answers

Loading...

Waec 2017
Chemistry (Practical
Alternative A)
Answers – May/
June Expo

 

================================
NOTE THAT ^ MEANS Raise to
power.
Pls 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.
Tabulate
================================
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:
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

================================
(2)Tabulate
Test
(a)(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
Precipitatedissolvedin

excessNH3(aq)

Inference
Cl-confirmed

 

 

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

 

If you want us to post more answers keep inviting your friends to this website (Yoloaded.com), you know that we use to post answer answer in time ….. So tell ur friends or no more.

26 Comments

26 Comments

  1. Samsonteno

    April 10, 2017 at 5:55 pm

    Yes I Need It

  2. Damilola

    April 10, 2017 at 6:21 pm

    I like d way u post bcuz u dnt want student to fail.And God will reward u in all wat u are doing.

  3. Kelvin

    April 10, 2017 at 9:53 pm

    I want answer

  4. blessing

    April 10, 2017 at 10:21 pm

    yes i need it

  5. Michael

    April 11, 2017 at 6:43 am

    I need your help on my chemistry practical

  6. Niniola

    April 11, 2017 at 7:08 am

    Yes I need it

  7. Rasheed asamu

    April 11, 2017 at 7:10 am

    We thanks you, for your help given to us God shall conque all what you are desire may all your difficulties will be a way to your success

  8. Arahman

    April 11, 2017 at 7:36 am

    I very appreciate what u did in physics plz we need chem practical

  9. alpha

    April 11, 2017 at 7:47 am

    Pls we love it and we need it

  10. Mohamnzxy

    April 11, 2017 at 7:55 am

    I love your post, please post it at early..

  11. tosky

    April 11, 2017 at 8:10 am

    I N

  12. Fetus

    April 11, 2017 at 8:13 am

    I need chemistry

  13. muis

    April 11, 2017 at 8:30 am

    Pls I need d answer

  14. phork stunner

    April 11, 2017 at 9:05 am

    pls we need chemistry now

  15. mistafegge

    April 11, 2017 at 9:32 am

    Pls I need government answer as early possible by tomorrow

  16. Anonymous

    April 11, 2017 at 9:33 am

    Cute

  17. Abidex

    April 11, 2017 at 9:34 am

    Cute

  18. Benjamin

    April 11, 2017 at 10:07 am

    I need chemistry group A correct answers

  19. Samuel

    April 11, 2017 at 10:15 am

    We love it

  20. Benjamin

    April 11, 2017 at 10:30 am

    Very happy i appreciate

  21. Emma

    April 11, 2017 at 11:00 am

    I love yo loaded

  22. #smith

    April 11, 2017 at 11:18 am

    Tenkz bro! For 🎭 the chemistry practical.

  23. Degame

    April 11, 2017 at 11:48 am

    I nid govt thank u

  24. Dave godwin

    April 11, 2017 at 2:23 pm

    I really appreciate u all.. pls i need government answers

  25. mike

    April 11, 2017 at 3:14 pm

    i need it

  26. Chris

    April 11, 2017 at 3:39 pm

    I love this site keep it up

Leave a Reply

Your email address will not be published.

Most Popular

To Top