Past 2017 top best forum
Today's Date
Nigeria free 2018 Gallery
9ja NOTICE: You are currently viewing this website as a Guest and are restricted from viewing some vital information. For more permissions on Earlyface.com.ng? Like posting Comments, Topics and Uploading contents without Verification And Moderator's approval. Fast loading and quick accessibility. Registration is required. Please Login or Register now to gain full access. It is fast and free!!

CLICK HERE NOW TO BECOME EARLYFACE MEMBER...


Author Topic: CORRECT: 2016/2017 NECO Practical Chemistry Questions And Answers Expo/Runs free  (Read 4943 times)

0 Members and 1 Guest are viewing this topic.

Offline Uman

  • VIP MEMBER
  • Golden Member
  • *
  • Posts: 889
  • Vote for me: +421/-39
1)
volume of pipette used =25.0cm^3
indicator used =methyl orange
burette reading|rough| 21.50|0.00|21.50|
final burette readings (cm^3)|1st|21.20| 0.00. 21.20|
initial burette reading(cm^3)|2nd|31.20|10.00| 21.20|
volume of a used (cm^3)|3rd|41.20|20.00|21.20|
average volume of a used =(21.20+21.20+21.20)cm^3/3
=63.60cm^3/3
=21.20cm^3
equation of the reaction
H2SO4(aq)  + 2NaoH(aq)+2H2O(s)
nA=1,nB=2
A=4.90gldm^3 H2SO4
molar mass H2SO4
=(1*2)+32+(16*4)
=2+32+64
=98gmol^-1
molar conc A=mass con A/molar mass A
=4.90gldm^3/98glmol
=0.05moldm^3
CAVA/CBVB=nA/nB
0.05moldm^3*21.20cm^3/CB*25.0cm^3=1/2
0.05moldm^3*21.20*2=CB*25.0
CB=0.05molldm^3*21.20*2/25.0
CB=0.0848moldm^3
in mass conc B =Molar B*MolarBmass
B=NaoH
=23+16+1
=40gmol-^3
mass conc B =0.0848moldm^3 * 40gmol
mass con B = 3.392gldm^3
% mass of impusx 100%/total mass of implusty
mass of implus =(4.0-3.392)gldm^3
=0.608gldm^3
%impurity =0.608gldm^3*100%/4.0gldm^3
=15.2%

2ai)
Observation: The salt sample dissolves completely
Inference: C is a mixture of soluble salts

(2aii)
Observation: White precipitate insoluble in excess NaOH(aq)
Inference: Ca^2+ present

(2aiii)
Observation: No visible reaction
Inference: Ca^2+ is present

(2aiv)
Observation: Brownish fume is produced
Inference: NO2(g) form, NO3^- present

(2av)
Observation: Formation of brown gas which forms a ring junction with FeSO4
Inference: NO2 form, NO3^- confirmed

(2bi)
Observation: D dissolves completely. Formation of dirty green precipitate insoluble in excess NaOH(aq)
Inference: D is soluble in salt, Fe^2+ present

(2bii)
Observation: Formation of a white precipitate.precipi tate remains insoluble in HCl(aq)
Inference: SO3^2-,CO3^2-,SO4^2- present,SO4^2- confirmed

3ai)
Drawing lebel
-lid
-sticky tape(to hold paper)
-choroatographic paper
-gas jar
-applied spot of solute mixture
-ion
3aii)
principle of dillution, C1 V1=C2 V2
2.0molldm^3*40
3bi)
ethanol---->ethanoic (acid)---->trioxonotrate(v) (acid)
3bii)
indicators are used to determine the end point of the reaction and to test the acidity or alkalinity of a solution
   
To be getting all EarlyFace confirmed Updates (latest news in town, free browsing cheats, hottest FREEBIES, post-UTME tips, school matter and Exam stuff) for free through your Facebook and Twitter profile;
 
  • CLICK HERE to Like EARLYFACE on Facebook
  •  
  • CLICK HERE to Follow EARLYFACE on Twitter

  •    
    How To Create A Topic On Earlyface
     
    How To Create A Topic or Post On Earlyface as a Novice.

    Offline Godwin2016

    • Young Earlyfacian
    • Posts: 6
    • Vote for me: +1/-0
    • HomeTown: Makurdi
    We are waiting for d answers

    Offline Adeyemiii

    • Young Earlyfacian
    • Posts: 1
    • Vote for me: +0/-0
    • Location: K32 ilo Ilesha osun state nigeria
    • HomeTown: Ilesa

    Offline RAKABUBA2016

    • Flower Member
    • Posts: 11
    • Vote for me: +0/-0
    • Location: ADAMAWA
    • HomeTown: ADAMAWA STATE YOLA SOUTG
    i get only question one and it even came late. i could not write anything for today paper because of the delay you made which i cant predict the cause.
    i subscribe only with you.so i rely solely upon you.pls let us get the answers as early as you said--15mins after exam commenced.
    i wish you overcome the issues that cause you made delay today.
    i also wish you will respond to my complaint. thank you. RAKABUBA2016
    thanks-ibb

    Offline smith95

    • VIP MEMBER
    • Earlyface VIP
    • *
    • Posts: 4097
    • Vote for me: +57/-9
    • Location: NORTH BORDER
    • HomeTown: NORTH BORDER
    i get only question one and it even came late. i could not write anything for today paper because of the delay you made which i cant predict the cause.
    i subscribe only with you.so i rely solely upon you.pls let us get the answers as early as you said--15mins after exam commenced.
    i wish you overcome the issues that cause you made delay today.
    i also wish you will respond to my complaint. thank you. RAKABUBA2016
    we will.
       
    To be getting all EarlyFace confirmed Updates (latest news in town, free browsing cheats, hottest FREEBIES, post-UTME tips, school matter and Exam stuff) for free through your Facebook and Twitter profile;
     
  • CLICK HERE to Like EARLYFACE on Facebook
  •  
  • CLICK HERE to Follow EARLYFACE on Twitter

  •    
    How To Create A Topic On Earlyface
     
    How To Create A Topic or Post On Earlyface as a Novice.

     

    Related Topics


    Updated Topics

    CORRECT: 2024/2025 JAMB RUNS SUBSCRIPTION( REFORMED PACKAGES) by MANDINHO
    Yesterday at 09:04:51 am

    How to Create UNlimited GMAIL Account Without PHONE Number Verification by Wiz.gee
    Yesterday at 12:13:23 am

    UK FOOTBALL POOLS COUPON | 20TH APRIL 2024 | WEEK 42: X-02-X X-07-X X-15-X X-21- by wedco893
    April 14, 2024, 07:27:05 pm

    UK FOOTBALL POOLS COUPON | 13TH APRIL 2024 | WEEK 41: X-35-X by wedco893
    April 13, 2024, 05:10:53 pm

    CORRECT: 2024/2025 WAEC SSCE EXPO/RUNZ SUBSCRIPTION(MIDNIGHT DELIVERY) by MANDINHO
    April 12, 2024, 12:04:04 pm

    How to Create USA🇺🇲 TikTok Account that Can Earn You Money - Make Money on TikTok by Wiz.gee
    April 09, 2024, 04:52:42 pm

    Application Guide The Nigeria Immigration Service (NIS) has announced it 2024 Recruitment. Applications are hereby invit by afrocablenews2
    April 08, 2024, 01:32:07 am


    FBLike US on Facebook.. TWFollow US on Twitter..

    Portal
    Forum
    RSS Feeds
    FAQ
    Members Intro
    Announcements
    Privacy Policy
    Terms Of Use
    Partners
    About Us

    Problem Solutions
    Global News
    Sports
    Celebs
    Politics
    Gists In Town
    General
    Song Lyrics
    Dating
    Religion

    Examination
    Post-UTME/Admission
    School News
    Online Reading
    Scholarship
    Education
    Entertainment
    Download Links
    Stories
    Fashion

    MTN NG
    9Mobile NG
    Airtel NG
    Glo NG
    World Networks
    Pc Tweaks
    Mobile Phone
    Computer Tips
    WebMaster
    Programming

    Browsing Cheats
    Net Tricks
    Health n Welfare
    Latest Jobs
    EarlyFace Group Of Nigeria © 2022