NECO Chemistry Practical Questions and Answer Solution – May/June 2017 Expo Runz
NO1)
Note:
Candidates are strongly advised to check which size of pipette was used by their school.
We used 25cm³
—————————
If your school used 20cm³, all you need do is use it in place of 25cm³ anywhere we used it and calculate accordingly
NOTE:ALL MAKE USE OF YOUR SCHOOL ENDS POINT
Volume of Pipette used 25.0cm^3
Titration | Rough | First | Second | Third
Final burette reading (cm^3) | 22.50 | 45.10 | 32.65 | 27.60
Intial burette reading (cm^3) | 0.00 | 22.50 | 10.00 | 5.00
Volume of A used (cm^3) | 22.50 | 22.60 | 22.65 | 22.70
1a) Average volume of A = 22.60 + 22.65 + 22.70/3
= 22.65cm^3
1bi) GIVEN: CB = 0.10moldm^-3
VB = 25cm^3
CA = ?
VA = 22.65cm^3
Equation of reaction:
H2C2O4(aq) + 2NaOH(aq) ====> Na2C2O4(aq) + 2H2O(l)
hence, nA = 1
Nb = 2
Using CAVA /CBVB = nA/nB
CA = CBVBnA/VanB
=0.10 × 25 × 1/22.65 × 2
CA = 0.055 moldm^-3
Concentration of A in moldm^-3 = 0.055
bii) Using:
gram concentration = molar concentration × molar mass
conc. Of A in gdm^-3 = 0.055 × [(1 × 2) + (12 × 2) + (16 × 4)]
= 0.055 × 90
= 4.95gdm^-3
======================
No2 solution
2a)
TEST
X + 5cm of distilled water, Divide the solution into 4 portion
OBSERVATION
Salt X is soluble in distilled water
INFERENCE
Salt X is soluble salt
=======================
2bi)
Test
-To the first portion, Add dilute NaOH in drop
-then in excess
OBSERVATION
-White precipitate solution is formed
-The white precipitate is soluble
INFERENCE
Zn^2+ Pb^2+ and AL^3+ are present
=====================
2bii)
TEST
-To the 2nd portion add dilute NH3 solution in drop
-then in excess
OBSERVATION
White gelatinous precipitate is formed which is insoluble in excesa
INFERENCE
Zn^2+,Pb^2+ and Al^3+ are present
======================
2biii)
TEST
To the 3rd portion, Add dilute HCL in drops
-then in excess
-heat the solution
OBSERVATION
White precipitate is formed which Dissolved on heating and re-appears on cooling
INFERENCE
Pb^2+ confirmed
======================
2ci)
TEST
Sample Y + concentrated HNO3
(Cii)
Heat the product formed in (ci)
OBSERVATION
Dirty white curd is formed
===========
It turn to yellow colouration on heating
INFERENCE
Protein is present
====================
2ciii)
TEST
Add concentrated NH3 to the product in (cii)
OBSERVATION
The product in (Cii) turns to orange colour
INFERENCE
Protein is present
=======================
No3
3ai)
i) SO2 change the colour of acidified K2Cr2O7 solution from Orange to green when it is passed through it by changing to Cr2(SO4)3
solution
ii) when zinc dust is added to CuSO4 solution, the solution turn from Blue to white
3aii)
i)Due to the formation of Cr2(SO4)3 solution
ii)Due to the formation of white ZnSO4 since zinc is higher in electrochemical series
3b)
=========================
Expospy.com posts all exam expo answer earlier than others
============================
GOODLUCK!!!
Verified NECO 2017 chemistry practical (Practical & Practical) question NECO Free 2017/2018 chemistry practical & Practical Questions and answers have been posted FOR FREE OOOO 2017/2018 NECO chemistry practical AND Practical ANSWERS NOW AVAILABLE. ANSWERS NOW POSTED BY ADMIN. CLICK BELOW IMAGE FOR THE ANSWERS NOW. NECO 2017/2018 verified chemistry practical Practical/ Questions and Answers Here (chemistry practical AND Practical) NECO chemistry practical expo,NECO 2017 chemistry practical answers, FREE chemistry practical ans for NECO, see NECO expo questions for free, correct chemistry practical ans,chemistry practical answers runz runs expo free real and correct NECO 2017 chemistry practical free expo runz runs ans answers online for freee see free answers online. NECO 2017 chemistry practical expo 2017/2018 NECO Free chemistry practical and Practical Answers have been posted chemistry practical 2017 NECO EXAMINATION EXPO/ANSWER RUNZ RUNS PracticalECTIVES and Practical. KINDLY COMMENT “ I NEED IT ” IN THE COMMENT BOX BELOW. REAL NECO Geography QUESTIONS & ANSWERS Direct To … RE: 2017/2018 NECO SSCE chemistry practical (Expo) NECO 2017/2018 certified chemistry practical questions and answers NECO MAY JUNE 2017 chemistry practical / Practical QUESTION AND EXPO I need NECO Ssce free expo site, how can I get the answer for, Congratulation to Those who Sub For Previous Subjects and Received KINDLY COMMENT “ I NEED IT ” IN THE COMMENT BOX BELOW. Their Answers 6 Hours before Exam chemistry practical. NECO chemistry practical expo, 2017 NECO chemistry practical, NECO chemistry practical ans, answers/questions chemistry practical NECO 2017 chemistry practical And Practical Answers – June/July Expo chemistry practical.
