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In our today’s post, we have provided the 2024/2025 NECO Chemistry practical questions and answers expo.
2024 NECO Chemistry Practical Correct Expo Questions And Answers
The National Examination Council (NECO) has organized the 2024 NECO Chemistry exam, which will begin on Thursday 4th July 2024.
QUESTIONS👇👇👇
2024 NECO Chemistry Solutions👇
*CHEMISTRY PRACTICAL ANSWERS*
(1)
Tabulate;
Burette readings;
|Rough |1st |2nd|3rd|
Final readings in cm³;
|22.00|20.10 |20.20|20.30|
Initial reading in cm³;
|0.00|0.00|0.00 |0.00|
Volume of A (acid) used cm³;
|22.00|20.10|20.20| 20.30|
The average titre
= 20.10+20.20+20.30/3
=60.60/3
= 20.20cm³
;Va 20.20cm³
(1bi)
Concentration of A in mol/dm³, Ca = ?
Concentration of A (g/dm³) = 4.40g/dm³.
.m.m of A, H²SO⁴ =(1*2)+(32*1)+(16*4)
=2+32+64
=98g/mol
Using concentration (mol/dm³) = Concentration (g/dm³)/m.m
Concentration (mol/dm³)
=4.40/98
=0.045mol/dm³
;: Concentration of A(mol/dm³) = 0.045mol/dm³
(1bii)
Concentration of B(mol/dm³) =???
Ca=0.045, Va=20.20, Vb=25.00, na=1, nb=1, cb=?
Using; CaVa/CbVb = na/nb
Cb=CaVanb/Vbna =0.045*20.20*1/25.00*1
Cb=0.036mol/dm³
(1biii)
Conc. of B(g/dm³) that reacted =??
molar mass of B, Na₂CO₃ = (23*2)+(12*1)+(16*3) = 106g/mol
Conc. of B(mol/dm³) = 0.036mol/dm3
Conc. (mol/dm³) = Conc. (g/dm³)/molar mass
(0.036/1) = Conc. (g/dm³)/106
Conc. (g/dm³) = 0.036*106 = 3.82g/dm³
Conc. of B(g/dm³) = 3.82/dm³
(1biv)
mass of the impurity in 1.0dm³ of B=??
Conc. of impurity (g/dm³) = 7.50 - 3.82 = 3.68g/dm³
:. Mass of impurity= Conc. (g/dm³) x vol. (dm³)
= 3.68x1 = 3.68g
(1bv)
Vol. of CO₂ produced in 1.0dm³ of B = ??
Mole of B= Conc. x Vol. (dm³)
Mole of B = 0.036*1
Mole of B =0.036mol
By proportion,
1mol of Na₂.10₃ = 1mol of CO₂
0.036mol of Na₂.10₃ = xmol of CO₂
mole of CO₂ produced = 1*0.036 = 0.036mol
:. Volume = mole * 22.4 = 0.81dm³
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(2)
[FILL THE TABLE WITH THE INFORMATION BELOW]
(2ai)
-TEST: C+5 cm³ of distilled water and shake thoroughly. Divide the solution into two portions
-OBSERVATION: It dissolves completely to give a colourless solution
-INFERENCE: C is a soluble salt
(2aii)
-TEST: To the first portion, add NaOH solution in drops.
-OBSERVATION: A white gelatinous precipitate is formed
-INFERENCE: Al³⁺ and Zn²⁺ present
(2aiii)
-TEST: Then add NaOH in excess
-OBSERVATION: The precipitate dissolve to give a colourless solution
-INFERENCE: Zn²⁺ present
(2aiv)
-TEST: To the second portion, add NH₃ solution in drops
-OBSERVATION: A white precipitate is formed
-INFERENCE: Al³⁺ and Zn²⁺ present
(2av)
-TEST: then in excess
-OBSERVATION: The white precipitate dissolves in excess NH₃
-INFERENCE: Zn²⁺ is confirmed
(2bi)
-TEST: 2cm³ of solution D + soda lime, heat, test with litmus paper.
-OBSERVATION: Ammonia gas (NH₃) is evolved, turning red litmus paper blue.
-INFERENCE: Presence of NH₄⁺ ions.
(2bii)
-TEST: Solution D + NaOH solution + CuSO₄ solution
-OBSERVATION: A blue precipitate formed
-INFERENCE: Presence of peptide bonds (proteins or peptides).
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(3ai)
I- to avoid the drop of the acid into the burette which will alter the reading
II- to avoid change in concentration and contamination
III- to avoid bubbles in the pipette
(3aii)
This can be done through crystallization. The solution is dissolved, heated to a high temperature and then allowed to cool. During cooling,the sodium chloride crystallized out.
(3bi)
(i)evaporating dish
(ii)Bunsen burner
(3bii)
Solubility
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KEEP REFRESHING THE PAGE AFTER 5 MINS MORE COMING ......
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Instructions To Of 2024 NECO Chemistry👇
2024 NECO Chemistry Practical Correct Expo Questions and Answers
In this article, you will read the steps and requirements for obtaining the 2024 NECO Chemistry Questions and Answers four hours (4 hours) before the exam.
The NECO Chemistry 2024 Paper is categorized into 3 parts:
- NECO Chemistry Essay 2024
- NECO Chemistry Objectives 2024
- NECO Chemistry Practical 2024
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