Gce All School News Education Guides Technology General

JOIN OUR WAEC & NECO WHATSAPP SAPP GROUP

Neco 2023 Chemistry Practical Questions And Answers
By on July 13th, 2023. Neco
0

CHEMISTRY-PRACTICAL-ANSWERS!

(1a)
[TABULATE]

Burette Reading (cm³) | Rough | Titration I | Titration II | Titration III |
Final Reading (cm³) | 21.50 | 43.00 | 22.00 | 21.50 |
Initial Reading (cm³) | 0.00 | 21.50 | 00.00 | 00.00 |
Volume of A used (cm³) | 21.50 | 21.50 | 22.00 | 21.50 |

(1ai)
Average Volume of acid used = 21.50 + 21.50/2 = 21.50cm³

(1aii)
Solution B[Sodium trioxocarbonate (iv)] feels soapy

(1bi)
Conc. B in mol/dm³ =?
Ca= 0.04, Va= 21.50cm³, na= 1
Cb= ? , Vb= 25.00cm³ nb= 1

CaVa/CbVb = na/nb = 0.04×21.50/Cb×25.00 = 1/1
Cb= 0.04×21.50/25.00 = 0.86/25.00
Cb= 0.0344mol/dm³

(1bii)
Conc. of B in g/dm³ = Conc. of B in mol/dm³ × molar mass of B

Molar mass of B(NaCO₃)= (23×2) + 12 + (16×3) = 106

:. Conc. of B in g/dm³ = 0.0344×106 = 3.6g/dm³


(1biii)
1 mole of Na₂Co₃ = 1mole of Na₂So₄

:. 0.0344 mole of Na₂Co₃ = 0.0344 mole of Na₂So₄
№ of mole= mass/ molar mass

Molar mass of Na₂So₄= (23×2)+32+(16×4)=142
:. 0.0344 = mass/142
Mass=142×0.0344=4.9g

(1biv)
1 mole of Na₂Co₃= 1 mole of CO₂

0.0344 mole of Na₂Co₃ = 0.0344 mole of CO₂
:. № of mole = volume/ molar volume = 0.0344 = volume of CO₂/22400cm³
=771cm³

(2ai)
[TABULATE]

=TEST=
C + heat

=OBSERVATION=
Formation of yellow flame

=INFERENCE=
Na⁺ present

(2aii)
=TEST=
C + distilled water + shake

=OBSERVATION=
It readily dissolve in water

=INFERENCE=
C is a soluble in water

(2aiii)
=TEST=
Solution C + litmus paper

=OBSERVATION=
It changes moist red litmus to blue and no effect blue

=INFERENCE=
Solution C is alkaline

(2bi)
=TEST=
1st portion of solution C + barium chloride

=OBSERVATION=
White precipitate formed

=INFERENCE=
CO₃²⁻ , SO₄²⁻ , S²⁻ or SO₃²⁻

(2bii)
=TEST=
Add dilute HCl to product in (bi)

=OBSERVATION=
White precipitate dissolved

=INFERENCE=
CO₃ , SO₃²⁻ or S₃²⁻

(2biii)
=TEST=
To the second portion add phenolphthalein

=OBSERVATION=
Purple colour observed

=INFERENCE=
C is alkaline


(3ai)
Sulphur (iv) oxide and hydrogen sulphide.

(3aii)
Liberation of hydrogen gas with pop sound and formation of green iron (ii) chloride solution

(3aiii)
Spatula, beaker, weighing balance, standard volumetric flask

(3bi)
Solution turns red

(3bii)
Turns from brown to green

(3biii)
A colourless, odourless, acidic gas liberated which turns blue litmus paper red and turn lime water milky.

Join Our Whatsapp Group

About Author
Jambclass

I’m a blogger living in Nigeria. I like to share education guides and information from various sources. I created Jambclass to serve as a platform to disseminate quality, credible and dependable information regarding various ways to excel academically. I strive to keep Nigerian youths and students informed. I started this Blog with the Vision To Inspire and Empower Young Persons; helping them Realize and Maximize their Potential.

RECOMMENDED TOPICS
No Comments Yet

Leave a Reply

NOTE:- Your comment will appear after it has been approved by an admin.