WAEC GCE(FIRST SERIES)2022 CHEMISTRY ESSAY,OBJ AND PRACTICAL-ANSWERS

WAEC GCE(FIRST SERIES)2022 CHEMISTRY ESSAY, OBJ AND PRACTICAL-ANSWERS.EXAMKING.NET
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CHEMISTRY PRACTICAL-ANSWWERS-EXAMKING.NET
(3a) Na2Co3 and CaCO3(3a)
(i) Sodium trioxocarbonate(iv)
(ii) Calcium trioxocarbonate (iv)

(3aii)
(i)Na²CO³ + 2HCl ——–> 2NaCl + H²O + CO².
(ii)CaCO³(s) + HCl——>CaCl²(aq)+H²O(i)+CO²(g)

(3bi)
(i)K²CO³
(ii)Na²CO³.

(3bii)
(i)Ammonium chloride
(ii)Sodium hydrogen tetraoxosulphate (vi)

(3biii)
Dissolution of acid anhydride

(3c)
(i) Distillation process
(ii) Crystallization
(iii) Boiling
(iv) Filtration

(3d)
This is because it is quickly oxidized
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(1ai)
Burette reading; |1|2|3|

Final reading; |14.45| |38.65|

Initial reading; |1.80• 14.45| |

Titre value; | |12.15|12.05|



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CHEMISTRY-OBJ-EXAMKING.NET
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CHEMISTRY-ANSWWERS-EXAMKING.NET
Complete No1 Posted
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(3a)
(3bi)
Activation energy is defined as the minimum amount of extra energy required by a reacting molecule to get converted into product.

(3bii)
An ineffective collision is one that does not result in product formation. The colliding molecules, or other particles, do not have appropriate orientation to one another in the collision to lead to a reaction.

(3ci)
The hydrides of the first elements in groups 15 – 17, namely NH3, H2O and HF respectively, show abnormally high values for melting and boiling points. This is due to the ability to form extensive inter-molecular H-bonding.

(3cii)
(i) Stronger hydrogen bonds
(ii) Molecular associations

(3di)

(3dii)
Lead oxide, Nitrogen dioxide and Oxygen.

(3diii)
(i) Yellow
(ii) White
(iii) White

(3iv)
Coke
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(1ai)
Electrolysis is the process by which ionic substances are decomposed (broken down) into simpler substances when an electric current is passed through them.

(1aii)The concentration of ion.

(1b)Rate of Chemical Reaction is the speed at which a chemical reaction proceeds. It is often expressed in terms of either the concentration (amount per unit volume) of a product that is formed in a unit of time or the concentration of a reactant that is consumed in a unit of time.
(1c)
The iodide ions are less electronegative than chloride ions and so they are better reducing agents than chloride ions.

(1di)
3Cl + 6NaOH – -> NaClO₃ + 5NaCl + 3H₂O

(1dii)
Oxidation reaction

(1ei)
CₙH₂ₙ₊₁ COOH = 74
12n +2n +1 +12 +16 +15 +1 =74
14n + 46 =74
14n = 28
n = 2
= CₙH₂ₙ₊₁COOH
= C₂H₄₊₁COOH
= C₂H₅COOH

H H OH
| | |
H – C – C – C =O
| |
H H

(1eii)
Propanoic Acid

(1fi)
This is because of its polarity and ability to form hydrogen bonds therefore it dissolves different molecules.

(1fii)
Sulphur dioxide being a strong reducing agent, reduces the purple coloured solution to form a colourless solution.

(1gi)

(1gii)
Methane

(1giii)
Double decomposition

(1hi)
Solution of silver trioxonitrate(v)

(1hii)
Oxidation reaction

(1i)
The first Ionization of Nitrogen is higher than that of Oxygen because of the inner screening effect in the nucleus of Nitrogen conferring higher Ionization energy.

(1j)
3- Methylpropane




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CHEMISTRY PRACTICAL-ANSWWERS-EXAMKING.NET
(1ai)
Burette reading; |1|2|3|

Final reading; |14.45| |38.65|

Initial reading; |1.80• 14.45| |