waec Chemistry Questions and answers 2023

Here is the waec chemistry question and Answers for 2023.

ANSWERS

(1a)
A transition element, also known as a transition metal, is an element that belongs to the d-block of the periodic table.

(1b) loading.

(1c)
The increase in the first ionization energies across a period is mainly due to the increasing effective nuclear charge and decreasing atomic radius. The stronger pull from the increasing nuclear charge and the closer proximity of the electrons to the nucleus make it harder to remove an electron, leading to higher ionization energies.
(1a)
A transition element, also known as a transition metal, is an element that belongs to the d-block of the periodic table.

(1bi) A, B
(1bii) C

(1c)
The increase in the first ionization energies across a period is mainly due to the increasing effective nuclear charge and decreasing atomic radius. The stronger pull from the increasing nuclear charge and the closer proximity of the electrons to the nucleus make it harder to remove an electron, leading to higher ionization energies.
(1a)
A transition element, also known as a transition metal, is an element that belongs to the d-block of the periodic table.

(1b)
(i) Element B (2:8:2)
(ii) Element C (2:8:1)

(1c)
The increase in the first ionization energies across a period is mainly due to the increasing effective nuclear charge and decreasing atomic radius. The stronger pull from the increasing nuclear charge and the closer proximity of the electrons to the nucleus make it harder to remove an electron, leading to higher ionization energies.
_*Number 5*_

*ai)*…

*Reaction between Iron (Fe) and Dilute H2SO4:*

Iron reacts with dilute sulfuric acid to form iron sulfate (FeSO4) and hydrogen gas (H2). The balanced chemical equation for this reaction is:

3Fe(s) + 4H2SO4(aq) -> 3FeSO4(aq) + 2H2(g) + 2H2O(l)

In this reaction, iron displaces hydrogen from the acid, resulting in the production of iron sulfate and hydrogen gas. The iron sulfate is soluble in water and remains in solution, while the hydrogen gas is released as a gas.

*Reaction between Aluminum (Al) and Dilute H2SO4:*

Aluminum reacts differently with dilute sulfuric acid due to the protective oxide layer that forms on its surface. The oxide layer prevents further reaction by acting as a barrier between the aluminum metal and the acid. However, the reaction can occur if the protective layer is disrupted or removed

2Al(s) + 3H2SO4(aq) -> Al2(SO4)3(aq) + 3H2(g)

In this reaction, aluminum sulfate (Al2(SO4)3) and hydrogen gas are produced. The aluminum sulfate formed is soluble in water and remains in solution, while the hydrogen gas is liberated as a gas.
Number 1di)

Two examples of aliphatic compounds are:

A. Ethane (C2H6): Ethane is a saturated hydrocarbon belonging to the alkane family. It consists of a straight chain of two carbon atoms bonded to each other, with six hydrogen atoms attached to the carbons.

B. Butanol (C4H10O): Butanol is an alcohol with a four-carbon straight chain. It has the chemical formula C4H10O and exists in four isomeric forms: n-butanol (normal butanol), sec-butanol (secondary butanol), isobutanol (isopropyl alcohol), and tert-butanol (tert-butyl alcohol).

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