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Chemistry
WAEC / WASSCE 2013
Atomic Structure and Periodic Table
Solution
The element with electron configuration 1s\(^2\) 2s\(^2\) 2p\(^6\) 3s\(^2\) 3p\(^1\) belongs to
A
s-block period 3, group 1
B
p-block, period 3, group 2
C
s-block, period 3, group 3
D
p-block, period 3, group 3
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
1s\(^2\) 2s\(^2\) 2p\(^6\) 3s\(^2\) 3p\(^1\) = 2, 8, 3.
The element is in period 3 and group 3.
Source: Myschool Past Questions Archive (Record #37661)
Chemistry
WAEC / WASSCE 2013
Matter & Separation Techniques
Solution
Which of the following instruments is used in detecting the presence of radiation?
A
Cathode ray tube
B
Geiger-Muller counter
C
Mass spectrometer
D
X-ray tube
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
The Geiger- Muller counter is a device for measuring radioactivity by detecting and counting ionizing particles.
Source: Myschool Past Questions Archive (Record #37643)
Chemistry
WAEC / WASSCE 2013
Stoichiometry & Mole Concept
Solution
The molecule which has a linear shape is
A
CH4
B
NH3
C
H2S
D
CO2
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The shapes of the molecules are:
CH\(_4\) - Tetrahedral; NH\(_3\) - Trigonal pyramidal; H\(_2\)S - Bent; C)\(_2\) - Linear.
Source: Myschool Past Questions Archive (Record #37648)
Chemistry
WAEC / WASSCE 2013
Atomic Structure and Periodic Table
Solution
In the periodic table all elements within the same group have the same
A
number of neutrons
B
number of valence electrons
C
number of isotopes
D
atomic number
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
The elements in the same group in the periodic table has the same number of electrons in the outer shell. That means, they have the same number of valence electrons.
Source: Myschool Past Questions Archive (Record #37662)
Chemistry
WAEC / WASSCE 2013
Matter & Separation Techniques
Solution
Which of the following halogens is liquid at room temperature?
A
lodine
B
Chlorine
C
Bromine
D
Fluorine
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Bromine is a reddish-brown liquid at room temperature.
Source: Myschool Past Questions Archive (Record #37663)
Chemistry
WAEC / WASSCE 2013
Atomic Structure and Periodic Table
Solution
Rare gases are stable because they
A
are chemically active
B
contain equal number of protons and neutrons
C
contain more electrons than protons
D
have octet structures
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
They are the most stable due to having the maximum number of valence electrons their outer shell can hold. That means rare gases have the octet configuration.
Source: Myschool Past Questions Archive (Record #37664)
Chemistry
WAEC / WASSCE 2013
Atomic Structure and Periodic Table
In the periodic table, alkaline earth metals can be found in group
A
l
B
ll
C
VI
D
VII
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option B.
Source: Myschool Past Questions Archive (Record #37665)
Chemistry
WAEC / WASSCE 2013
Matter & Separation Techniques
Solution
In which of the following series are the atoms arranged in order of increasing ionization energy?
A
Li, Na K
B
B, Be, Li
C
O, F, Ne
D
Be, mG, Ca
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
The ionization energy increases across the period. It increases up the group.
Source: Myschool Past Questions Archive (Record #37669)
Chemistry
WAEC / WASSCE 2013
Atomic Structure and Periodic Table
Solution
Which of the following bond types is responsible for the high boiling point of water?
A
Metallic bond
B
Covalent bond
C
lonic bond
D
Hydrogen bond
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The high boiling point is due to the breaking of the intermolecular force called Hydrogen bond.
Source: Myschool Past Questions Archive (Record #37670)
Chemistry
WAEC / WASSCE 2013
Atomic Structure and Periodic Table
In metallic solid, the forces of attraction is between the mobile valence electrons and the
A
atoms
B
neutrons
C
negative ions
D
positively charged nuclei
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option D.
Source: Myschool Past Questions Archive (Record #37671)
Chemistry
WAEC / WASSCE 2013
Atomic Structure and Periodic Table
Solution
The bonds in crystalline ammonium chloride are
A
covalent and dative
B
ionic and covalent
C
ionic, covalent and dative
D
ionic, covalent and hydrogen bond
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
N makes three covalent bonds with three Hydrogen and a coordinate (dative covalent) bond with with hydrogen ion, forming ammonium ion (NH\(_4 ^+\). The ammonium ion forms an ionic bond with chloride ion to form NH\(_4\)Cl.
Source: Myschool Past Questions Archive (Record #37672)
Chemistry
WAEC / WASSCE 2013
Matter & Separation Techniques
Solution
Which of the following elements is diatomic?
A
Sodium
B
Oxygen
C
Iron
D
Neon
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
The seven diatomic elements are Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, Iodine, Bromine.
Source: Myschool Past Questions Archive (Record #37673)
Chemistry
WAEC / WASSCE 2013
Stoichiometry & Mole Concept
Noble gas molecules are held together by
A
van der Waals forces
B
hydrogen bonds
C
dative bonds
D
covalent bonds
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #37674)
Chemistry
WAEC / WASSCE 2013
Matter & Separation Techniques
Solution
Which of the following statements about nuclear reaction is correct? The reaction
A
involves neutrons only
B
takes place inside the nucleus
C
is governed by temperature and pressure
D
involves protons and electrons only
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
A nuclear reaction is semantically considered to be the process in which two nuclei, or a nucleus and an external subatomic particle, collide to produce one or more new nuclides.
Source: Myschool Past Questions Archive (Record #37675)
Chemistry
WAEC / WASSCE 2013
Matter & Separation Techniques
Solution
Consider the reaction represented by the following equation: C\(_2\)H\(_2\) + yH\(_2\) → C\(_2\)H\(_6\). The value of y in the reaction is
A
4
B
3
C
2
D
1
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
C\(_2\)H\(_2\) + yH\(_2\) → C\(_2\)H\(_6\)
To balance the equation, we must have 2 carbon atoms on both sides and 6 hydrogen atoms.
On the LHS and RHS, carbon = 2 atoms.
On the LHS, Hydrogen = 2 + 2y.
On the RHS, Hydrogen = 6.
⇒ 2 + 2y = 6
2y = 4
y = 2.
Source: Myschool Past Questions Archive (Record #37676)