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Chemistry
UTME / JAMB 2018
Atomic Structure and Periodic Table
Solution
Which of the following statements is correct about the periodic table?
A
Elements in the same period have the same number of valence electrons
B
The valence electrons of the elements in the same period increase progressively across the period
C
Elements in the same group have the same number of electron shells
D
The non-metallic Properties of the elements tend to decrease across each period
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
The valence electrons refer to the number of electrons in the outer shell. Across a period (horizontal row), the valence electron increases.
Source: Myschool Past Questions Archive (Record #47319)
Chemistry
UTME / JAMB 2018
Atomic Structure and Periodic Table
Solution
The periodic classification is an arrangement of the elements
A
atomic weights
B
isotopic weights
C
molecular weights
D
atomic numbers
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Elements in the periodic table are arranged according to their atomic number (proton number). Electronegativity increase from left to right while atomic radius increases down the group
Elements in the periodic table are arranged according to their atomic number (proton number). Electronegativity increase from left to right while atomic radius increases down the group
Source: Myschool Past Questions Archive (Record #47320)
Chemistry
UTME / JAMB 2018
Acids, Bases, and Salts
Solution
If 1 litre of 2.2M sulphuric acid is poured into a bucket containing 10 litres of water and the resulting solution mixed thoroughly, the resulting sulphuric acid concentration will be
A
2.2M
B
1.1M
C
0.2M
D
0.11M
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Given:
C1 = 2.2 M , V1 = 1 Litre , C2 = ? V2 = 1 + 10 Litres ( because the volume of water has increased) = 11 Litres
Using the relationship C1V1 = C2V2
2.2 X 1 = C2 X 11
C2 = 2.2 /11
= 0.20 M - Option C
Source: Myschool Past Questions Archive (Record #47321)
Chemistry
UTME / JAMB 2018
Stoichiometry & Mole Concept
Diagram
Solution
In the shown experiment (Fig. 1) the litmus paper will initially
Attached Figure / Diagram
A
be bleached
B
turn green
C
turn red
D
turn blue
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
\(NH_4Cl → NH_3 + HCl\). rate of diffusion of substances depends too on their molar mass, the smaller the molar mass of a substance the faster the rate of diffusion of that substance. so the litmus paper initially turns blue because ammonia will get to it first since it diffuses faster than HCl.
Source: Myschool Past Questions Archive (Record #47322)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
The boiling of fat and aqueous caustic soda is referred to as
A
hydrolysis
B
esterification
C
acidification
D
saponification
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 #47323)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
Which of the following pairs of substances will react further with oxygen to form a higher oxide?
A
CO\(_2\) and H\(_2\)O
B
NO and H\(_2\)O
C
CO and CO\(_2\)
D
SO\(_2\) and NO
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 #47324)
Chemistry
UTME / JAMB 2018
Kinetics, Energetics and Equilibrium
In the preparation of oxygen by heating KCIO\(_3\) , in the presence of MnO\(_2\) only moderate heat is needed because the catalyst acts by \(_2\)
A
lowering the pressure of the reaction
B
increasing the surface area of the reaction
C
increasing the rate of the reaction
D
increasing the energy barrier of the reaction
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #47325)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
Solution
Methanoic acid mixes with water in all proportions and has about the same boiling point as water. Which of the following methods would you adopt to obtain pure water from a mixture of Sand, water and methanoic acid?
A
Extractive distillation
B
Filtration followed by distillation
C
Neutralization with sodium hydroxide followed by distillation
D
Neutralization with sodium hydroxide followed by filtration
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Due to the presence of maximum Azeotrope,we use extractive distilination (with extractive distilation agents like sulfone) used for mixtures with low relative volatility,nearing unity.
Azeotrope is a mixture of liquids that has a constant boiling point because the vapour has thesame composition as the mixture.
Source: Myschool Past Questions Archive (Record #47326)
Chemistry
UTME / JAMB 2018
Stoichiometry & Mole Concept
A quantity of electricity liberates 3.6g of Silver from its salt. What mass of aluminium Will be liberated from its salt by the same quantity of electricity? [Al = 27, Ag = 108].
A
2.7g
B
1.2g
C
0.9g
D
0.3g
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 #47327)
Chemistry
UTME / JAMB 2018
Acids, Bases, and Salts
An aqueous solution of a metal salt, M. gives a white precipitate with NaOH which dissolves in excess NaOH. With aqueous ammonia, the solution of M also gives a white precipitate which dissolves in excess ammonia Therefore the cation in M is
A
Zn
B
Ca
C
Al
D
Pb
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 #47333)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
What is the concentration of a solution containing 2g of NaOH in 100cm3 of solution? [Na = 23, O =16, H = 1]
A
0.40 moldm\(^{-3}\)
B
0.50 moldm\(^{-3}\)
C
0.05 moldm\(^{-3}\)
D
0.30 moldm\(^{-3}\)
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 #47335)
Chemistry
UTME / JAMB 2018
Stoichiometry & Mole Concept
Solution
How many atoms are present in 6.0g of magnesium? [Mg = 24, N.A = 6.02 x 10 \(^{23}\)mol]
A
1.20 x 10\(^{22}\)
B
2.4 x 10\(^{22}\)
C
1.51 x 10\(^{23}\)
D
3.02 x 10\(^{22}\)
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Using the formula, Number of moles = \(\frac{Number of atoms or molecules}{Avogadro number}\)
Given: Mass of Magnessium = 6g
Mass number of Mg = 24g/mol
Number of moles = \(\frac{mass}{Molar mass}\)
= \(\frac{6}{24}\) = \(\frac{1}{4}\) = 0.25 mole
Thus, Number of moles = \(\frac{Number of atoms or molecules}{Avogadro number}\)
n = \(\frac{N}{L}\)
0.25 = \(\frac{N}{(6.02\times 10\(^{23}}\)
N = \(0.25 \times 6.02\times 10\(^{23}\))
N = 1.505 X 10\(^{23}\)
N = 1.51 X 10\(^{23}\)
Source: Myschool Past Questions Archive (Record #47336)
Chemistry
UTME / JAMB 2018
Atomic Structure and Periodic Table
The radio isotope used in industrial radiography for the rapid checking of faults in welds and casting is?
A
carbon-14
B
phosphorus-32
C
cobalt-60
D
iodine-131
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option C.
Source: Myschool Past Questions Archive (Record #47337)
Chemistry
UTME / JAMB 2018
Atomic Structure and Periodic Table
Solution
Beryllium and Aluminium have similar properties because they
A
are both metals
B
belong to the same group
C
belong to the same period
D
are positioned diagonally to each other
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Beryllium and Aluminium exhibit similar properties because of their diagonal relationship on the periodic table, meaning they are positioned diagonally to each other, resulting in comparable atomic sizes, electronegativity, and a tendency to form covalent compounds, despite being in different periods and groups.
Source: Myschool Past Questions Archive (Record #47338)
Chemistry
UTME / JAMB 2018
Matter & Separation Techniques
Suitable reagents for the laboratory preparation of nitrogen are
A
sodium dioxonitrate(III) and ammonium chloride
B
sodium trioxonitrate(V) and ammonium chloride
C
sodium chloride and ammonium trioxonitrate(V)
D
sodium chloride and ammonium di-ozonitrate(III)
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 #47328)