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Chemistry
UTME / JAMB 2019
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
How many alkoxyalkanes can be obtained from the molecular formula C\(_4\)H\(_{10}\)O?
A
4
B
2
C
1
D
3
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
ethoxlethane
methoxylpropane
propoxylmethane
Source: Myschool Past Questions Archive (Record #56017)
Chemistry
UTME / JAMB 2019
Oxidation, Reduction & Redox Reactions
The reaction \(2H_2 S + SO_2 \to 3S + 2H_2 O\) is
A
not a redox reaction because there is no oxidant in the reaction
B
not a redox reaction because there is no reductant in the reaction
C
a redox reaction in which H\(_2\)S is the oxidant and SO\(_2\) is the reductant
D
a redox reaction in which SO\(_2\) is the oxidant and H\(_2\)S is the reductant
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 #56018)
Chemistry
UTME / JAMB 2019
Stoichiometry, Mole Concept & Volumetric Analysis
A solution X, on mixing with AgNO\(_3\) solution gives a white precipitate soluble in aqueous NH\(_3\), a solution Y, when also added to X, also gives a white precipitate which is soluble when heated solutions X and Y respectively contain
A
Al\(^{3+}\), Cl\(^-\)
B
Hg\(^+\), SO\(_4 ^{2-}\)
C
Pb\(^{2+}\), Cl\(^-\)
D
Ag\(^+\), SO\(_4 ^{2-}\)
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 #56019)
Chemistry
UTME / JAMB 2019
Atomic Structure, Orbitals & Nuclear Chemistry
Solution
How many electrons will be found in the nucleus of an atom with mass number 23 and 17 neutrons?
A
none
B
6
C
7
D
8
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Electrons are found in the orbit of the atom. They revolve around the nucleus. There's no electron found in the nucleus of an atom.
Source: Myschool Past Questions Archive (Record #56020)
Chemistry
UTME / JAMB 2019
Particulate Nature of Matter, Laws & Formulae
Solution
An element Z contains 80% of \(^{16} _8\)Z and 20% of \(^{18} _8\)Z. Its relative atomic mass is
A
16.2
B
17.6
C
16.0
D
16.4
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
R.A.M of Z = \(16(\frac{80}{100}) + 18(\frac{20}{100})\)
= \(12.8 + 3.6\)
= 16.4
Source: Myschool Past Questions Archive (Record #56021)
Chemistry
UTME / JAMB 2019
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
When the end alkyl groups of ethyl ethanoate are interchanged, the compound formed is
A
propylmethanoate
B
ethylpropanoate
C
methyl ethanoate
D
methyl propanoate
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The structural formula for ethyl ethanoate is
After interchanging, we have
Which is the structural formula for methyl propanoate.
Source: Myschool Past Questions Archive (Record #56022)
Chemistry
UTME / JAMB 2019
Chemical Energetics & Thermochemistry
Solution
The part of the total energy of a system that accounts for the useful work done in a system is known as
A
Enthalpy change
B
None of the above
C
Gibb's free energy
D
Entropy
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Gibb's free energy is the fraction of the total energy of a system that accounts for how much useful work can be done in a system.
Source: Myschool Past Questions Archive (Record #56023)
Chemistry
UTME / JAMB 2019
Reaction Rates & Chemical Equilibrium
Solution
Which of the following factors will speed up the rate of evolution of carbon (iv) oxide in the reaction below?
2HCl + CaCO\(_3\) → CaCl\(_2\) + H\(_2\)O + CO\(_2\)
A
Increasing the concentration of the acid
B
Increasing the surface area of CaCO\(_3\)
C
A and B
D
Reducing the concentration of the acid
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
The following factors increase a reaction rate
- Increase in concentration of reactants
- Increase in temperature
- Addition of catalyst
- Increase in the surface area of reactant(s)
Source: Myschool Past Questions Archive (Record #56024)
Chemistry
WAEC / WASSCE 2019
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
Which of the following metals reacts slowly with cold water?
A
Iron
B
Silver
C
Calcium
D
Pottassium
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Calcium reacts very slowly with cold water
Source: Myschool Past Questions Archive (Record #57916)
Chemistry
WAEC / WASSCE 2019
Non-Metals & Their Compounds
Solution
The bleaching action of chlorine is through the process?
A
Hydration
B
Hydrolysis
C
Reduction
D
Oxidation
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The bleaching action lof chlorinr is due to its ability to react with water to form oxochlorate(i)acid
Source: Myschool Past Questions Archive (Record #57929)
Chemistry
WAEC / WASSCE 2019
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
If 6.5g of magnesium ribbon reacts completely with Hydrochloric acid, how many grams of hydrogen gas would be liberated?
Mg(s) + 2 HCl(aq) --> MgCl 2(aq) + H 2(g)
[ H = 1.0, Mg = 24.0 ]
A
0.54g
B
0.70g
C
1.08g
D
1.40g
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
24g of Mg will liberate 2g of H
: 6.5g of Mg will liberate Xg of H
= ( 6.5 X 2 ) / 24
= 0.5416g of Hygrogen ( H )
Source: Myschool Past Questions Archive (Record #57983)
Chemistry
WAEC / WASSCE 2019
Periodic Table & Periodicity
Calcium and magnesium belong to the group of the periodic table because both?
A
are metals
B
form cations
C
form colourless salts
D
have same number of valence electrons
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 #57984)
Chemistry
WAEC / WASSCE 2019
Atomic Structure, Orbitals & Nuclear Chemistry
Solution
The periodic table is an arrangement of elements according to their?
A
Oxidation number
B
Atomic number
C
Mass number
D
Number of neutrons
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Elements are arranged in order of increasing atomic number
Source: Myschool Past Questions Archive (Record #57835)
Chemistry
WAEC / WASSCE 2019
Chemical Bonding & Intermolecular Forces
Solution
A solid with higher melting and boiling points is likely to be?
A
Covalent compound
B
A Dative compound
C
An Electrovalent compound
D
A Non-metal
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Ionic Compounds / Electrovalent compounds Have A High Melting Point and High Boiling Point.
Source: Myschool Past Questions Archive (Record #57872)
Chemistry
WAEC / WASSCE 2019
Periodic Table & Periodicity
Solution
Which of the substances is non-polar?
A
Bromine
B
Ammonia
C
Water
D
Hydrogen Bromide
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Br2 (Bromine) is nonpolar because, in this molecule, both bromine atoms have the same electronegativity due to which both atoms have equal charge distribution and results in a net-zero dipole moment.
Source: Myschool Past Questions Archive (Record #57990)