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English Language
WAEC / WASSCE 2002
Lexis, Structure & Register (Cloze & Vocabulary)
In question numbered 100 above, choose the best option from letters A - D that best completes the gap.
A
sound
B
droning
C
cacophony
D
disturbance
medium Difficulty
Verified Correct Answer: Option A
Grammar & Contextual Explanation
No expanded working has been attached for this question yet. The verified answer is Option A.
Source: Myschool Past Questions Archive (Record #25122)
Chemistry
UTME / JAMB 2002
Nature of Matter & Separation Techniques
Diagram
Solution
In the diagram above, the curve that represents the production of oxgyen gas from the decomposition of KCIO3 in the presence of MnO2 catalyst is
Attached Figure / Diagram
A
R
B
P
C
S
D
Q
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
The decomposition of KClO\(_3\) in the presence of MnO\(_2\) catalyst changes solid to gas, which is a sublimation process, as Oxygen gas is produced.
MnO\(_2\)
2KClO\(_3\) → 2KCl + 3O\(_2\)
Decreasing the pressure on a solid causes it to turn into a gas through a process called sublimation. Thus, the effect of pressure on solid is negligible. Consequently, from the curve given in the question, it means pressure is constant as the decomposition reaction proceeds to completion.Therefore, the curve is represented by R.
Source: Myschool Past Questions Archive (Record #31608)
Chemistry
UTME / JAMB 2002
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Diagram
Solution
The compound above is
Attached Figure / Diagram
A
glycol
B
primary alkanol
C
secondary alkanol
D
tertiary alkanol
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
A secondary alcohol is an organic compound where a hydroxyl group (-OH) is attached to a carbon atom that is bonded to two other carbon atoms.
Source: Myschool Past Questions Archive (Record #31611)
Chemistry
WAEC / WASSCE 2002
Atomic Structure, Orbitals & Nuclear Chemistry
Solution
If the relative molecular mass of an element is not a whole number, it can be deduced that the element is
A
naturally radioactive
B
abundant in nature
C
a transition metal
D
an isotopic mixture
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Option D is correct because the relative atomic or molecular mass of an element is a weighted average of the masses of all its naturally occurring isotopes. Isotopes are atoms of the same element that have different numbers of neutrons, resulting in different mass numbers. Because these isotopes exist in varying percentages (abundances) in nature, their average mass is often a decimal rather than a whole number.
Source: Myschool Past Questions Archive (Record #36890)
Chemistry
WAEC / WASSCE 2002
Atomic Structure, Orbitals & Nuclear Chemistry
Solution
The atomic number of chlorine is 17. What is the number of electrons in a chloride ion?
A
16
B
17
C
18
D
19
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Cl = 17 = 2, 8, 7.
Cl ion = Cl\(^-\) = 2, 8, 8 = 18.
Source: Myschool Past Questions Archive (Record #36892)
Chemistry
WAEC / WASSCE 2002
Oxidation, Reduction & Redox Reactions
Consider the following equation; Cr2O7(aq)2- + 14H+(aq) + 6e- → 2Cr3+(aq) + 7H2O(I). The oxidation number of chromium changes from
A
-2 to + 3
B
- 2 to + 6
C
+ 6 to + 3
D
+ 7 to + 6
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 #36940)
Chemistry
WAEC / WASSCE 2002
Electrolysis & Electrochemical Cells
Which of the following ions require the largest quantity of electricity for discharge at an electrode?
A
2.0 mole of Q 3+
B
2.5 mole of R2+
C
3.0 mole of T-
D
4.0 mole of Y-
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 #36941)
Chemistry
WAEC / WASSCE 2002
Electrolysis & Electrochemical Cells
If two metallic ions of the same concentration migrate to a graphite cathode, the one that would be preferentially discharged is the one that has the
A
smaller mass
B
lower electrical charge
C
greater stability in solution
D
stronger tendency to accept 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 #36942)
Chemistry
WAEC / WASSCE 2002
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Solution
Which of the following processes takes place during the production of margarine from vegetable oils?
A
Esterification
B
Hydrolysis
C
Hydrogenation
D
Saponification
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Margarine is produced by converting liquid vegetable oils into solid or semi-solid fats through a chemical process called hydrogenation.
Vegetable oils are polyunsaturated, containing many carbon-carbon double bonds. During hydrogenation, hydrogen gas is added to these double bonds in the presence of a metal catalyst (usually nickel). This process "hardens" the oil by increasing its saturation, which raises its melting point and results in the spreadable, solid consistency characteristic of margarine.
Source: Myschool Past Questions Archive (Record #36947)
Chemistry
WAEC / WASSCE 2002
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Which of the following compounds can be represented by the molecular formula C2H6O?
A
Propanal
B
Ethanol
C
Methanoic acid
D
Glucose
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 #36948)
Chemistry
WAEC / WASSCE 2002
Organic Chemistry I: Hydrocarbons & Crude Oil
Solution
When alkynes are hydrogenated completely, they produce compounds with the general molecular formula
A
C nH n
B
C nH 2n+2
C
CnH 2n
D
CnH2n-2
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
when alkyne(\(C_nH_{2n - 2}\)) are hydrogenated completely, alkanes( \(C_nH_{2n + 2}\)) are produced.
Source: Myschool Past Questions Archive (Record #36949)
Chemistry
WAEC / WASSCE 2002
Organic Chemistry I: Hydrocarbons & Crude Oil
The following compounds are hydrocarbons except
A
methylpropanoate
B
2-methylbutane
C
benzene
D
cyclohexane
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 #36952)
Chemistry
WAEC / WASSCE 2002
Water, Solutions & Solubility
Which of the following statements about soapless detergents is correct? They
A
lather readily with hard water
B
increase the surface tension of water
C
cause hydrolysis of salts in water
D
from a curdy precipitate with soft water
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 #36954)
Chemistry
WAEC / WASSCE 2002
Stoichiometry, Mole Concept & Volumetric Analysis
The atom of an element X is represented as \(^y_z X\). The basic chemical properties of X depend on the value of
A
Y
B
Z
C
Y - Z
D
Z - Y
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 #39946)
Chemistry
WAEC / WASSCE 2002
Atomic Structure, Orbitals & Nuclear Chemistry
A hydrogen atom which has lost an electron contains
A
one proton only
B
one neutron only
C
one proton and one neutron
D
one proton, one electronic and one neutron
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 #39948)