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Chemistry
WAEC / WASSCE 1998
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following is not a property of trioxonitrate (V) salts?
A
Positive reaction to the brown ring test
B
Ability to dissolve in cold water
C
Decomposition on being strongly heated
D
Production of effervescence with saturated Na2CO3 solution
E
Evolution of gas with concentrated H2SO4 and copper turnings
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 #36612)
Chemistry
WAEC / WASSCE 1998
Acids, Bases, pH & Salts
Which of the following methods is suitable for the preparation of an insoluble salt?
A
Action of an acid on a metal
B
Double decomposition
C
Neutralisation
D
Action of an acid on a trioxocarbonate (IV)
E
Action of an acid on an oxide
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 #36613)
Chemistry
WAEC / WASSCE 1998
Stoichiometry, Mole Concept & Volumetric Analysis
What is the function of sulphur (IV) oxide in the reaction represented by the following equation? SO 2(aq) + 2H2S(g) → 3S (s) + 2H 2O (l)
A
Dehydrating agent
B
Oxidising agent
C
Bleaching agent
D
Acid
E
Precipitant
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 #36614)
Chemistry
WAEC / WASSCE 1998
Electrolysis & Electrochemical Cells
Which of the following will produce oxygen and hydrogen during its electrolysis using platinum electrode?
A
Glucose solution
B
Aqueous copper (ll) tetraoxosulphate (IV)
C
Dilute sodium chloride solution
D
Concentrated hydrochloric acid
E
Dilute copper (ll) chloride solution
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 #36615)
Chemistry
WAEC / WASSCE 1998
Electrolysis & Electrochemical Cells
Solution
What mass of copper would be deposited by a current of 1. 0 ampere passing for 965 seconds through copper (ll) tetraoxosulphate (IV) solution? [Cu = 63.5; 1F = 96500C]
A
0.318g
B
0.635g
C
18g
D
6.35g
E
9.65g
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Cu2+ + 2e- → Cu, From the equation 2 Faraday will liberate 63.5gm of copper The quantity of electricity passed (Q) Q = 1. 0 965 = 965 coulomb :. 2 x 96500 → 63.5, 965 → x. x = 965 / 2x96500 x 63.5 = 0.3175g \(\approx\) 0.328
Source: Myschool Past Questions Archive (Record #36616)
Chemistry
WAEC / WASSCE 1998
Water, Solutions & Solubility
Substances which absorb water from the atmosphere without dissolving in it are sid to be
A
anhydrous
B
hygroscopic
C
insolube
D
hydrated
E
efflorescent
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 #36618)
Chemistry
WAEC / WASSCE 1998
Stoichiometry, Mole Concept & Volumetric Analysis
Pipe-borne water is usually chlorinated in order to
A
improve the teste of the water
B
remove the hardness in the water clear
C
coagulate sediments in the water
D
kill harmful bacteria in the water
E
make the water clear and colourless
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 #36622)
Chemistry
WAEC / WASSCE 1998
Reaction Rates & Chemical Equilibrium
Solution
Which of the following can be added to dissolve the precipitate formed in the reaction represented by the following equation? CaCl2(aq) + H2C2O 4(s) ⇌ CaC 2O2
A
Calcium chloride solution
B
Concentrated hydrochloric acid
C
Ethanol
D
Ethanedioc acid
E
Aqueous ammonia
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Option B is the correct answer. The white precipitate formed in the given equilibrium reaction is calcium oxalate (CaC\(_2\)O\(_4\)). Calcium oxalate is the salt of a weak acid (ethanedioic acid, (H\(_2\)C\(_2\)O\(_4\)). When a strong acid like concentrated hydrochloric acid is added, it provides a high concentration of hydrogen ions (H\(^+\)). These (H\(^+\) ions react with the oxalate ions (C\(_2\)O\(_4^{2-}\)) to form poorly dissociated weak ethanedioic acid molecules. This removes free oxalate ions from the right side of the equilibrium, shifting the system back to the left according to Le Chatelier's principle, thereby dissolving the solid precipitate.
Source: Myschool Past Questions Archive (Record #36624)
Chemistry
WAEC / WASSCE 1998
Chemical Energetics & Thermochemistry
The spontaneity of a chemical reaction is determined by the change in the
A
concentration of the reactants
B
temperature of the system
C
free energy of the system
D
pressure applied to the system
E
volume of the reactants
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 #36625)
Chemistry
WAEC / WASSCE 1998
Water, Solutions & Solubility
Two metallic ions commonly present in hard water are
A
Ca2+ and Zn2+
B
Cu2+ and Na+
C
Mg2+ and Ca2+
D
Fe2+ and Na+
E
Zn2+ and Cu2+
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 #36626)
Chemistry
WAEC / WASSCE 1998
Metals, Transition Elements & Extraction
Rusting of iron is an example of
A
deliquescence
B
decomposition
C
displacement reaction
D
redox reaction
E
reversible reaction
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 #36627)
Chemistry
WAEC / WASSCE 1998
Metals, Transition Elements & Extraction
Aluminium is extracted from
A
magnetite
B
cryolite
C
bauxite
D
cassiterite
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 #36630)
Chemistry
WAEC / WASSCE 1998
Stoichiometry, Mole Concept & Volumetric Analysis
Metals are said to be malleable because they
A
are good conductors heat
B
are good conductors of electricity
C
can be beaten into sheets
D
can be alloyed
E
can be polished
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 #36634)
Chemistry
WAEC / WASSCE 1998
Stoichiometry, Mole Concept & Volumetric Analysis
A device used in the laboratory for intermittent production of gases without heating is
A
Leibing condenser
B
aspirator
C
delivery tube
D
inverted funnel
E
Kipp's apparatus
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option E.
Source: Myschool Past Questions Archive (Record #36635)
Chemistry
WAEC / WASSCE 1998
Organic Chemistry I: Hydrocarbons & Crude Oil
Which of the following can undergo both addition reactions and substitution reactions?
A
Benzene
B
Pentane
C
Propene
D
Hexane
E
Ethene
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 #36636)