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Chemistry
WAEC / WASSCE 1991
Chemical Energetics & Thermochemistry
Solution
Which of the processes represented by the following equations has the greatest positive entropy change?
A
C6H3(l) → C6H 6 (g)
B
H2O (s) → H2O(l)
C
CuO(s) + H2(g) → Cu(s) + H2
D
Na2CO3(s) + nH2O(l) →Na 2CO3nH2O(s)
E
S(s) → S(l)
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
we have the greatest entropy when a substance changes from the liquid phase to the gaseous phase this is because the particles of gases are very loosely packed so they have the freedom to move around.
Source: Myschool Past Questions Archive (Record #36126)
Chemistry
WAEC / WASSCE 1991
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following elements can from more than one acidic oxide?
A
Hydrogen
B
Sulphur
C
Carbon
D
Alumium
E
Iron
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 #36127)
Chemistry
WAEC / WASSCE 1991
Stoichiometry, Mole Concept & Volumetric Analysis
CH2 = CH2 + H2SO4 → CH3 - CH2 -OSO3H. The reaction illustrated by the equation above is an example of
A
substitution
B
oxidation
C
reduction
D
addition
E
displacement
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 #36128)
Chemistry
WAEC / WASSCE 1991
Metals, Transition Elements & Extraction
Brass is an alloy of copper and
A
iron
B
chromium
C
zinc
D
tin
E
magnesium
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 #36129)
Chemistry
WAEC / WASSCE 1991
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Which of the following formula is that of a dicarboxylic acid?
A
(CH3CH 2)2CHCOOH
B
CH2(OH)2
C
CH3CH(OH)COOH
D
CH2(COOH)2
E
CH3COCOOH
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 #36130)
Chemistry
WAEC / WASSCE 1991
Electrolysis & Electrochemical Cells
The products of the electrolysis of dilute sodium chlorid solution with platinum electrodes are
A
hydrogen and oxygen
B
oxygen and chlorine
C
chlorine and water
D
sodium amalgam and chlorine
E
sodium hydroxide and 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 #36131)
Chemistry
WAEC / WASSCE 1991
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
Which of the following modes of motion is exhibited by the particles of a solid?
A
Vibrational and random motion
B
Vibrational and translational motion
C
Translational and random motion
D
Vibrational motion only
E
Translational motion only
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The cohesive forces binding the particles of a solid are strong enough to restrict their movement so that they are held together in a fixed point. They only vibrate and rotate about their fixed point.
Source: Myschool Past Questions Archive (Record #36132)
Chemistry
WAEC / WASSCE 1991
Periodic Table & Periodicity
Which of the following statements is not correct? Group 7 elements
A
are diatomic
B
are good oxidizing agents
C
are highly electronegative
D
have relatively low ionization potentials
E
have high electron affinity
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 #36133)
Chemistry
WAEC / WASSCE 1991
Non-Metals & Their Compounds
In which of the following are the substances arranged in their correct order of increasing melting point?
A
Sodium chloride, sulphur, diamond
B
Diamond, sodium chloride, sulphur
C
Sulphur, sodium chloride, diamond
D
Diamond, sulphur, sodium chloride
E
Sulphur, diamond, sodium chloride
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 #36134)
Chemistry
WAEC / WASSCE 1991
Stoichiometry, Mole Concept & Volumetric Analysis
A compound which liberates carbon (IV) oxide from a hydrogentrioxocarbonate (lV) could have the molecular formula
A
C2H5OH
B
C 3H 4
C
HCOOH
D
H2O2
E
C6H6
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 #36135)
Chemistry
WAEC / WASSCE 1991
Chemical Energetics & Thermochemistry
CH4(g) + 2O2(g) → 2H2O(l) + CO2(g) ∆H = 890KJ mo-1 ∆H in the reaction represented by the equation above is the enthalpy of
A
formation
B
combustion
C
solution
D
activation
E
neutralization
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 #36136)
Chemistry
WAEC / WASSCE 1991
Reaction Rates & Chemical Equilibrium
Solution
Consider the reaction represented by the equation below: H2(g) + 12(s) ⇌ 2HI(g) ∆H negative. Which of the following takes place when the temperature of the reaction vessel is decreased?
A
the gases condense
B
the yield of hydrogen increases
C
the concentration of the reactants remain constant
D
more of the hydrogen iodide decomposes
E
the yield of hydrogen iodide increases
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
Decreasing the temperature in an exothermic reaction (where heat is released) shifts the equilibrium to favor the formation of products. In this case, it increases the yield of hydrogen iodide (HI) as the system seeks to produce more heat to counteract the temperature drop.
Source: Myschool Past Questions Archive (Record #36137)
Chemistry
WAEC / WASSCE 1991
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Esterification of propane 1,2,3-triol and unsaturated higher carboxylic acids will produce
A
fats
B
soap
C
methly-propanoate
D
alkanols
E
oils
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 #36139)
Chemistry
WAEC / WASSCE 1991
Particulate Nature of Matter, Laws & Formulae
The ratio of reactants to products is 1: 3: 2 in the reaction represented by the equation below: N2,/SUB> (g) → 2NH3(g) which of the following law is demonstrated by this?
A
Boyle's law
B
Law of multiple proportion
C
Gay Lussac's law
D
Law of constant composition
E
Avogadro's law
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 #36140)
Chemistry
WAEC / WASSCE 1991
Oxidation, Reduction & Redox Reactions
In the redox reaction represented by the following equation: Cu2+aq + Zn(s) → Cu(s) + Zn2+
A
the oxidation number of copper increases
B
copper (ll) ions are reduced to copper atoms
C
zinc atoms are reduced to zinc ions
D
copper (ll) ions donate electrons to zinc atoms
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 #36141)