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Chemistry
WAEC / WASSCE 1988
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
Given that 32.0g sulphur contains 6.02 x 10 23 sulphur atoms how many atoms are there in 2.70g of aluminium? {Al = 27, S =32}
A
6.02 x 10 23
B
3.01 x 1022
C
6.02 x 1022
D
5. 08 x 1022
E
3.01 x 1022
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
27g Aluminium = \(6.02 \times 10^{23}\)
1g Al = \(\frac{6.02 \times 10^{23}}{27}\)
2.7g Al = \(\frac{6.02 \times 10^{23}}{27} \times 2.7\)
= \(6.02 \times 10^{22} Al \) atoms
Source: Myschool Past Questions Archive (Record #36027)
Chemistry
WAEC / WASSCE 1988
Stoichiometry, Mole Concept & Volumetric Analysis
The empirical formula of hydrocarbon containing 0. 12 mole of carbon and 0.36 mole of hydrogen is
A
CH2
B
CH3
C
C2H2
D
C2H4
E
C2H6
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 #36028)
Chemistry
WAEC / WASSCE 1988
Water, Solutions & Solubility
Solution
A salt which loses mass when exposed to air is
A
hygroscopic
B
deliquescent
C
efflorescent
D
fluorescent
E
effervescent
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
When a salt loses mass (water of crystallization) when exposed to air, it is said to be efflorescent.
Efflorescence refers to the spontaneous loss of water of crystallization by a hydrated salt when exposed to air. This occurs when the vapor pressure of the water within the salt's crystals is higher than the partial pressure of water vapor in the surrounding air. Consequently, the water molecules leave the salt crystals, causing the salt to lose mass and potentially become powdery.
Source: Myschool Past Questions Archive (Record #36029)
Chemistry
WAEC / WASSCE 1988
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Detergents are better than soaps for laundry because
A
detergents are synthetic while soaps are not
B
detergents are more soluble in water than soaps
C
scum is precipitated when soaps are used with hard water but not with stergents
D
soaps from soluble saits with ions causing hardness of water while detergents do not
E
soaps are in bars while detergents are in powder form
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 #36030)
Chemistry
WAEC / WASSCE 1988
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following is used as an anaesthetic?
A
CHI3
B
CHCI3
C
CH3OH
D
C2H5OH
E
CHBr3
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 #36031)
Chemistry
WAEC / WASSCE 1988
Chemical Bonding & Intermolecular Forces
Which of the following types of hybridization gives rise to tetrahedral molecules?
A
sp
B
sp2
C
sp3
D
sp3d
E
sp3d2
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 #36032)
Chemistry
WAEC / WASSCE 1988
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following is a neutral oxide?
A
Nitrogen (IV0 oxide
B
Carbon (IV) oxide
C
Sulphur (IV) oxide
D
Phodphoorus (IV) oxide
E
Nitrogen oxide
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 #36033)
Chemistry
WAEC / WASSCE 1988
Non-Metals & Their Compounds
Which of the following statements is not correct?
A
Carbon exhibits allotropy
B
Sulphur exhibits allotropy
C
Chlorine exhibits allotopy
D
Nitrogen is a gas
E
Argon is a noble gas
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 #36034)
Chemistry
WAEC / WASSCE 1988
Atomic Structure, Orbitals & Nuclear Chemistry
The following are uses of radioactive isotopes except for
A
sterilization of medical equipment
B
tracing reaction paths
C
dating elements
D
radiography
E
determining equilibrum positions
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 #36035)
Chemistry
WAEC / WASSCE 1988
Metals, Transition Elements & Extraction
The main characteristic feature of transition metals is that they
A
have the same atomic size
B
are reducing agents
C
from ions easily
D
have variable oxidation states
E
are highly electropositive
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 #36036)
Chemistry
WAEC / WASSCE 1988
Organic Chemistry I: Hydrocarbons & Crude Oil
The following are heavy chemicals except
A
tetraoxosulphate (IV) acid
B
caustic soda
C
sodium trioxocarbonate (IV)
D
ethene
E
dyes
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 #36037)
Chemistry
WAEC / WASSCE 1988
Stoichiometry, Mole Concept & Volumetric Analysis
What quantity of silver is deposited when 96500C of electricity is passed through a solution containing silver ions? (Ag = 108, 1F = 96500C)
A
1.08g
B
40g
C
10,.8g
D
21.6g
E
108g
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 #36038)
Chemistry
WAEC / WASSCE 1988
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
Bubbling of carbon (IV)oxide into calcium hydroxide solution results in the formation of
A
CaCO3
B
CuCO3
C
ZnCO3
D
Na2CO3
E
MgCO3
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
When carbon (IV) oxide (CO\(_2\)) is bubbled into a calcium hydroxide solution (Ca(OH)\(_2\)), also known as limewater, it reacts to form calcium carbonate (CaCO\(_3\)) and water (H\(_2\)O). Calcium carbonate is an insoluble white precipitate, which causes the clear limewater to turn "milky" or cloudy.
Source: Myschool Past Questions Archive (Record #36039)
Chemistry
WAEC / WASSCE 1988
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following is not decomposed by heat?
A
CaCO3
B
CuCO3
C
ZnCO,sub>3
D
Na2CO3
E
MgCO3
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 #36040)
Chemistry
WAEC / WASSCE 1988
Metals, Transition Elements & Extraction
Which of the following is not true of the rusting of iron?
A
Rusting is a reduction process
B
Rusting of iron takes place in the presence of oxygen and moisture
C
the rust formed is reddish brown
D
the major constituent of rust is hydrated iron (lll) oxide
E
rusting is similar to burning
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 #36041)