Question Library
Browse, filter, and study verified past examination questions with step-by-step mathematical reasoning.
Searching 18,000+ Questions...
Sifting topics, KaTeX formulas & verified solutions
Showing 25456–25470 of 29821 verified questions
Sort by:
Chemistry
WAEC / WASSCE 1990
Acids, Bases, pH & Salts
Which of the following salts in aqueous solution will have a pH greater than 7?
A
NaCl
B
ACI3
C
FeCI3
D
Na 2SO4
E
K 2CO3
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 #36102)
Chemistry
WAEC / WASSCE 1990
Electrolysis & Electrochemical Cells
The compound of copper which is used in electroplating dyeing, printing, wood preservation and as a fungicide is
A
copper (ll) hydroxide
B
copper (ll) trioxonitrate (V) pentahydrate
C
copper (ll) tetraoxosulphate (VI) pentahydrate
D
copper (ll) oxide
E
copper (ll) trioxocarbonate (lV)
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 #36103)
Chemistry
WAEC / WASSCE 1990
Stoichiometry, Mole Concept & Volumetric Analysis
What is the molecular formula of a compound whose empirical formula is CH2O and molar mass is 180? (H = 1, C = 12, O = 16)
A
C 4H 8O2
B
C 4H 8O3
C
C 6H 10O5
D
C 6H 12O6
E
C 12H 22O11
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 #36104)
Chemistry
WAEC / WASSCE 1990
Stoichiometry, Mole Concept & Volumetric Analysis
MO and X 2O represent the formula of oxides of elements M and X respectively . If M and X should combine to form a separate compound, what would be the formula of the compound?
A
MX2
B
M2X
C
MX
D
M3X2
E
MX3
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 #36105)
Chemistry
WAEC / WASSCE 1990
Air & Environmental Chemistry
Which of the following pollutants is biodegradable ?
A
Sewage
B
Plastics
C
Metal scrape
D
Lead compounds
E
Hydrogen sulphide
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 #36106)
Chemistry
WAEC / WASSCE 1990
Oxidation, Reduction & Redox Reactions
In the reaction represented by the equation; 2FeCI3 + SO2 + 2H2O → 2FeCL2 + H2SO4 + 2HCI the oxidation number of sulphur changes from
A
+2 to + 6
B
+ 4 to + 6
C
0 to + 6
D
- 2 to + 4
E
+2 to + 4
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 #36107)
Chemistry
WAEC / WASSCE 1990
Water, Solutions & Solubility
Which of the following equations represents the reaction leading to the removal of permanent hardness of water?
A
Ca(HCO 3)2 → CaCO3 + H2O + CO2
B
MgSO4 + Na 2CO3 + Na 2SO
C
Ca(OH) 2 + 2HCI → CaCI 2 + 2H 2O
D
Ca(HCO3)2 + Ca(OH)3 → 2CaCO3 + 2H2O
E
MgSO4 + BaCI2 → MgCI2 + BaSO4
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 #36108)
Chemistry
WAEC / WASSCE 1990
Metals, Transition Elements & Extraction
The following alloys contain copper except
A
magnalium
B
duralumn
C
bronze
D
brass
E
type metal
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 #36109)
Chemistry
WAEC / WASSCE 1990
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
How many mole of AgNO\(_3\) are there in 500cm\(^3\) of 0.01M AgNO\(_3\) solution?
A
0.005 mole
B
0.05 mole
C
0.5 mole
D
5 moles
E
1 mole
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Given:
V = 500 cm\(^3\)
C = 0.01M
n = ?
The relationship among the three parameters is n = \(\frac{CV}{1000}\)
n = \(\frac{0.01\times 500}{1000}\)
n = 0.005 mole
Source: Myschool Past Questions Archive (Record #36110)
Chemistry
WAEC / WASSCE 1990
Acids, Bases, pH & Salts
Which of the following statements explains why tetraoxosulphate (IV) acid is reqarded as a strong acid?
A
Tetraoxosulphate (IV) acid is dibasic
B
the acid is concentrated
C
the acid is complately ionized in aqueous solution
D
tetraxosulphate (IV) ions are very reactive
E
the acid is highly corrosive
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 #36111)
Chemistry
WAEC / WASSCE 1990
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Which of the following is not correct of glucose and fructose?They
A
are structural isomers
B
reduce fehling's solution
C
can be obtained by the hydrolysis of starch
D
are readily fermented by enzymes
E
are soluble in water
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 #36112)
Chemistry
WAEC / WASSCE 1990
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
To what temperature must a gas be raised from 273K in order to double both its volume and pressure?``
A
298k
B
300k
C
546k
D
819k
E
1092k
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
Given:
T\(_1\) = 273K V\(_1\) = X P\(_1\) = Y → Let x and y represent the initial volume and initial pressure respectively.
T\(_2\) = ? V\(_2\) = 2X P\(_2\) = 2Y → Since the volume and pressure were doubled.
Using the formula, \(\frac{P_1 V_1}{T_1}\) = \(\frac{P_2 V_2}{T_2}\)
T\(_2\) = \(\frac{P_2 V_2 T_1}{P_1 V_1}\)
= \(\frac{2Y\times 2X \times 273}{Y\times X}\)
= 2 X 2 X 273
T\(_2\)= 1092K
Source: Myschool Past Questions Archive (Record #36113)
Chemistry
WAEC / WASSCE 1990
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following explains why trioxonitrate (V) acid is not used for preparing hydrogen from metals?
A
it is volatile
B
it is strongly oxidizing
C
it forms a layer of oxide on the metal
D
trioxonitrate (V) salts are soluble in water
E
it renders the metals passive
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 #36114)
Chemistry
WAEC / WASSCE 1990
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following is normally used for drying ammonia gas?
A
Concentrated tetraoxonitrate (Vl) acid
B
Calcium oxide
C
anhydrous calcium chloride
D
phosphorus (V) oxide
E
anhydrous copper (ll) tetraoxosulphate (VI)
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 #36115)
Chemistry
WAEC / WASSCE 1990
Atomic Structure, Orbitals & Nuclear Chemistry
Nuclear reactions can be used in the following except
A
gauging the thickness of objects
B
making atomic bombs
C
curing cancer
D
generating electricity
E
purifying water
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 #36116)