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Chemistry
WAEC / WASSCE 2007
Reaction Rates & Chemical Equilibrium
Solution
What process is illustrated below? S(s) ⇌H2O⇌ S (aq)
A
Decomposition of a solid
B
Melting of a solid
C
Formation of saturated solution of a solid
D
Sublimation of a solid
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
From the given equation:
\(S_{(s)} ⇌ S_{(aq)}\) (in the presence of (\(H_2O\))
The solid form has changed to an aqueous solution upon dissolution in water. Due to the presence of the reversible reaction arrow ⇌, the solution (aqueous) formed is saturated, this is because a saturated solution is an equilibrium system
Source: Myschool Past Questions Archive (Record #37201)
Chemistry
WAEC / WASSCE 2007
Stoichiometry, Mole Concept & Volumetric Analysis
A solution of a salt X reacts with AgNO3 solution to give white precipitate which dissolves in excess aqueous ammonia. X contains
A
CI-
B
Pb 2+
C
SO 2-
D
Zn2+
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 #37202)
Chemistry
WAEC / WASSCE 2007
Reaction Rates & Chemical Equilibrium
Consider the reaction represented by the following equation: N2(g) + 3H2(g) ⇌ 2NH3(g); ∆H = - 92kJmol1. Finely divided iron is used as catalyst in the reaction in order to
A
lower the value of ∆H
B
increase the time for attainment of equilibrium
C
shorten the time for attainment of equilibrium
D
decrease the yield of ammonia
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 #37203)
Chemistry
WAEC / WASSCE 2007
Electrolysis & Electrochemical Cells
Which of these cell notations is the correct representation of a Daniell cell?
A
Zn(s) / Zn2+(aq) // Cu2+(aq)/Cu(s)
B
Cu(s) / CU2+(aq) // Zn2+(aq) / Zn(s)
C
Zn2+(aq) / Zn(s) // Cu2+(aq) /Cu(s)
D
Cu2+(aq) / Cu(s) // Zn(s) / Zn2+(aq)
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 #37206)
Chemistry
WAEC / WASSCE 2007
Oxidation, Reduction & Redox Reactions
Solution
What is the oxidation number of chromium in K2CrO4?
A
+1
B
+2
C
+4
D
+6
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
K2CrO4 (O.N of K) X 2 + O.N of Cr + (O.N of oxygen) X 4 = 0
1 X 2 + X + -2 X 4 = 0
2 + x + -8 = 0
2 + x - 8 = 0
x = 8 - 2 = + 6
Source: Myschool Past Questions Archive (Record #37230)
Chemistry
WAEC / WASSCE 2007
Electrolysis & Electrochemical Cells
What product is formed at the cathode during the electrolysis of concentrated sodium chloride solution using carbon electrodes?
A
Chlorine
B
Hydrogen
C
Oxygen
D
Sodium
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 #37231)
Chemistry
WAEC / WASSCE 2007
Organic Chemistry I: Hydrocarbons & Crude Oil
Which of the following substances is suitable solvent for perfumes?
A
Benzene
B
Ethanol
C
Turpentine
D
Water
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 #37232)
Chemistry
WAEC / WASSCE 2007
Stoichiometry, Mole Concept & Volumetric Analysis
The complete hydrogenation of C 6
H 6 in the presence of nicked catalyst at 200oC gives
A
C6H8
B
C 6H10
C
C 6H 12
D
C 6H 14
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 #37233)
Chemistry
WAEC / WASSCE 2007
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following pairs of substances can be distinguished by use of NaHCO3 solution?
A
CH 3CH2OH and HCOOCH3
B
CH 3CH2OH and CH3COOH
C
CH3COOH and HCOOH
D
CH 3CH2OH and CH3OH
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 #37234)
Chemistry
WAEC / WASSCE 2007
Organic Chemistry I: Hydrocarbons & Crude Oil
Alkenes undergo the following reactions except
A
addition
B
hydration
C
polymerization
D
substitution
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 #37235)
Chemistry
WAEC / WASSCE 2007
Stoichiometry, Mole Concept & Volumetric Analysis
Hydrocarbons which react with ammoniacal copper (l) chloride solution conform to the general molecular formula
A
CnH2n
B
CnH2n
C
CnH2n+2
D
CnH2n-2
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 #37236)
Chemistry
WAEC / WASSCE 2007
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following compounds reacts readily with sodium to liberate hydrogen?
A
CH3CH2CH3
B
CH3COOH
C
CH3 CH2CHO
D
CH3 CH(OH)CH3
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 #37239)
Chemistry
WAEC / WASSCE 2007
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
Glucose reduces Fehling's solution on warming to
A
copper (l) oxide
B
copper (ll) oxide
C
copper (l) chloride
D
copper (ll) hydroxide
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 #37244)
Chemistry
WAEC / WASSCE 2007
Metals, Transition Elements & Extraction
from the following ores is iron extracted? I. Haematite ll. Bauxite III. Magnetite IV. Cassiterite
A
l and ll only
B
l and lll only
C
l, ll and lll only
D
l, ll, lll and lV
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 #37250)
Chemistry
WAEC / WASSCE 2007
Nature of Matter & Separation Techniques
Which of the following methods can be used to separate a mixture of two miscible liquids with different boiling points?
A
Decantation
B
Distillation
C
Evaporation
D
Filtration
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 #37251)