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Chemistry
WAEC / WASSCE 2004
Oxidation, Reduction & Redox Reactions
The reaction that takes place at the cathode when an aqueous solution of NaCI is electrolysed using carbon electrodes is
A
2H+2(g) + 2e- → H2(g)
B
Na+2(g) + e- → Na(s)
C
4OH- → 2H2O(l) + O2(g) +4e-
D
2CI- → CI2(g) + 2e-
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 #37049)
Chemistry
WAEC / WASSCE 2004
Acids, Bases, pH & Salts
What of the following pairs of acid and base will produce a solution with pH less than 7 at equivalence point?
A
HNO3 and NaOH
B
H2SO4 and KOH
C
HCI and Mg(OH) 2
D
HNO 3 and KOH
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 #37050)
Chemistry
WAEC / WASSCE 2004
Stoichiometry, Mole Concept & Volumetric Analysis
WHICH OF THE FOLLOWING SALTS IS READILY SOLUBLE IN WATER?
A
PbCI2
B
Pb(NO 3) 2
C
PbSO4
D
PbCO 3
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 #37051)
Chemistry
WAEC / WASSCE 2004
Reaction Rates & Chemical Equilibrium
Solution
Which of the following factors that affect the rate of chemical reactions can be explained in terms of the collision theory? l. concentration ll. pressure lll. temperature lV catalyst
A
l and ll only
B
l, ll and lll only
C
l and lll only
D
l, II, lll and IV only
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The factors that affect reaction rates are:
surface area of a solid reactant.
concentration or pressure of a reactant.
temperature.
nature of the reactants.
presence/absence of a catalyst
Source: Myschool Past Questions Archive (Record #37052)
Chemistry
WAEC / WASSCE 2004
Nature of Matter & Separation Techniques
An orange drink concentrate is suspected to contain traces of poisonous green dye and a harmless dye having the same boiling point. Which of the following techniques is most suitable for isolating the dyes?
A
Fractional distillation
B
Paper chromatography
C
Coagulation
D
Recrystallization
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 #37053)
Chemistry
WAEC / WASSCE 2004
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
If 60 cm3 of gas is heated from 27oC TO 50oC, what is the new volume of the gas at constant pressure?
A
32.4cm 3
B
55.7cm3
C
64.6cm3
D
111.1cm3
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
V1 = 60cm T1 = 273 +27 = 300K
T2 = 273 + 50 = 323KV2 = ?
V1/T1 = V2/T2 .: V2 = V1T 2/T1 = 60 x 323/300 = 19380/300 = 64.6cm3
Source: Myschool Past Questions Archive (Record #37054)
Chemistry
WAEC / WASSCE 2004
Electrolysis & Electrochemical Cells
Consider the cell represented below: Zn/Zn2+(aq) // Cu2+(aq) / Cu(s). Which of the following statements is correct about the cell
A
Zn is oxidized to Zn2+
B
Cu is oxidized to Cu2+
C
It is an electrolytic cell
D
each single line represents a salt bridge
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 #37055)
Chemistry
WAEC / WASSCE 2004
Stoichiometry, Mole Concept & Volumetric Analysis
When ammonium trioxocarbonate (IV) solution is added to separate solutions of calcium, zinc and sodium salt precipitate could be formed in the case of
A
calcium only
B
zinc only
C
calcium and znic only
D
sodium and zinc only
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 #37056)
Chemistry
WAEC / WASSCE 2004
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
The condensation of several amino acid molecules gives
A
long chain alkanoic acids
B
secondary alkanols
C
alkanoates
D
proteins
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 #37057)
Chemistry
WAEC / WASSCE 2004
Chemical Energetics & Thermochemistry
Solution
Which of the following statements is true of an endothermic reaction? I. Heat is absorbed from the surrounding II. The heat content of the products is more than that of the reactants III. The enthalpy change is positive IV. The surrounding is at a lower temperature than the system.
A
l only
B
l and ll only
C
l,ll and lll only
D
l, ll, lll and lV
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
For an endothermic reaction; heat flows from the surroundings to the system( but that doesn't make the surroundings to be at a lower temperature than the system) meaning the surroundings are at a higher temperature than the system. The system's enthalpy change, i.e. \DeltaH is positive or > 0. The heat content of the product is more than that of the reactant.
Source: Myschool Past Questions Archive (Record #37058)
Chemistry
WAEC / WASSCE 2004
Oxidation, Reduction & Redox Reactions
What is the change in the oxidation number of 1- in the reaction represented by the following equation? 51 -1(aq) + 6H+(aq) + 1O-3(aq) → 312(g) + 3H2O(l)
A
-5 to -3
B
-1 to 0
C
+ 5 to + 0
D
-1 to + 2
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 #37059)
Chemistry
WAEC / WASSCE 2004
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
The key factor to be considered in siting a chemical industry is
A
favourable climatic conditions
B
the availability of space to store raw materials
C
its nearness to other industrial establishments
D
its nearness to the source of raw materials
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 #37060)
Chemistry
WAEC / WASSCE 2004
Reaction Rates & Chemical Equilibrium
Which of the following reactions will be affected by change in pressure at equilibrium?
A
X(g) + Y(g) ⇌ W(g) + Z(g)
B
X(g) + 2Y(g) ⇌W(g) + Z(g)
C
2X(g) ⇌ W(g) + Z(g)
D
2Y(g) ⇌ W(g) + Z(g)
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 #37061)
Chemistry
WAEC / WASSCE 2004
Organic Chemistry I: Hydrocarbons & Crude Oil
Solution
WHICH OF THE FOLLOWING PETROLEUM FRACTIONS YIELDS VASELINE AND PARAFFIN WAX ON REDISTILLATION?
A
DIESEL OIL
B
LUBRICATION OIL
C
PETROL
D
KEROSENE
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Lubricating oil, a fraction of crude oil on re-distillation produces the following: vaseline, fuel oil, paraffin wax, etc
Source: Myschool Past Questions Archive (Record #37062)
Chemistry
WAEC / WASSCE 2004
Organic Chemistry I: Hydrocarbons & Crude Oil
Solution
What is the product Cx Hy in the following equation? \(C_{10}H_{22}\) → \(C_{8}H_{18}\) + CxHy
A
butene
B
octane
C
ethene
D
decane
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
\(C_{10}H_{22}\) → \(C_{8}H_{18}\) + CxHy
\(C_{10}H_{22}\) → \(C_{8}H_{18}\) + (\(C_2H_4\)) ⇒⇒ Ethene.
Source: Myschool Past Questions Archive (Record #37063)