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Chemistry
WAEC / WASSCE 2016
Periodic Table & Periodicity
The energy which accompanies the addition of an electron to an isolated gaseous atom is
A
Atomization
B
Electronegativity
C
Electron affinity
D
Ionization
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 #45185)
Chemistry
WAEC / WASSCE 2016
Acids, Bases, pH & Salts
Solution
An aqueous solution of (NH4)2 SO4 is
A
Acidic
B
Alkaline
C
Amphoteric
D
Neutral
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Ammonium sulphate is an ACIDIC SALT. This is because it is formed when sulphuric acid reacts with ammonia. Since, sulphuric acid is a strong acid and ammonia is a weak base, so it gets acidic in nature.
Source: Myschool Past Questions Archive (Record #45188)
Chemistry
WAEC / WASSCE 2016
Chemical Energetics & Thermochemistry
When NH4Cl(s) is dissolved in water, the container feels cold to touch. This implies
A
The process is endothermic
B
The process is exothermic
C
NH4Cl forms a saturated solution
D
NH4Cl is highly soluble in 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 #45190)
Chemistry
WAEC / WASSCE 2016
Acids, Bases, pH & Salts
The pH of four solutions M,N,Q and R are 2,6,8 and 11 respectively.
Which of the following deductions about the solutions is correct?
A
The pH of N is increased when the solution is diluted
B
The pH of Q is increased when the solution is evaporated
C
M is the most alkaline solution
D
R is the most acidic solution
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 #45192)
Chemistry
WAEC / WASSCE 2016
Acids, Bases, pH & Salts
Consider the following reaction equation
H3O+(aq) + OH(aq) \(\rightarrow\) 2H2O(1)
The reaction represents
A
Esterification
B
Hydrolysis
C
Neutralization
D
Redox
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 #45195)
Chemistry
WAEC / WASSCE 2016
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
The refreshing characteristic taste of fizzy drinks is due ot the presence of
A
Carbon(IV)oxide
B
Glucose
C
Hydrogen
D
Sodium Citrate
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 #45196)
Chemistry
WAEC / WASSCE 2016
Reaction Rates & Chemical Equilibrium
Chemical equilibrium is attained when
A
All the reactants have been completely used up
B
The reaction goes to completion
C
The concentration of reactants and products remain constant
D
The concentration of reactants and products are equal
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 #45201)
Chemistry
WAEC / WASSCE 2016
Reaction Rates & Chemical Equilibrium
Solution
Which of the following factors will affect the rate of the reaction represented by the following equation?
2HCl(aq) + CaCO3(s) \(\rightarrow\) CaCl2(aq) + H2O(1) + CO2(g)
I. Pressure
II.Concentration
III. Nature of reactants
IV. Temperature
A
I and II only
B
II, III and IV only
C
I, II and III only
D
I, II. III and IV
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
All others except pressure would affect the equilibrium of the system.
If only the product is gaseous and none of the reactants are gaseous, then pressure will not have a significant effect on the rate of reaction because the pressure change only affects the concentration of gaseous species, and since no reactants are in the gas phase, there's no change in their concentration to influence the reaction rate.
Source: Myschool Past Questions Archive (Record #45202)
Chemistry
WAEC / WASSCE 2016
Water, Solutions & Solubility
Solution
On evaporation to dryness, 350cm\(^3\) of saturated solution of salt Z gave 55.5g of salt. What is the solubility of the salt? [Z = 101]
A
1.57 moldm-3
B
3.14 moldm-3
C
6.28 moldm-3
D
12.56 moldm-3
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Saturated solution = 350cm\(^3\)
mass of salt Z in saturated solution = 55.5g
Number of moles of salt = \(\frac{55.5}{101}\) = 0.55mole
If 350cm\(^3\) of solution contains 0.55mole
1000cm\(^3\) will contain \(\frac{1000 \times 0.55}{350}\) = 1.57moldm\(^{-3}\)
Alternatively, you can use the formula for solubility which is:
Solubility = \(\frac{mass of solute}{Molar mass of solute}\times\frac{1000}{Volume of solvent}\)
= \(\frac{55.5}{101}\times\frac{1000}{350}\)
= 1.571 moldm\(^{-3}\)
Source: Myschool Past Questions Archive (Record #45203)
Chemistry
WAEC / WASSCE 2016
Acids, Bases, pH & Salts
Which of the following salts when dissolved in water will form a solution that will change blue litmus to red?
A
CH3COONa
B
NH4Cl
C
NaCl
D
KCl
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 #45204)
Chemistry
WAEC / WASSCE 2016
Chemical Bonding & Intermolecular Forces
Which of the following bonds are broken when ethanol is boiled?
I. Covalent bonds
II. Ionic bonds
III. Hydrogen bonds
A
I only
B
II only
C
III only
D
I, II, III
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 #45205)
Chemistry
WAEC / WASSCE 2016
Organic Chemistry II: Functional Groups, Polymers & Biomolecules
A compound with molecular formula CH2O2 is
A
A Carbohydrate
B
A Carboxylic acid
C
An alkanol
D
An ester
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 #45206)
Chemistry
WAEC / WASSCE 2016
Stoichiometry, Mole Concept & Volumetric Analysis
The quality of electricity required to discharge 1 mole of univalent ion is
A
9600C
B
48250C
C
96500C
D
193000C
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 #45207)
Chemistry
WAEC / WASSCE 2016
Oxidation, Reduction & Redox Reactions
Chlorine water is used as a bleaching agent because it is
A
An acidic solution
B
An alkaline solution
C
An oxidizing agent
D
A reducing agent
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 #45208)
Chemistry
WAEC / WASSCE 2016
Electrolysis & Electrochemical Cells
Which of the following substances is a non-electrolyte?
A
H2SO4
B
CH3COOH
C
C6H12O6
D
NH4Cl
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 #45209)