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 20101–20115 of 29821 verified questions
Sort by:
Chemistry
WAEC / WASSCE 1999
Kinetic Theory of Matter & Gas Laws
Which of the following movements can be described as random motion?
A
wheelbarrow being pushed
B
car travelling on a straight line
C
Gas molecules colliding in a flask
D
Planets going round the sun
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 #36694)
Chemistry
WAEC / WASSCE 1999
Kinetic Theory of Matter & Gas Laws
Equal volumes of CO2 cnd CO at s.t.p have the same
A
mass
B
density
C
rate of diffusion
D
number of molecules
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 #36695)
Chemistry
WAEC / WASSCE 1999
Kinetic Theory of Matter & Gas Laws
Gas molecules are said to be perfectly elastic because
A
they collide without loss of energy
B
they move about in straight lines
C
the distances between them are negligible
D
the volume occupied by them is negligible
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 #36696)
Chemistry
WAEC / WASSCE 1999
Kinetic Theory of Matter & Gas Laws
Solution
What volume of hydrogen is produced at s.t.p. When 2.60 g of zinc reacts with excess HCI according to the following equation? Zn(s) + 2HCI(aq) → ZnCI 2(aq) + H2(g) [Zn = 65; 1 mole of a gas occupies 22.4dm3 at s.t.p]
A
0.040dm 3
B
0.896dm 3
C
5.82dm 3
D
8.62dm 3
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Zn + 2HCI → ZnCI2 + H2; 65g of Zn produces 22.4 dm3 of H2; .: 2.6g of Zn will produce = 2.6/65 x 22.4 = 0.896 dm3
Source: Myschool Past Questions Archive (Record #36697)
Chemistry
WAEC / WASSCE 1999
Atomic Structure, Orbitals & Nuclear Chemistry
Solution
Helium is preferred to hydrogen in filling balloons because hydrogen
A
is inflammable
B
is diatomic
C
exhibits isotopy
D
is a component of water
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Helium is a colorless, non-toxic, non-flammable gas that is lighter than air. When balloons are filled with helium, they will float.
Source: Myschool Past Questions Archive (Record #36700)
Chemistry
WAEC / WASSCE 1999
Kinetic Theory of Matter & Gas Laws
Solution
30cm3 pf hydrogen at s.t.p combine with 20cm3 of oxygen to form steam according to the following equation 2H2(g) + O2(g) → 2H2O(g).
Calculate the total volume of the gaseous mixture at the end of the reaction
A
50cm3
B
35cm3
C
30cm3
D
25cm3
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
2H\(_2\)(g) + O\(_2\)(g) → 2H\(_2\)O(g).
2 volumes of H\(_2\)(g) and 1 volume of O\(_2\)(g) produced 2 volumes of H\(_2\)O\(_2\)
ratio of reacting volumes
30cm\(^3\) + 15cm\(^3\) → 30cm\(^3\)
30cm\(^3\) of Hydrogen requires 15cm\(^3\) of oxygen to produce 30cm\(^3\) of water.
Excess oxygen: 20cm\(^3\) – 15cm\(^3\) = 5cm\(^3\)
Total volume of gaseous mixture: 5cm\(^3\) of Oxygen + 30cm\(^3\) of Water = 35cm\(^3\)
Source: Myschool Past Questions Archive (Record #36701)
Chemistry
WAEC / WASSCE 1999
Chemical Energetics & Thermochemistry
An exothermic reaction is one which involves
A
attainment of dynamic equilibrium
B
loss of heat to the surrounding
C
evolution of gas as it proceeds
D
positive change in value of enthalpy
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 #36705)
Chemistry
WAEC / WASSCE 1999
Acids, Bases, pH & Salts
Which of the following is an acid salt?
A
NH4CI
B
MgSO4 7H2O
C
CH3COONa
D
NaHCO3
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 #36706)
Chemistry
WAEC / WASSCE 1999
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following compounds dissolves in water to form a solution with pH below 7?
A
Sodium tetraoxosulphate (VI)
B
Potassium hydroxide
C
Ammonium chloride
D
Sodium trioxocarbonate (IV)
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 #36707)
Chemistry
WAEC / WASSCE 1999
Stoichiometry, Mole Concept & Volumetric Analysis
If the solubility of KHCO3 is 0.40 mole dm-3 at room temperature , calculate the mass of KHCO3 in 100dm3 of the solution at this temperature. [KHCO3 = 100hmol]
A
4.0g
B
10.0g
C
40.0g
D
100.0g
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 #36713)
Chemistry
WAEC / WASSCE 1999
Water, Solutions & Solubility
The property of calcium chloride which makes it useful as a drying agent is that it is
A
ionic
B
deliquescent
C
a strong electrolyte
D
a normal salt
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 #36714)
Chemistry
WAEC / WASSCE 1999
Reaction Rates & Chemical Equilibrium
Which of the following lowers the activation energy of a chemical reaction?
A
Freezing mixture
B
Reducing agent
C
Water
D
Catalyst
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 #36715)
Chemistry
WAEC / WASSCE 1999
Reaction Rates & Chemical Equilibrium
Consider the reaction represented by the following equation: H2(g) + 12(g) → 2HI(g). The number of effective collisions of molecules of the reactants decreases as
A
the temperature is raised
B
the pressure increased
C
the volume of the system is increased
D
a catalysty is intoduced into the system
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 #36717)
Chemistry
WAEC / WASSCE 1999
Reaction Rates & Chemical Equilibrium
What will be the effect of increase in pressure on the following system at equilibrium? 2NH2(g) N2(g) + 3H2(g)
A
Activation energy will decrease
B
the forward reaction will be favoured
C
the concentration of ammonia will increase
D
the reaction will go to completion
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 #36718)
Chemistry
WAEC / WASSCE 1999
Oxidation, Reduction & Redox Reactions
Which of the following is not correct about oxidation number convention? The oxidation number of a/an
A
element in the free state is zero
B
monatomic ion is equal to its charge
C
alkali meta like sodium in its compounds is + 1
D
atom of a diatomic molecules is + 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 #36719)