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Chemistry
WAEC / WASSCE 2002
Atomic Structure, Orbitals & Nuclear Chemistry
Which of the following elements has a ground state electronic configuration with an incomplete penultimate shell?
A
Iron
B
Sodium
C
Aluminium
D
Calcium
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 #39954)
Chemistry
WAEC / WASSCE 2002
Atomic Structure, Orbitals & Nuclear Chemistry
The conclusion from Rutherford's alpha-scattering experiment is that
A
atoms are mostly empty space with a small nucleus
B
emissions from radioactive substances consist of three main components
C
there is nuclear pull on orbital electrons
D
electrons are deflected by both magnetic and electric fields
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 #39955)
Chemistry
WAEC / WASSCE 2002
Atomic Structure, Orbitals & Nuclear Chemistry
An element Y has the electronic configuration 1s22s22p6623p4. To what period does it belong in the periodic table?
A
3
B
4
C
5
D
6
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 #39961)
Chemistry
WAEC / WASSCE 2002
Stoichiometry, Mole Concept & Volumetric Analysis
If a metal R forms a compound with the formula R(NO3)2 , the formula of its tetraoxosulphate (IV) is
A
R(SO4)2
B
RSO4
C
R2SO4
D
R2(SO4)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 #39964)
Chemistry
WAEC / WASSCE 2002
Periodic Table & Periodicity
Which of the following decreases when a given mass of gas is compressed to half its initial volume?
A
Average intermolecular distance
B
Frequency of collisions
C
Number of molecules present
D
Atomic radius of each particle
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 #39965)
Chemistry
WAEC / WASSCE 2002
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
What volume of hydrogen will be produced if 100cm3 of ammonia is completely decomposed at constant temperature and pressure? The equation for reaction is 2NH3(g) → N2(g) + 3H2(g)
A
50cm3
B
150cm3
C
200cm3
D
300cm3
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
According to the equation 2NH3 → N3 + 3H2
2 x 22400cm3 of ammonia will produce
3 x 22400cm3 of hydrogen
If 100cm3 of NH3 is used.
:. H2 volume = \(\frac{100}{2x22400} x 3x22400
=150cm3
Source: Myschool Past Questions Archive (Record #39966)
Chemistry
WAEC / WASSCE 2002
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
Calculate the mass of chlorine gas which occupies a volume of 1.12 dm\(^3\) a volume of 1.12 dm\(^3\) at s.t.p [Cl = 35.5, 1 mole og gas occupies 22.4 dm\(^3\) at s. t. p ]
A
1.80g
B
3.55g
C
7.10g
D
15.50g
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
1 mole Cl\(_2\) occupy 22.4dm\(^3\)
i.e 2 x 35.5 → 22.4 ; x → 1. 12
:. x = \(\frac{1.12}{22.4}\) x 2 x 35.5 = 3.55
Source: Myschool Past Questions Archive (Record #39977)
Chemistry
WAEC / WASSCE 2002
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
Determine the mass of sulphur (IV) oxide obtained when 91.0g of oxygen reacts completely with sulphur according to the following equation: S(s) + O\(_2\)(g) → SO\(_2\)(g) [S = 32; O = 16]
A
123g
B
139g
C
155g
D
182g
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
S + O\(_2\) → SO\(_2\).
According to the equation 32g of O\(_2\) produced 64g of SO\(_2\)
therefore 91g of O2 will produce yg of SO2
y = \(\frac{91 * 64}{32}\)
y = 182g of SO\(_2\)
Source: Myschool Past Questions Archive (Record #39983)
Chemistry
WAEC / WASSCE 2002
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
The gas given off when NH4 Cl is heated with an alkali is
A
H2
B
Cl2
C
N2
D
NH3
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
NH₄Cl + NaOH → NH₃↑ + NaCl + H₂O
Ammonium chloride (NH₄Cl) reacts with an alkali like sodium hydroxide (NaOH) or calcium hydroxide (Ca(OH)₂) when heated, releasing ammonia gas.
Source: Myschool Past Questions Archive (Record #39984)
Chemistry
WAEC / WASSCE 2002
Water, Solutions & Solubility
A major factor considered in selecting a suitable method for preparing a simple salt is its
A
crystalline form
B
melting point
C
reactivity with dilute acids
D
solubility in water
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 #39997)
Chemistry
WAEC / WASSCE 2002
Water, Solutions & Solubility
A substance is said to be hygroscopic if it absorbs
A
water from the atmosphere to form a solution
B
heat from the surrounding
C
carbon (IV) oxide from the atmosphere
D
moisture from the atmosphere without dissolving
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 #40004)
Chemistry
WAEC / WASSCE 2002
Stoichiometry, Mole Concept & Volumetric Analysis
Which of the following substances increases in mass when heated in air?
A
Sodium chloride
B
lodine crystals
C
Magnesium ribbon
D
Copper (ll) oxide
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 #40010)
Chemistry
WAEC / WASSCE 2002
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
Calculate the mass of sodium hydroxide in 5.00 dm3 of a 0.125 mol dm-3 solution. [NaOH = 40 g mol-1]
A
0.0156 g
B
0.625 g
C
1.00 g
D
25.0 g
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
1 mole of NaOH per dm3 has a mass of 40g.
mass of NaOH in 0.125mole
= 0.125 x 40 = 5g.
mass in 5.00 dm3 of the solution.
= 5 x 5 = 25.0g.
Source: Myschool Past Questions Archive (Record #40011)
Chemistry
WAEC / WASSCE 2002
Acids, Bases, pH & Salts
Which of the following salt solutions will have a pH greater than 7?
A
NaCI(aq)
B
Na2CO3(aq)
C
Na2SO4(aq)
D
NaHSO4(aq)
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 #40012)
Chemistry
WAEC / WASSCE 2002
Reaction Rates & Chemical Equilibrium
What is the expression for the equilibrium constant (Kc) for the following reaction? N2(g) + O2(g) ⇌ 2NO(g)
A
\(\frac{[NO^2]}{[N^2] + [O^2]}\)
B
\(\frac{[2NO]^2}{[N_2][O_2]}\)
C
\(\frac{[N_2] + [O_2]}{2[NO]^2}\)
D
\(\frac{[NO]^2}{[N_2][O_2]}\)
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 #40019)