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Chemistry
NECO SSCE 2001
Matter & Separation Techniques
Which metal will dissolve in aqueous sodium hydroxide?
A
aluminium
B
copper
C
iron
D
sikeer
E
tin
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 #43334)
Chemistry
NECO SSCE 2001
Stoichiometry & Mole Concept
in any chemical reaction, the total mass of products is always equal to that of the reactants.
This Is statement of the law of:
A
conservation of matter.
B
Constant composition
C
definite proportions.
D
multiple proportions.
E
reciprocal proportions.
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 #43335)
Chemistry
NECO SSCE 2001
Acids, Bases, and Salts
Solution
The alloy used for welding and plumbing contains
A
aluminum and copper.
B
copper and tin
C
iron and aluminum.
D
lead and antimony.
E
lead and tin.
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
The primary alloy for plumbing and low-temp welding (soldering) is solder, typically a tin-lead alloy (like 63% tin, 37% lead) for its low melting point, but modern plumbing often uses lead-free solder (tin-silver-copper) or brazing alloys, while actual high-heat welding uses various filler alloys like steel, bronze, or aluminum, depending on the base metal.
Source: Myschool Past Questions Archive (Record #43336)
Chemistry
NECO SSCE 2001
Acids, Bases, and Salts
Solution
Which compound is a product of the hydrolysis of the of CH\(_3\)COOC\(_3\)H\(_7\) with aqueous sodium hydroxide?
A
CH3COONa
B
CH3COONaCCH3OH
C
CH3OH
D
C2H5OH
E
C3H7COONa
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
The reaction is an example of ester hydrolysis, where an ester (in this case, ethyl acetate) reacts with water in the presence of a base (NaOH) to break down into an alcohol and a carboxylate salt.
Reaction: The reaction can be represented as CH\(_3\)COOC\(_3\)H\(_7\) + NaOH → CH\(_3\)COONa + C\(_3\)H\(_7\)OH
Source: Myschool Past Questions Archive (Record #43337)
Chemistry
NECO SSCE 2001
Acids, Bases, and Salts
On exposure to hydrogen sulphide, moist lead (II) ethanoate paper turns
A
black
B
blue
C
green
D
white
E
yellow
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 #43338)
Chemistry
NECO SSCE 2001
Atomic Structure and Periodic Table
The maximum number of electrons that can occupy the shell having a principal quantum number of 3 is
A
3
B
9
C
10
D
18
E
32
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 #43339)
Chemistry
NECO SSCE 2001
Stoichiometry & Mole Concept
Solution
What is the ratio of the rate of diffusion of carbon(IV) oxide to that of propane, under the same conditions? [H = 1; C= 12; 0= 161
A
1:01
B
1:10
C
2:01
D
2:03
E
3:01
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
The ratio of the rate of diffusion of carbon(IV) oxide (CO\(_2\)) to that of propane (C\(_3\)H\(_8\)) under identical conditions is 1:01 (or 1:1).
First, we determine the relative molecular mass (M) of each gas using the provided atomic masses (H = 1, C = 12, O = 16).
- Carbon(IV)oxide, CO\(_2\) = 12 + (16 X 2) = 44
- Propane, C\(_3\)H\(_8\) = (12 X 3) + (1 X 8) = 44
Graham's Law states that under the same conditions of temperature and pressure, the rate of diffusion of a gas (R) is inversely proportional to the square root of its molar mass (M).
\(\frac{R_CO2}{R_C3H8}\) = \(\sqrt{\frac{M_{C3H8}}{M_{CO2}}}\)
\(\frac{R_CO2}{R_C3H8}\) = \(\sqrt{\frac{44}{44}}\) = 1
Therefore, the ratio is exactly 1:1 (written as 1:01 in the options).
Source: Myschool Past Questions Archive (Record #43340)
Chemistry
NECO SSCE 2001
Stoichiometry & Mole Concept
Solution
How much sodium hydroxide is required to make 250 cm3 of 0.1 molar solution? Na=23; 0=16; H=1]
A
10.0 g
B
4.0g
C
2.0 g
D
1 .0g
E
0.1 g
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
no of moles of Na = molar concentration X volume
= 0.1 x \(\frac{250}{1000}\) = 0.025
no of moles = \(\frac{m}{M}\)
mass = no of mles x molar mass = 0.025 x 40 = 1.0g ( molar mass of NaOH = 40g/mol)
Source: Myschool Past Questions Archive (Record #43341)
Chemistry
NECO SSCE 2001
Electrochemistry and Redox
Solution
The oxidation number of X in \(XO_{4}^{3-}\) is
A
1
B
-2
C
3
D
4
E
5
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
The oxidation number of O is 2-
Therefore, let the oxidation number of X be a
a + (-2 x 4) = -3
a - 8 = -3
a = -3+8
a = 5
Source: Myschool Past Questions Archive (Record #43342)
Chemistry
NECO SSCE 2001
Matter & Separation Techniques
The high boiling point of hydrogen fluoride can be explained in terms of
A
covalent bonds.
B
dative bonds.
C
dipole-dipole bonds.
D
electrovalent (ionic) bonds
E
hydrogen bonds.
medium Difficulty
Verified Correct Answer: Option E
Chemical Principles & Mechanism
No expanded working has been attached for this question yet. The verified answer is Option E.
Source: Myschool Past Questions Archive (Record #43343)
Chemistry
NECO SSCE 2001
Kinetics, Energetics and Equilibrium
Which of the following is TRUE of a catalyst? I. it alters the activation energy of a reaction
II. it is effective in a reaction but cannot initiate a reaction
III, it affects the equilibrium of a reversible reaction
IV. it affects the overall reaction
A
I and II only
B
I, II and III only
C
II and III only
D
II, II and IV only
E
III and IV only
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 #43344)
Chemistry
NECO SSCE 2001
Matter & Separation Techniques
White is NOT a property of metals?
A
ductile:
B
malleable
C
conduct heat and electricity
D
have many oxidation states
E
high melting points anti boiling points
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 #43345)
Chemistry
NECO SSCE 2001
Atomic Structure and Periodic Table
The Atomic theory model which explains that electrons in an atom revolve round quantized energy levels is attributed to
A
Becquerel.
B
Bohr.
C
de Broglie.
D
Rutherford.
E
Thompson.
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 #43346)
Chemistry
NECO SSCE 2001
Matter & Separation Techniques
Which compound will have the lowest boiling point?
A
CH3OH
B
CH3COOH
C
CH3CHOH
D
C4H10
E
(CH3)3CH
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 #43347)
Chemistry
NECO SSCE 2001
Stoichiometry & Mole Concept
Solution
The molar mass of a compound X is 56. its empirical formula is CH2. X is
A
butene.
B
butyne.
C
ethene.
D
propene.
E
propyne
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
\((CH_{2})x = 56\)
\((12 + 2)x = 56\)
\(14x = 56\)
\(x = \frac{56}{14}\)
\(x = 4\)
Hence, the empirical formula is \((CH_{2}) \times 4\)
= \(C_{4}H_{8}\)
Source: Myschool Past Questions Archive (Record #43348)