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Chemistry
UTME / JAMB 2024
Matter & Separation Techniques
Diagram
Solution
The IUPAC nomenclature of the compound above is
Attached Figure / Diagram
A
propan-1-ol
B
butan-1-ol
C
2-methyl propan-1-ol
D
2-methyl propan-2-ol
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The IUPAC nomenclature of the compound above is 2-methylpropan-2-ol.
Source: Myschool Past Questions Archive (Record #70299)
Chemistry
UTME / JAMB 2024
Acids, Bases, and Salts
Solution
What is formed when metal reacts with acid to liberate gas?
A
Salt
B
Base
C
Acid
D
Liquid
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
When a metal reacts with an acid, hydrogen gas and a metal salt are formed.
Metal + acid → salt + hydrogen
2Na + 2HCl → 2NaCl + H\(_2\)
Source: Myschool Past Questions Archive (Record #70301)
Chemistry
UTME / JAMB 2024
Acids, Bases, and Salts
Solution
Concentrated sodium chloride solution is electrolyzed using mercury cathode and graphite anode. The products at the anode and the cathode respectively are
A
hydrogen and chlorine
B
chlorine and hydrogen
C
chlorine and sodium
D
sodium and chlorine
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
1:Identify the components involved in the electrolysis: The electrolysis involves a concentrated sodium chloride (NaCl) solution, a mercury cathode, and a graphite anode.
2: Determine the reactions at the electrodes: At the anode (oxidation), chlorine gas is produced because the potential for chlorine evolution is lower than that of oxygen evolution in a concentrated NaCl solution. The reaction is 2Cl^- → Cl2 + 2e^-.
3: Determine the reaction at the cathode: At the mercury cathode (reduction), sodium is produced and forms an amalgam with mercury because the potential for sodium reduction is lower than that of hydrogen evolution due to the high overpotential of hydrogen on mercury. The reaction is Na^+ + e^- → Na.
4: Identify the products: The products are chlorine gas (Cl2) at the anode and sodium (which forms an amalgam with mercury) at the cathode.
This implies Chlorine is produced at the anode and sodium at the cathode.
The correct answer is C.
Source: Myschool Past Questions Archive (Record #70304)
Chemistry
UTME / JAMB 2024
Atomic Structure and Periodic Table
Solution
When n = 3, the quantum number of an element is
A
3
B
9
C
18
D
21
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Quantum numbers are a set of numbers that describe the position and energy of an electron in an atom.
When the quantum number is equal to 3, the possible values for the azimuthal quantum number are 0, 1, and 2:
l=0, The resulting subshell is an "s" subshell.
l =1, The resulting subshell is a "p" subshell.
l =2: The resulting subshell is a "d" subshell.
The three possible sub-shells when n=3 are 3s, 3p, and 3d.
Source: Myschool Past Questions Archive (Record #70310)
Chemistry
UTME / JAMB 2024
Acids, Bases, and Salts
Solution
The salt formed when strong acid reacts with strong base is
A
normal
B
double
C
complex
D
basic
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
The type of salt that is formed when a strong acid reacts a strong base is a neutral salt which is also a normal salt. This is because the strong acid is completely neutralized by the base that is strong in nature. E.g sodium chloride, NaCl.
Source: Myschool Past Questions Archive (Record #70311)
Chemistry
UTME / JAMB 2024
Atomic Structure and Periodic Table
Solution
The shape of the molecule of Carbon(IV) oxide is
A
tetrahedral
B
pyramidal
C
plannar
D
linear
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
CO\(_2\) is made up of one carbon atom and two oxygen atoms. The molecule's linear shape is due to the arrangement of its atoms and the absence of lone pairs on the central carbon atom.
The molecule's linear shape is also due to the cancellation of the charges of the dipole when the molecule is arranged symmetrically. The two C=O bonds are polar, but the rest of the molecule is nonpolar.
Source: Myschool Past Questions Archive (Record #70312)
Chemistry
UTME / JAMB 2024
Atomic Structure and Periodic Table
Solution
\(^{238}_{92}\)U + \(^1_0\)n → \(^{239}_{92}\)U
The process above produces
A
atomic mutation
B
a radioactive isotope
C
other neutrons
D
radiations
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Atomic mutations, or radiation-induced mutations, are changes in DNA that occur when ionizing radiation damages DNA in cells.
Radioactive isotope, any of the species of the same chemical element that have different masses and unstable nuclei that emit radiation.
Radiation is the release of energy from a source in the form of particles or electromagnetic waves that travel through a medium and are absorbed by matter
Source: Myschool Past Questions Archive (Record #70317)
Chemistry
UTME / JAMB 2024
Stoichiometry & Mole Concept
Solution
Calculate the mass of Magnesium that will be liberated from its salt by the same quantity of electricity that liberated 16.0 g of Silver.
[Mg = 24.0, Ag = 108 ]
A
3.65 g
B
3.56 g
C
1.87 g
D
1.78 g
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Firstly, Ag\(^+\) + e\(^-\) → Ag
1 mole = 1 F = 96,500C x 1 e\(^-\)
⇒ If 96,500C liberates 108g of Ag
x will liberate 16g of Ag
x = \(\frac{96,500 x 16}{108}\) = 14,296.30 C
i.e The quantity of electricity that would liberate 16g of Ag which is also the same quantity that will liberate X of Mg = 14,296.30 C
Thus, Mg\(^{2+}\) + 2e\(^-\) → Mg
If 2e\(^-\) X 96,500C liberates 24g of Mg
14,296.30C will liberate Xg of Mg
By simple proportion, X = \(\frac{14,296.30 x 24}{193,000}\)
= 1.78g
Source: Myschool Past Questions Archive (Record #70375)
Chemistry
UTME / JAMB 2024
Matter & Separation Techniques
Solution
Which of the following is an air pollutant?
A
O\(_2\)
B
CO
C
H\(_2\)O\((_g\))
D
O\(_3\)
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Carbon monoxide (CO) is an air pollutant. It's a common air pollutant that's also known as a deadly household gas.
Source: Myschool Past Questions Archive (Record #70376)
Chemistry
UTME / JAMB 2024
Stoichiometry & Mole Concept
Solution
The volume in cm\(^3\) of a 0.12 moldm\(^{-3}\) HCl required to completely neutralize a 20cm\(^3\) of 0.20 moldm\(^{-3}\) of NaOH is
A
12.00
B
0.0012
C
33.33
D
2.40
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
First, write a balanced equation and ensure the stoichiometry is in order:
HCl + NaOH → NaCl + H\(_2\)O
Following the reaction above, the mole ratio is 1 : 1
Given:
Concentration of Acid, C\(_A\) = 0.12moldm\(^{-3}\), Volume of Acid, V\(_A\) = ?
Concentration of Base, C\(_B\) = 0.20 moldm\(^{-3}\) Volume of Base, V\(_B\) = 20cm\(^3\)
Using the relation, C\(_A\)V\(_A\) = C\(_B\)V\(_B\)
V\(_A\) = \(\frac{C_BV_B}{C_A}\)
= \(\frac{0.20 \times 20}{0.12}\)
= 33.33cm\(^3\)
Source: Myschool Past Questions Archive (Record #70377)
Chemistry
UTME / JAMB 2024
Matter & Separation Techniques
Solution
Fog is a colloid in which
A
liquid particles is dispersed in a gas medium
B
gas particles dispersed in a liquid medium
C
solid particles dispersed in a gas medium
D
gas particles dispersed in a solid medium
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Fog is a thick cloud of tiny water droplets or ice crystals that forms near the ground, making it difficult to see. Fog is a colloidal solution, which is a mixture where one substance is evenly dispersed in another. In fog, the dispersed phase is liquid, and the dispersion medium is gas. Fog is also known as a liquid aerosol.
- Liquid particle dispersed in gas medium is Fog
- Gas particles dispersed in liquid is Foam or lather
- Solid particles dispersed in gas is smoke
- gas particles dispersed in solid is solid sols
- Liquid dispersed in liquid is emulsion
Source: Myschool Past Questions Archive (Record #70378)
Chemistry
UTME / JAMB 2024
Atomic Structure and Periodic Table
Solution
Determine the empirical formula of an oxide of sulphur containing 60% of oxygen
[S = 32, O = 16 ]
A
SO\(_3\)
B
SO\(_2\)
C
SO\(_4\)
D
SO
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Oxide of Sulphur means the compound formed is bonding between Sulphur and Oxygen.
Also, if the compound contains 60% Oxygen, then it must contain 40% Sulphur
Elements S O
%by mass of atoms 40 60
Divide by their masses \(\frac{40}{32}\) \(\frac{60}{16}\)
1.25 3.75
Divide through by smaller value \(\frac{1.25}{1.25}\) \(\frac{3.75}{1.25}\)
1 : 3
Empirical formula SO\(_3\)
Source: Myschool Past Questions Archive (Record #70379)
Chemistry
UTME / JAMB 2024
Atomic Structure and Periodic Table
Solution
The scientist that performed the experiment on discharged tubes that led to the discovery of the cathode rays as a sub-atomic particle is
A
J.J Thomson
B
Robert Millikan
C
Ernest Rutherford
D
Niels Bohr
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
J.J. Thomson performed the cathode ray tube (CRT) experiment that led to the discovery of the electron and cathode rays as subatomic particles.
Robert Millikan succeeded in precisely determining the magnitude of the electron's charge.Millikan's discovery that electron charge can be quantified led to an accepted value for e\(^-\), which is now a fundamental scientific constant.
Ernest Rutherford discovered alpha and beta rays, set forth the laws of radioactive decay, and identified alpha particles as helium nuclei.
Bohr's model of the atom describes how electrons orbit a nucleus in defined energy levels. Electrons can move between orbits by absorbing or emitting energy.
Source: Myschool Past Questions Archive (Record #70380)
Chemistry
UTME / JAMB 2024
Acids, Bases, and Salts
Solution
In the treatment of water for municipal supply, chlorine is used to
A
prevent tooth decay
B
prevent goitre
C
kill germs
D
remove colour or odour
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
Chlorine kills or inactivates harmful microorganisms that can cause illnesses like cholera, hepatitis, typhoid, and giardiasis. It helps in disinfecting the potable water.
Source: Myschool Past Questions Archive (Record #70381)
Chemistry
UTME / JAMB 2024
Matter & Separation Techniques
Solution
The combustion of candle under limited supply of air forms
A
water and CO\(_2\)
B
water and CO
C
soot and CO
D
soot and CO\(_2\)
medium Difficulty
Verified Correct Answer: Option C
Chemical Principles & Mechanism
When a candle burns in a limited supply of air, it undergoes incomplete combustion, producing carbon (soot) and carbon monoxide (CO) instead of carbon dioxide and water.
Source: Myschool Past Questions Archive (Record #70382)