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Physics
UTME / JAMB 2003
Atomic, Quantum, Nuclear Physics & Electronics
Solution
If the uncertainty in the measurement of the position of a particle is 5.0 x 10-10m, the uncertainty in the momentum of the particle is
A
1.32 x 10-44Ns
B
3.30 x 10-44Ns
C
1.32 x 10-24Ns
D
3.30 x 10-24Ns
medium Difficulty
Verified Correct Answer: Option C
Physical Principles & Numerical Solution
From the uncertainty principle the product of the position and momentum of a sub-atomic particle is equal or greater than planck's constant.
i.e \( \Delta x. \Delta p \geq h.\)
\(\text{Thus} 5 \times 10^{-10} \times \Delta p = 6.6 \times 10^{-34}\)
\(\Delta p = \frac{6.6 \times 10^{-34}}{5 \times 10^{-10}} = 1.32 \times 10^{-24}Ns\)
\(\text{Therefore Uncertainty in the momentum } = 1.32 \times 10^{-24}Ns \)
Source: Myschool Past Questions Archive (Record #41458)
Physics
UTME / JAMB 2003
Atomic, Quantum, Nuclear Physics & Electronics
Solution
In a fission process, the decrease in mass is 0.01%. How much energy could be obtained from the fission of 0.1g of the material
A
\( 9.0 \times 10^{9}J \)
B
\( 9.0 \times 10^{10}J \)
C
\( 6.3 \times 10^{11}J \)
D
\( 9.0 \times 10^{11}J \)
medium Difficulty
Verified Correct Answer: Option A
Physical Principles & Numerical Solution
In general, the energy released during nuclear fission is given by Einstein's mass-energy equation, given by
\( E = \Delta MC^2 \)
Where \( \Delta m\) is the mass defect, and C is the speed of light.
Therefore
\( \Delta m = 0.01% \text{of} 1.0g = \frac{0.01}{100}\times 1.0g \)
= 1.0 \(\times 10^{-4} \)
= 1.0 \(\times 10^{-7}kg\)
\(\text{Energy Released } = \Delta MC^2 \)
= 1.0 \(\times 10^{-7} \times (3.0 \times 10^8)^2\)
= 1.0 \(\times 10^{-7} \times 9.0 \times 10^{16} \)
= 9.0 \(\times 10^9 J \)
Source: Myschool Past Questions Archive (Record #41459)
Chemistry
UTME / JAMB 2003
Kinetic Theory of Matter & Gas Laws
Solution
What volume of oxygen is produced from the decomposition of 2 mole of KCIO3 at s.t.p?
[Molar volume of a gas at s.t.p = 22.4 dm3]
A
22.4 dm3
B
33.6 dm3
C
44.8 dm3
D
67.2 dm3
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
2KClO3 → 2KCl + 3O2
3 moles of oxygen is produced
1 moles of oxygen is 22.4 dm3
3 moles of oxygen is 67.2 dm3
Source: Myschool Past Questions Archive (Record #2226)
Chemistry
UTME / JAMB 2003
Nature of Matter & Separation Techniques
Solution
Which of the following is physical change?
A
Burning kerosene
B
Freezing ice cream
C
Exposing white phosphorus
D
Dissolving calcium in water
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Option A, C and D are irreversible but option B is reversible because the frozen ice cream can undergo melting and turn into liquid and vice versa, hence no new substance is formed.
Source: Myschool Past Questions Archive (Record #2227)
Chemistry
UTME / JAMB 2003
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
What is the percentage by mass of oxygen in Al2(SO4)3. 2H2O?
[Al = 27, S = 32, H = 1, O = 16]
A
14.29%
B
25.39%
C
50.79%
D
59.25%
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Al2(SO4)3. 2H2O
2 * 27 + 3*32 + 14 * 16 + 4 * 1 =
54 + 96 + 224 + 4 = 378
% O2 = (224/378) * (100/1) = 59.25%
Source: Myschool Past Questions Archive (Record #2231)
Chemistry
UTME / JAMB 2003
Nature of Matter & Separation Techniques
Solution
The filter in the cigarette reduces the nicotine content by
A
Burning
B
Adsorption
C
Evaporation
D
Absorption
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
The nicotine content is a solute carried by the smoke (mobile phase) and it is removed by the filter (stationary phase) by adsorption. Adsorption is the process by which a solid holds molecules of a gas or liquid or solute as a thin film.
Source: Myschool Past Questions Archive (Record #2233)
Chemistry
UTME / JAMB 2003
Stoichiometry, Mole Concept & Volumetric Analysis
Solution
3Cu + pHNO3 →3Cu(NO)2 + 4H2 O + xNO
In the equation above, the values of p and x respectively are
A
1 and 3
B
2 and 3
C
6 and 2
D
8 and 2
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The examiner wishes to test your knowledge on balancing of chemical equation.
To balance, calculate the total number of H atom on the RHS, and balance with one on the LHS, you'll discover it's 8. That would be the value of P.
Next will be the number of moles of NO on the RHS, you'll discover it is 2.
Thus, P = 8 while X = 2 .
Source: Myschool Past Questions Archive (Record #2234)
Chemistry
UTME / JAMB 2003
Atomic Structure, Orbitals & Nuclear Chemistry
Solution
Neutral atoms of neon with atomic number 10 have the same number of electron as
A
O2+
B
Ca2+
C
K+
D
Mg2+
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Neutral atom of Ne has 10 electrons. Similarly, Mg\(^{2+}\) has 12 protons(atomic number) and 10 electrons because Mg\(^{2+}\) will donate or give out 2 electrons from the 12 and become reduced to 10 electrons. On the other hand, O\(^{2+}\), Ca\(^{2+}\), and K\(^+\) all have 6, 18 and 18 electrons respectively.
Source: Myschool Past Questions Archive (Record #2235)
Chemistry
UTME / JAMB 2003
Periodic Table & Periodicity
Solution
The noble gases owe their inactivity to
A
Octet configuration
B
Cyclic shape
C
Hexagonal shape
D
Obtuse configuration
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
Noble gases, also known as inert gases, are chemically inert because their outer electron shells are completely filled with electrons. i.e their octet configuration
Source: Myschool Past Questions Archive (Record #2236)
Chemistry
UTME / JAMB 2003
Kinetic Theory of Matter & Gas Laws
Solution
According to the kinetic theory, an increase in temperature causes the kinetic energy of particles to
A
Decrease
B
Increase
C
Remain constant
D
Be zero
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Kinetic energy is a measure of the motion of particles, and when temperature increases, the particles absorb energy and move faster. This results in an increase in the kinetic energy of the particles.
Source: Myschool Past Questions Archive (Record #2237)
Chemistry
UTME / JAMB 2003
Metals, Transition Elements & Extraction
Solution
I. H = 1S\(^1\) II. N = 1S\(^2\) 2S\(^2\)2P\(^3\) III. O = 1S\(^2\) 2S\(^2\) 2P\(^4\) IV. Zn = 1S\(^2\) 2S\(^2\) 2P\(^6\) 3S\(^2\) 3P\(^6\) 4S\(^2\) 3d\(^{10}\)
From the above, which of the following pairs is like to be paramagnetic?
A
I and II
B
I and III
C
I and IV
D
III and IV
medium Difficulty
Verified Correct Answer: Option B
Chemical Principles & Mechanism
Paramagnetic materials are materials that tend to get weakly magnetized in the direction of the magnetizing field when placed in a magnetic field. Paramagnetic elements are elements that have at least one unpaired electron and are slightly attracted to magnetic fields.
Examples: Copper, gold, antimony, bismuth, silver, lead, silicon, mercury, water, Oxygen, hydrogen, nitrogen, etc
By elimination method, options C and D are eliminated because of Zinc, which is diamagnetic as it has no unpaired electron. Between options A and B, both have H present with difference of Oxygen and Nitrogen, with Oxygen being more paramagnetic than Nitrogen because molecular oxygen (O2) is paramagnetic and is attracted to the magnet. In contrast, molecular nitrogen (N2) has no unpaired electrons and is diamagnetic; it is unaffected by the magnet.
Source: Myschool Past Questions Archive (Record #2238)
Chemistry
UTME / JAMB 2003
Kinetic Theory of Matter & Gas Laws
Solution
A gas exerts pressure on its container because
A
some of its molecules are moving faster than others
B
of the collision of the molecules with each other
C
of the mass of the molecules of gas
D
the molecules of a gas collide with the walls of the container
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
A gas exerts pressure on the walls of the container as the particles of gas move randomly in all directions at high speed. As a result, the particles hit each other and also hit the walls of the container with force. However, gases exert pressure on their containers because the constant, random motion of gas molecules causes them to collide with the container walls, transferring momentum and resulting in a force, which is pressure.
Source: Myschool Past Questions Archive (Record #2251)
Chemistry
UTME / JAMB 2003
Electrolysis & Electrochemical Cells
Solution
When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes
A
negatively charged
B
positvely charged
C
neutral
D
bipolar
medium Difficulty
Verified Correct Answer: Option A
Chemical Principles & Mechanism
When cathode rays are deflected onto the electrode of an electrometer, the instrument becomes negatively charged. Cathode rays are streams of fast-moving electrons that are negatively charged. When they are deflected towards a positive electrode, it demonstrates that they are negatively charged. This is because opposite charges attract each other.
Source: Myschool Past Questions Archive (Record #2252)
Chemistry
UTME / JAMB 2003
Chemical Bonding & Intermolecular Forces
Solution
The weakest attractive force that can be observed between two molecules is
A
ionic
B
covalent
C
coordinate covalent
D
van der Waals
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
The weakest attractive force between two molecules is the London dispersion force, also known as an induced dipole-induced dipole attraction. London dispersion forces are a type of van der Waal force, which are weak intermolecular forces that determine the physical and chemical properties of substances
Source: Myschool Past Questions Archive (Record #2253)
Chemistry
UTME / JAMB 2003
Atomic Structure, Orbitals & Nuclear Chemistry
Solution
Which of the following ions is acidic?
A
K+
B
KNO3-
C
S2-
D
H3O+
medium Difficulty
Verified Correct Answer: Option D
Chemical Principles & Mechanism
Acids are substances which produces hydrogen ions (or protons) as the only positive ion when dissolved in water.
\(H_{3}O^{+} \to 2H^{+} + OH^{-}\)
Source: Myschool Past Questions Archive (Record #2256)