General Chemistry I — 2026-test Past Questions

University of Ilorin CHM101: 73 questions.

Topics: Elementary thermochemistry, Chemical kinetics, Redox reactions and introduction to electrochemistry, Periodicity and building up of the periodic table, Properties of gases, Modern electronic theory of atoms, Atoms, elements, molecules, Electronic configuration, Radioactivity, Kinetic theory of matter, Chemical bonding and intermolecular forces

1. A zero-order reaction has the same unit for its rate constant as the?
   1. Rate
   2. Time
   3. Reactant concentration
   4. None of the above
2. Who performed the oil drop experiment?
   1. J. J. Thomson
   2. Robert Millikan
   3. Ernest Rutherford
   4. Niels Bohr
3. Who discovered the proton?
   1. J.J. Thomson
   2. Ernest Rutherford
   3. James Chadwick
   4. John Dalton
4. Which postulate of Dalton's atomic theory was later proven to be incorrect?
   1. Atoms of different elements possess different chemical properties.
   2. Atoms cannot be created or destroyed during a chemical reaction.
   3. Atoms of a given element are identical in mass and properties.
   4. Compounds are formed by the combination of two or more different kinds of atoms.
5. A chemical system consisting of two immiscible liquids is classified as a?
   1. One-phase system
   2. Two-phase system
   3. Three-phase system
   4. Homogeneous mixture
6. A zero-order reaction has a rate constant of 0.003 mol L⁻¹ s⁻¹. How long will it take for the concentration of reactant A to fall from 0.1 M to 0.075 M?
   1. 33.33 seconds
   2. 12.50 seconds
   3. 8.33 seconds
   4. 25.00 seconds
7. In a heterogeneous equilibrium, which of the following species are omitted from the Kc expression?
   1. Gases
   2. Pure solids and liquids
   3. Aqueous solutions
   4. Dissolved ions
8. Given the following thermochemical equations: (i) 2H₂(g) + O₂(g) → 2H₂O(l) ΔH = −571.6 kJ; (ii) 2H₂(g) + O₂(g) → 2H₂O(g) ΔH = −483.6 kJ. Calculate the enthalpy of vaporization (heat required to vaporize 1 mole) of water.
   1. −44.0 kJ
   2. −88.0 kJ
   3. +88.0 kJ
   4. +44.0 kJ
9. Which scientist is credited with the discovery of the electron in 1897?
   1. Ernest Rutherford
   2. James Chadwick
   3. J.J. Thomson
   4. Niels Bohr
10. What is the electrical charge associated with a neutron?
    1. Positive
    2. Negative
    3. No charge
    4. Bipolar
11. Which of the following describes a Daniell cell?
    1. Zn/Zn²⁺ and Cu/Cu²⁺ electrodes
    2. Pb/Pb²⁺ and Ag/Ag⁺ electrodes
    3. Fe/Fe²⁺ and Ni/Ni²⁺ electrodes
    4. Mg/Mg²⁺ and Al/Al³⁺ electrodes
12. Which type of electrochemical cell operates by using an external current to drive a non-spontaneous reaction?
    1. Galvanic cell
    2. Electrolytic cell
    3. Voltaic cell
    4. Fuel cell
13. Which of the following is a characteristic of a zero-order reaction?
    1. The rate is proportional to the square of concentration
    2. The half-life increases as initial concentration decreases
    3. The rate of reaction is independent of reactant concentration
    4. The concentration of reactants remains constant over time
14. What is the unit of the rate constant for a zero-order reaction?
    1. s⁻¹
    2. L² mol⁻² s⁻¹
    3. L mol⁻¹ s⁻¹
    4. mol L⁻¹ s⁻¹
15. A redox reaction has a standard electrode potential (E°) of −1.00 V. What type of reaction is it?
    1. Spontaneous
    2. Adiabatic
    3. Equilibrium
    4. Non-spontaneous
16. What does the rate of a chemical reaction depend on?
    1. Catalyst only
    2. Temperature only
    3. Concentration of reactants
    4. Volume of container
17. A metal of mass 500 g is heated and absorbs 4200 J of heat. If its temperature rises by 20°C, what is its specific heat capacity?
    1. 420 J/kg°C
    2. 4200 J/kg°C
    3. 210 J/kg°C
    4. 1050 J/kg°C
18. According to the kinetic theory, gases exert pressure because?
    1. Gas particles have mass
    2. Gas particles occupy space
    3. Gas particles collide with container walls
    4. Gas particles are weightless
19. Which of the following is not classified as a reference electrode?
    1. Standard Hydrogen Electrode
    2. Silver-Silver Chloride Electrode
    3. Membrane Electrode
    4. Saturated Calomel Electrode
20. How many Gray (Gy) are equivalent to 1 rad?
    1. 100 Gy
    2. 10 Gy
    3. 0.01 Gy
    4. 0.1 Gy
21. A radiation dose of 1000 rem is equivalent to how many Sieverts (Sv)?
    1. 1 Sv
    2. 100 Sv
    3. 10 Sv
    4. 0.1 Sv
22. Consider the chemical reaction: 2A + B → C. If the reaction is determined to be zero order overall, what is the correct rate law expression?
    1. Rate = k[A]²[B]
    2. Rate = k[A][B]
    3. Rate = k
    4. Rate = k[C]
23. What are the standard quality factors (Q) for alpha and beta radiation, respectively?
    1. Alpha = 1, Beta = 20
    2. Alpha = 5, Beta = 5
    3. Alpha = 1, Beta = 1
    4. Alpha = 20, Beta = 1
24. For a given substance, which of the following phase changes generally involves the largest change in enthalpy?
    1. Heat of fusion
    2. Heat of vaporization
    3. Heat of condensation
    4. Heat of sublimation
25. Which of the following terms is used to describe the atomic model proposed by Ernest Rutherford?
    1. Plum pudding model
    2. Planetary model
    3. Billiard ball model
    4. Electron cloud model
26. A molecule of a compound contains?
    1. Only one type of atom
    2. At least two different types of atoms
    3. Only metallic atoms
    4. At least three different types of atoms
27. When all reactants and products in a reversible reaction are in the same phase, the equilibrium is known as?
    1. Heterogeneous equilibrium
    2. Static equilibrium
    3. Phase-shifting equilibrium
    4. Homogeneous equilibrium
28. A dynamic equilibrium is often likened to a person walking on an escalator or moving in an elevator because?
    1. The system has stopped all motion and energy transfer
    2. The concentration of products has become zero
    3. The rate of the forward process equals the rate of the reverse process
    4. The volume of the container is constantly changing
29. What is the molar heat capacity of 100 g of water if it absorbs 836 J of heat and the temperature changes from 298 K to 300 K?
    1. 75.2 J/mol K
    2. 41.8 J/mol K
    3. 4.18 J/mol K
    4. 150.4 J/mol K
30. The elements in group 17 are called?
    1. Halogens
    2. Noble gases
    3. Alkalis
    4. Alkaline earth metals
31. In an exothermic reaction, the products have ____ and the enthalpy change (ΔH) is ____?
    1. Higher potential energy and positive
    2. Lower potential energy and positive
    3. Higher potential energy and negative
    4. Lower potential energy and negative
32. When the number of moles of gas and the temperature are kept constant, the pressure can be increased by?
    1. Decreasing the volume of the container
    2. Increasing the volume of the container
    3. Adding more inert gas at constant volume
    4. Removing some of the gas from the container
33. Which of the following uses electricity to drive a non-spontaneous chemical reaction?
    1. Electrochemical cell
    2. Electrolytic cell
    3. Voltaic cell
    4. Fuel cell
34. Which of the following processes is not endothermic?
    1. Water boiling
    2. Ice melting
    3. Water evaporation
    4. Condensation of water
35. Which of the following subshells is progressively filled in the lanthanide series?
    1. 4d
    2. 4f
    3. 5d
    4. 5f
36. When you sit on a filled balloon and it bursts, which law does it obey?
    1. Charles' law
    2. Law of pressure gradient
    3. Boyle's law
    4. None of the above
37. Graham's Law of Diffusion states that the rate of diffusion of a gas is inversely proportional to the?
    1. Molar mass
    2. Square of the molar mass
    3. Cube root of the molar mass
    4. Square root of the molar mass
38. Which of the following processes has the highest positive enthalpy change?
    1. Enthalpy of fusion
    2. Enthalpy of vaporization
    3. Enthalpy of sublimation
    4. Enthalpy of condensation
39. 4Fe(s) + 3O₂(g) → 2Fe₂O₃(s). If the enthalpy of formation (ΔHf) of Fe₂O₃ is −822 kJ/mol, what is the enthalpy of the reaction shown above?
    1. −411 kJ
    2. +411 kJ
    3. −1644 kJ
    4. +1644 kJ
40. A reaction with an initial concentration of 4 M decreases to 2 M in 1 hour, and from 2 M to 1 M in 0.5 hours. What is the order of the reaction?
    1. Zero order
    2. First order
    3. Second order
    4. Third order
41. What is the volume of one mole of a gas at 300 K and 10⁵ Pa if it was initially at STP?
    1. 0.024 dm³
    2. 24.94 dm³
    3. 0.24 dm³
    4. 249.0 dm³
42. If a container contains 8.0 g of oxygen and 14.0 g of nitrogen, find the partial pressure of oxygen if the total pressure is 750 mmHg.
    1. 500 mmHg
    2. 750 mmHg
    3. 1000 mmHg
    4. 250 mmHg
43. Which term describes the energy required to remove an electron from an isolated gaseous atom to form a positive ion?
    1. Electron affinity
    2. Lattice energy
    3. Ionization energy
    4. Electronegativity
44. The heat exchanged by a system at constant volume is equal to its change in?
    1. Enthalpy
    2. Work done
    3. Internal energy
    4. Entropy
45. If the enthalpy change for the reaction H₂ + Cl₂ → 2HCl is −185.5 kJ, what is the enthalpy change for the reaction 2H₂ + 2Cl₂ → 4HCl?
    1. −92.75 kJ
    2. −185.5 kJ
    3. +371 kJ
    4. −371 kJ
46. Which of the following statements is true regarding a thermochemical reaction and its reverse?
    1. The backward reaction has a different numerical value for enthalpy than the forward reaction.
    2. Both the forward and backward reactions are always exothermic.
    3. The forward and backward reactions have the same numerical value but opposite signs.
    4. The backward reaction always requires double the energy of the forward reaction.
47. Atoms which have the same number of protons are?
    1. Isobars
    2. Isotones
    3. Isotopes
    4. None of these
48. A gas occupies 12.0 L at 2.0 atm. If the volume is decreased to 4.0 L at constant temperature, the new pressure will be?
    1. 1.0 atm
    2. 3.0 atm
    3. 6.0 atm
    4. 8.0 atm
49. Which gas will diffuse at the slowest rate at a given temperature?
    1. CH₄
    2. NH₃
    3. CO₂
    4. H₂
50. Which principle states that no two electrons can have the same set of quantum numbers?
    1. Aufbau's principle
    2. Pauli's exclusion principle
    3. Hund's rule
    4. Octet rule
51. What are the numbers of electrons in the s, p, d, and f orbitals (subshells)?
    1. 2, 6, 10, 14
    2. 1, 4, 9, 16
    3. 2, 8, 18, 32
    4. 4, 12, 18, 24
52. The electron affinity of an atom generally ______ in magnitude across a period?
    1. Decreases
    2. Increases
    3. Remains constant
    4. Oscillates
53. Which of the following has the largest size?
    1. Mg
    2. Na
    3. Al
    4. Si
54. The heat flow in a system at constant temperature and pressure is?
    1. Standard entropy
    2. Enthalpy
    3. Internal energy
    4. Work done
55. Which of the following has the smallest radius?
    1. Li⁺
    2. Mg²⁺
    3. Al³⁺
    4. Na⁺
56. Which of the following pairs are isotones?
    1. ¹⁴C and ¹⁴N
    2. ¹⁵N and ¹⁶O
    3. ⁴⁰Ca and ⁴⁰Ar
    4. ³⁹K and ⁴¹K
57. The second electron affinity of an atom is always?
    1. Negative
    2. Positive
    3. Zero
    4. Infinity
58. Which of these is not true about gas?
    1. Gas has a definite shape.
    2. Gas has no definite shape.
    3. Gas has no definite volume.
    4. Gas fills its container completely.
59. Which of the following describes the process in which heat is released to the surroundings?
    1. Exothermic and positive
    2. Endothermic and neutral
    3. Endothermic and positive
    4. Exothermic and negative
60. The purple color of iodine is due to?
    1. Gaseous iodine molecules
    2. Solid iodine
    3. Aqueous iodine solution
    4. Iodide ions
61. For a zero-order reaction, the time for complete disappearance of the reactant (t₁₀₀) is given by?
    1. [A]₀/k
    2. 2[A]₀/k
    3. [A]₀/2k
    4. k/[A]₀
62. Which of the following best represents the energy released when 1 mole of an ionic solid is formed from its gaseous ions?
    1. Ionization energy
    2. Lattice energy
    3. Electron affinity of the non-metal
    4. Bond dissociation energy
63. For the cell K | KI || Cu²⁺ | Cu, which of the following denotes the anode?
    1. K
    2. Cu
    3. KI
    4. Cu²⁺
64. Which of the following is the most common reference electrode?
    1. Silver-silver chloride electrode
    2. Membrane electrode
    3. Calomel electrode
    4. Normal hydrogen electrode
65. Faraday's First Law of Electrolysis can be represented by which of the following?
    1. m ∝ Q
    2. m = Q/nF
    3. m = C × V
    4. m = I² × R × t
66. Oxidation takes place at the?
    1. Electrolytic cell
    2. Cathode
    3. Electrochemical cell
    4. Anode
67. Which of the following ions has the smallest radius?
    1. O²⁻
    2. F⁻
    3. Mg²⁺
    4. Na⁺
68. For a galvanic cell, E°cell = −1.10 V. Which of the following is true?
    1. It is spontaneous
    2. ΔG is positive
    3. ΔG is negative
    4. It is at equilibrium
69. A low value of the equilibrium constant (Kc) indicates that?
    1. More products have been formed
    2. The reaction is at equilibrium
    3. There are more reactants than products
    4. The reaction is homogeneous
70. The enthalpy change for the reaction 2NO₂ → N₂ + O₂ is −114 kJ. What is the enthalpy change for the reaction N₂ + O₂ → 2NO₂?
    1. +114 kJ
    2. −57 kJ
    3. +57 kJ
    4. −114 kJ
71. Which of the following reactions will occur in a second or at a faster rate?
    1. A reaction that involves a gaseous reactant
    2. A catalyzed reaction
    3. A reaction with a high activation energy
    4. A reaction occurring at low temperature
72. In a galvanic cell, electrons flow from the ____ where ____ occurs?
    1. anode, reduction
    2. cathode, oxidation
    3. anode, oxidation
    4. cathode, reduction
73. A system where energy and matter are conserved (no exchange with the surroundings) is?
    1. Open system
    2. Closed system
    3. Isolated system
    4. Heterogeneous system

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