Legetafo Innovative Boarding Academy
TIME ALLOWED: 2:30 HOURS
Directions: -In this examination, there are a total of 80 multiple choice
questions. Each of the questions is followed by four possible alternatives.
Choose the best answer and blacken only the letter of your choice on the
separate answer sheet provided. You will be allowed to work for 2:30 hours.
Any form of cheating or an attempt to cheat in the examination hall will result
in an automatic dismissal from the examination hall and cancellation of your
score(s).
1. Consider the hypothetical reaction below. In which of the following will the effect of
concentration and temperature simultaneously cause an increase in the rate at which
products are formed?2A(g)+B(g)⇄3C(g)+Heat
A. Decrease[B] and Decrease temperature
B. Increase[B] and decrease temperature
C. Increase [B]and decrease temperature
D. Liquefy A and decrease temperature
2. The hydrogen used in the Haber process is made by the following reactions.
CH4(g)+H2O(g)⇄CO(g)+3H2(g),∆H0=205kJ. Which of the following sets of conditions will
favor the formation of H2?
A. Low pressure and High temperature
B. Low pressure and low temperature
C. High pressure and low temperature
D. High pressure and high temperature
3. For a reaction to shift towards the reactant direction which of the following condition holds
TRUE?
A. Qc<Kc B. Qc>Kc C. Qc=Kc=O D. Qc=Kc
4. Which of the following solutions would have a pH value greater than 7?
A. [OH–] = 1 × 10–2 M C. [OH¯] = 1 × 10–9 M
B. 0.0001 M HCl D. [H3O+] = 1 × 10–2 M
5. Which one of the following is a diprotic acid?
A. Hydrochloric acid B. Phosphoric acid C. Sulfuric acid D. Acetic acid
6. In the Lewis formula for PCl3, phosphorous is surrounded by ________ bonding and
nonbonding electron pairs respectively.
A. 9, 3 B. 1, 3 C. 3, 1 D. 3, 9
7. Gas X diffuses twice as fast as gas Y. Gas Y has a molecular weight of 60g/mol. What is the
molar mass of gas X?
A. 12g/mol B. 15g /mol C. 30g/mol D. 90g/mol
8. Vaporization of solids without melting is known as ____________.
A. Fusion B. Sublimation C. Condensation D. Boiling
9. What is the molecular formula of open chain alkane with 14 carbon atoms?
A. C14H12 B. C14H16 C. C14H30 D. C14H28
10. Which of the following substances will release hydrogen gas when it reacts with
hydrochloric acid (HCl)?
A. Zn B. NaOH C. H2SO4 D. CaO
11. The following redox reaction shows the discharging of Lead storage battery (car battery).
Anode reaction: Pb + SO42- → PbSO4 + 2e
Cathode reaction: PbO2 + 4H+ + SO42- + 2e- → PbSO4 + 2H2O
Over all reaction: Pb + PbO2 + 4H+ + 2SO42- → 2PbSO4 + 2H2O
which one of the following statements is NOT true based on the given reaction?
A. The anode of this cell is made of lead metal |Pb|.
B. The cathode of this cell is made of lead (IV) oxide| PbO2|.
C. About 35% of H2SO4 is used as electrolyte in this cell.
D. SO42- ions are produced at both electrodes.
12. The following are characteristic of chemical industries except one. Which one is it?
A. They consume relatively small amount of energy
B. They use naturally available raw materials
C. They do not have any negative impact on environment
D. They involve chemical reactions in their production of materials.
13. The maximum number of electrons in an orbital of an atom possessing a quantum number
n= 4, l = 3, and ml = 0 is: ___________
A. 14 B. 2 C. 32 D. 8
14. For the step wise dissociation of aqueous H3PO4 which of the following is NOT a conjugate
acid- base pair?
A.H3PO4/H2PO4- B. HPO4 -2/PO4-3 C. H2PO4-/HPO4-2 D. H2PO4-1/PO4-3
15. Which of the following statements best differentiates Dalton’s atomic theory from the
modern atomic theory?
A. Dalton proposed atoms are indivisible; modern theory recognizes subatomic particles.
B. Dalton believed atoms of different elements could be identical; modern theory disagrees.
C. Dalton identified electrons; modern theory refutes their existence in orbitals.
D. Dalton's model included energy levels, which modern theory no longer uses.
16. Which experiment most directly led to the discovery that atoms have a dense, positively
charged nucleus?
A. Millikan’s oil drop experiment
B. Thomson’s cathode ray experiment
C. Rutherford’s gold foil experiment
D. Bohr’s hydrogen line spectra experiment
17, An atom has 17 protons, 18 neutrons, and 17 electrons. Which of the following is correct?
A. Atomic number = 18; Mass number = 34
B. Atomic number = 17; Mass number = 35
C. Atomic number = 35; Mass number = 17
D. Atomic number = 18; Mass number = 35
18. If an element exists as three isotopes with masses 62.93 (69.2%), 64.93 (30.8%), and 66.93
(0.0%), what is its average atomic mass?
A. 64.00 amu B. 63.55 amu C. 64.39 amu D. 62.93 amu
19. Which model first introduced the idea that electrons occupy specific energy levels?
A. Dalton model B. Thomson’s plum pudding model
C. Rutherford model D. Bohr model
20. Which electron configuration represents an atom in an excited state?
A. 1s² 2s² 2p⁶ 3s² 3p⁶ B. 1s² 2s² 2p⁶ 3s¹ 3p⁶ 3d¹
C. 1s² 2s² 2p⁶ D. 1s² 2s² 2p⁵ 3s¹
21. If element X has an electron configuration ending in 4s²3d¹⁰4p⁵, which of the following
statements is most accurate?
A. It is a noble gas.
B. It tends to lose electrons to form a +1 ion.
C. It is highly reactive and forms salts with alkali metals.
D. It has no metallic character.
22. A student places four unknown elements into two groups based on their physical properties.
Elements A and B are shiny, good conductors, and malleable. Elements C and D are brittle and
poor conductors. What is the most scientific classification for A and B versus C and D?
A. A and B are nonmetals; C and D are metals.
B. A and B are metalloids; C and D are noble gases.
C. A and B are metals; C and D are nonmetals.
D. A and B are alkali metals; C and D are halogens.
23. The atomic radius decreases across a period due to:
A. Increase in number of energy levels
B. Increase in shielding effect
C. Increase in effective nuclear charge
D. Decrease in number of protons
24. Two unknown elements, X and Y, both belong to Period 3. X forms a basic oxide, while Y
forms an acidic oxide. What is the most likely position of X and Y in the periodic table?
A. X is a nonmetal; Y is a metal
B. X is on the right; Y is on the left
C. X is in Group 1 or 2; Y is in Group 15 or 16
D. X is in Group 17; Y is in Group 1
25. A student draws a model showing lithium, sodium, and potassium in one group and fluorine,
chlorine, and bromine in another. Based on this model, which inference is most scientifically
valid?
A. All the elements behave identically.
B. Each group shares similar physical and chemical properties due to similar outer electron
configurations.
C. The elements are arranged by increasing atomic number only.
D. These elements do not show any periodicity.
26. Which statement correctly describes the bonding in ethyne (C₂H₂) according to Valence
Bond Theory?
A. Each carbon is sp² hybridized, forming one σ and two π bonds.
B. Each carbon is sp hybridized, forming one σ and two π bonds.
C. Each carbon is sp³ hybridized, forming two σ and two π bonds.
D. The triple bond is made of three σ bonds between carbon atoms
27. A scientist synthesizes a compound between magnesium and nitrogen. Which reasoning best
explains the type of bond and the resulting compound's properties?
A. A covalent bond forms because both elements are nonmetals, resulting in a low-melting-point
solid.
B. An ionic bond forms because electrons are shared equally between magnesium and nitrogen,
resulting in a brittle gas.
C. An ionic bond forms due to electron transfer from magnesium to nitrogen, resulting in a high-
melting-point crystalline solid.
D. A metallic bond forms because both elements are metals, resulting in a ductile solid.
28. A lab technician tests two unknown solids: one conducts electricity in molten form but not in
solid form; the other conducts electricity in solid form. What can be concluded about their
bonding types?
A. Both are covalent compounds.
B. The first is ionic; the second is metallic.
C. The first is metallic; the second is ionic.
D. Both are ionic compounds in different forms.
29. Which statement best explains why CHCl₃ (chloroform) is polar, even though the C–H and
C–Cl bonds are arranged symmetrically?
A. The molecule is polar because the C–Cl bonds cancel each other out.
B. The shape is nonpolar due to tetrahedral geometry.
C. The bond dipoles do not cancel because of differences in electronegativity and the
asymmetrical shape.
D. The molecule is nonpolar because the polar bonds are balanced.
30. During an experiment, a student observes a substance that dissolves in water and conducts
electricity. Which of the following steps would best support a scientific explanation for the type
of bonding present?
A. Measuring the melting point and comparing it to known metals.
B. Drawing a Lewis structure to confirm hydrogen bonding.
C. Predicting the presence of ions, testing conductivity, and comparing to known ionic
substances.
D. Assuming it is polar and making a model without further tests.
31. When 10.0 g of magnesium reacts with 10.0 g of oxygen to form magnesium oxide, the total
mass of the products is 20.0 g. This observation best supports which fundamental law?
A. Law of Definite Proportions B. Law of Multiple Proportions
C. Law of Conservation of Mass D. Law of Reciprocal Proportions
32, which of the following represents a single displacement reaction?
A. HCl + NaOH → NaCl + H₂O
B. 2H₂O₂ → 2H₂O + O₂
C. Zn + CuSO₄ → ZnSO₄ + Cu
D. Na + Cl₂ → NaCl
33. When 5.0 g of H₂ reacts with 40.0 g of O₂ to form water, what is the limiting reagent?
2H2+O2→2H2O
A. H₂ B. O₂ C. H₂O D. Both reactants are in
excess
34. Which of the following factors does NOT affect the rate of a chemical reaction?
A. Temperature B. Concentration of reactants
C. Presence of a catalyst D. Color of the reactants
35. In an experiment to determine the boiling point of a liquid, which variable must be controlled
to ensure accurate results?
A. Volume of liquid B. Atmospheric pressure
C. Container material D. All of the above
36. Which best explains why gases can be compressed more easily than solids or liquids?
A. Gases have more mass per unit volume.
B. Gas particles are heavier than those in solids or liquids.
C. Gas particles are widely spaced with negligible intermolecular forces.
D. Gas particles occupy a fixed volume and are in constant motion.
37. Which condition would cause a real gas to deviate most from ideal behavior?
A. Low pressure and high temperature
B. High pressure and low temperature
C. Moderate pressure and moderate temperature
D. Low pressure and low temperature
38. A sealed container has equal masses of oxygen (O₂) and helium (He) gases at the same
temperature. According to the kinetic molecular theory, which gas has higher average kinetic
energy?
A. Oxygen, because it is diatomic
B. Helium, because it has a lower molar mass
C. Both have the same average kinetic energy
D. Cannot be determined without volume information
39. A syringe filled with a gas is sealed and submerged in ice water, causing the plunger to move
inward. Which gas law explains this observation?
A. Boyle’s Law B. Charles’s Law C. Avogadro’s Law D. Dalton’s Law
40. A car tire has a pressure of 2.5 atm at 25°C. After a long drive, the temperature inside the tire
reaches 50°C. What is the new pressure, assuming volume is constant?
A. 2.1 atm B. 2.8 atm C. 3.1 atm D. 3.5 atm
41. A 5.0 L gas sample at 300 K and 1.0 atm is compressed to 2.5 L and cooled to 150 K. What
is the final pressure?
A. 1.0 atm B. 2.0 atm C. 4.0 atm D. 6.0 atm
42. Which gas will effuse fastest under the same conditions: NH₃, O₂, Cl₂, or CO₂?
A. NH₃ B. O₂ C. CO₂ D. Cl₂
43. A compound isolated from a plant extract is found to be an isomer of C₄H₈O₂. It has a fruity
smell, is soluble in organic solvents but not in water, and does not react with Tollens' reagent. It
is used as a flavoring agent in the food industry.
Which of the following is most likely the correct name and class of this compound?
A. Butanoic acid, carboxylic acid
B. Methyl propanoate, ester
C. Butan-2-one, ketone
D. Butanal, aldehyde
44. A student is analyzing a hydrocarbon isolated from petroleum distillation. The compound:
Has the molecular formula C₆H₁2
Decolorizes bromine water rapidly in the dark
Can be converted into hexane via catalytic hydrogenation
Exhibits cis-trans isomerism
Is used industrially in the synthesis of plastics and synthetic rubber
Which of the following compounds is the most likely identity of the hydrocarbon?
A. Hexyne
B. Cyclohexane
C. 2-Hexene
D. 2-Methylpentane
45. Which of the following statements best explains why ethanol can be used both as a fuel
additive and a solvent in pharmaceuticals?
A. Ethanol is a hydrocarbon with a high energy content and is nonpolar, making it suitable for
dissolving oils.
B. Ethanol contains a hydroxyl group that allows it to undergo polymerization reactions, making
it ideal for plastics.
C. Ethanol is a small molecule with both polar and nonpolar characteristics, making it versatile
in combustion and solubility.
D. Ethanol reacts with acids to form esters, which makes it suitable for use in pesticides and
herbicides.
46. Which of the following best describes the historical development of organic chemistry?
A. It began with the study of metals and minerals.
B. It focused initially on compounds derived from living organisms.
C. It was developed solely by German scientists in the 19th century.
D. It only became relevant with the invention of plastics.
47. Which reaction is commonly used in the preparation of alkenes?
A. Combustion B. Esterification
C. Dehydration of alcohols D. Neutralization
48. Which of the following pairs are isomers?
A. Ethane and Ethene B. Propane and Propene
C. Butane and 2-Methylpropane D. Methane and Methanol
49. When a protic acid (like HCl or HBr) is added to an asymmetric alkene, which of the
following is true according to Markovnikov's Rule?
A. The hydrogen (H) will add to the carbon with fewer hydrogen atoms, and the halide (X) will
add to the carbon with more hydrogen atoms.
B. The hydrogen (H) will add to the carbon with more hydrogen atoms, and the halide (X) will
add to the carbon with fewer hydrogen atoms.
C. Both the hydrogen and halide will add equally to the carbons in the double bond.
D. The addition will be random and not follow any pattern
50. Which of the following statements about alcohols is true?
A. Alcohols are always non-polar compounds and do not interact with water.
B. Alcohols with fewer than 4 carbon atoms are typically soluble in water.
C. Primary alcohols have two alkyl groups attached to the carbon atom bearing the hydroxyl
group.
D. The general formula for alcohols is CnH2n.
51. Which of the following compounds is correctly classified as an oxide of a non-metal, and
is also amphoteric?
A. Sodium oxide (Na₂O) B. Carbon monoxide (CO)
C. Sulfur dioxide (SO₂) D. Magnesium oxide (MgO)
52. What is the concentration of OH⁻ ions in a solution that has a pH of 3?
A. 1 x 10⁻¹⁰ M B. 1 x 10⁻11 M C. 1 x 10⁻³ M D. 1 x 10⁻⁴ M
53. How does a chemical reaction produce an electric current in an electrochemical cell?
A. By converting heat energy into electrical energy
B. By the movement of ions in the electrolyte
C. By the transfer of electrons through an external circuit
D. By the decomposition of water into hydrogen and oxygen
54. What is the primary difference between metallic conduction and electrolytic
conduction?
A. Metallic conduction occurs when ions move, while electrolytic conduction occurs when
electrons move
B. Metallic conduction occurs through the movement of electrons, while electrolytic conduction
involves the movement of ions
C. Metallic conduction happens in non-metallic materials, while electrolytic conduction happens
in metals
D. There is no difference; both involve electron movement in a metal
55. In the electrolysis of molten sodium chloride (NaCl), what is the product formed at the
cathode?
A. Chlorine gas (Cl2) B. Sodium metal (Na)
C. Sodium chloride (NaCl) D. Oxygen gas (O2)
56. Which of the following is a characteristic of a voltaic (galvanic) cell?
A. It uses an external power source to drive the reaction
B. The anode is positively charged
C. It converts chemical energy into electrical energy
D. It involves electrolysis to break down compounds
57. In the electroplating of copper, which substance would be the anode?
A. Copper B. Silver C. Zinc D. Gold
58. Which of the following is a product of the electrolysis of water?
A. Hydrogen gas at the anode and oxygen gas at the cathode
B. Hydrogen gas at the cathode and oxygen gas at the anode
C. Hydrogen gas and oxygen gas at the anode
D. Oxygen gas at both electrodes
59. In Ethiopia, which of the following industries would most likely utilize local limestone
as a primary raw material?
A. Tanning B. Cement production C. Paper manufacturing D. Sugar refining
60. What distinguishes renewable natural resources from non-renewable ones in terms of
industrial use?
A. Renewable resources are only found in organic materials.
B. Renewable resources replenish naturally within a human timescale, unlike non-renewable
ones.
C. Renewable resources have higher chemical reactivity.
D. Non-renewable resources are never used in the energy sector.
61. During aluminium extraction, cryolite is used in the electrolytic process to:
A. Reduce aluminium oxide to aluminium metal
B. Increase the reactivity of aluminium
C. Decrease the melting point of aluminium oxide
D. Prevent aluminium from oxidizing
62. If a glass factory releases untreated fluoride-rich effluents into a nearby river, which
type of pollution is primarily involved and what is one potential consequence?
A. Air pollution – causes ozone depletion
B. Water pollution – harms aquatic life and causes bioaccumulation
C. Land pollution – reduces soil fertility
D. Air pollution – causes respiratory diseases in humans
63. The emission of light by an atom occurs when an electron transitions from a higher energy
level to a lower energy level. This process is explained by:
A. The photoelectric effect.
B. The Bohr model of the atom.
C. The Heisenberg uncertainty principle.
D. The Schrodinger wave equation.
64. Which of the following molecules has the largest bond angle?
A. NH₃ B. H₂O C. CH₄ D. CO₂
65. Which of the following correctly describes the shape and hybridization of the central atom in
SF₄?
A. Tetrahedral; sp³
B. See-saw; sp³d
C. Trigonal bipyramidal; sp³d
D.Square planar; dsp²
66. Which of the following species has a square pyramidal molecular geometry?
A. SF₆ B. IF₅ C. XeF₄ D. PCl₅
67. Which of the following species is least stable based on bond order?
A. N₂ B. O₂⁺ C. O₂ D. O₂²⁻
68. Ammonia is produced industrially by the Haber process:
N2(g)+3H2(g)⇌2NH3(g)ΔH=−92 kJ/mol
At a given temperature and pressure, a mixture of N₂, H₂, and NH₃ is allowed to reach
equilibrium in a sealed 10.0 L container. The equilibrium concentrations are as follows:
[N2]=0.25 mol/L[, [H2]=0.50 mol/L and [NH3]=1.50 mol/L
A chemist increases the temperature and then immediately adds a catalyst to the system. Which
of the following statements is most accurate?
A. The position of equilibrium shifts to the left, and the catalyst increases the final yield of
ammonia.
B. The value of KC increases and the catalyst speeds up both the forward and reverse reactions
equally.
C. The reaction shifts to favor the reactants, and the catalyst has no effect on the position of
equilibrium.
D. The concentration of H₂ decreases, and the equilibrium constant KC remains unchanged due
to the catalyst.
69. In the reaction:
2SO2(g)+O2(g)⇌2SO3(g)
At equilibrium, the partial pressures of SO2, O2, and SO3 are 0.5 atm, 0.5 atm, and 2 atm,
respectively. What is the value of Kp for this reaction?
A. 4 B. 16 C. 0.25 D. 1.0
70. If a chemical reaction at equilibrium has a very small value for Kc, what does this indicate
about the reaction?
A. The reaction favors the products.
B. The reaction favors the reactants.
C. The reaction reaches equilibrium very slowly.
D. The equilibrium is very sensitive to temperature changes.
71. Which polymer is made by addition polymerization?
A. Nylons B. Polyethylene C. Polyesters D. Bakelite
72. What defines a homopolymer?
A. It is made from one type of monomer.
B. It is made from two or more different types of monomers.
C. It undergoes condensation polymerization.
D. It is always a natural polymer
73. Which type of polymerization involves the formation of by-products such as water or
methanol during the polymerization process?
A. Addition polymerization B. Condensation polymerization
C. Cross-linking polymerization D. Free radical polymerization
74. What is the primary difference between thermoplastics and thermosetting plastics?
A. Thermoplastics cannot be molded once solidified.
B. Thermoplastics can be remolded multiple times upon heating, whereas thermosetting plastics
cannot.
C. Thermoplastics are made from addition polymerization, while thermosetting plastics are made
from condensation polymerization.
D. Thermoplastics are used for biological applications, while thermosetting plastics are used in
synthetic fibers
75. Which of the following monomers are used to produce Nylons?
A. Ethylene glycol and terephthalic acid
B. Styrene and butadiene
C. Hexamethylenediamine and adipic acid
D. Methyl methacrylate and styrene
76. The polymer polymethyl methacrylate (PMMA) is commonly known as:
A. Plexiglass B. Nylon C. Teflon D. Polyester
77. Which process is used for the large-scale production of sulfuric acid?
A. Ostwald Process B. Contact Process C. Haber - Bosch process D. Solvay Process
78. Which of the following is used in the saponification process to make soap?
A. NaOH and fat B. NaOH and alcohol
C. NaOH and sulfuric acid D. Fat and alcohol
79. The process in which sodium carbonate is manufactured is called:
A. Calcination B. Metallurgy C. Solvay Process D. Carbonation
80. Four students of grade 12A—Ronaldo, Mesi, Sala, and Nunez—were each given test tubes
with unknown solutions and allowed to measure their pH with a pH meter. They found the
following pH values: 3, 12, 7, and 9, respectively. Based on this information, identify the correct
statement:
A. Sala’s test tube has a higher hydronium ion concentration than Mesi’s one.
B. Mesi’s test tube contains definitely an acid.
C. Ronaldo’s test tube contains the highest concentration of hydroxide ions.
D. The hydrogen ion concentration in Nunez’s test tube is the highest.
